[Federal Register Volume 59, Number 140 (Friday, July 22, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-17798]


[[Page Unknown]]

[Federal Register: July 22, 1994]


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Part V





Department of Transportation





_______________________________________________________________________



Federal Aviation Administration



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14 CFR Parts 23 and 91




Airworthiness Standards; Systems and Equipment Proposals Based on 
European Joint Aviation Requirements Proposals; Proposed Rule
DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 23 and 91

[Docket No. 27806; Notice No. 94-21]
RIN: 2120-AE59

 
Airworthiness Standards; Systems and Equipment Proposals Based on 
European Joint Aviation Requirements Proposals

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes changes to the systems and equipment 
airworthiness standards for normal, utility, acrobatic, and commuter 
category airplanes. These proposals arise from the joint effort of the 
Federal Aviation Administration (FAA) and the European Joint Aviation 
Authorities (JAA) to harmonize the Federal Aviation Regulations (FAR) 
and the Joint Aviation Requirements (JAR) for airplanes that will be 
certificated in these categories. The proposed changes would provide 
nearly uniform systems and equipment airworthiness standards for 
airplanes certificated in the United States under 14 CFR part 23 (part 
23) and in the JAA countries under Joint Aviation Requirements 23 (JAR 
23), thereby simplifying airworthiness approval for import and export 
purposes.

DATES: Comments must be submitted on or before November 21, 1994.

ADDRESSES: Comments on this document should be mailed in triplicate to: 
Federal Aviation Administration, Office of the Chief Counsel, 
Attention: Rules Docket (AGC-200), Docket No. 27806, 800 Independence 
Avenue SW., Washington, DC 20591.
    Comments delivered must be marked Docket No. 27806. Comments may be 
inspected in Room 915G weekdays between 8:30 a.m. and 5 p.m., except on 
Federal holidays.
    In addition, the FAA is maintaining an information docket of 
comments in the Office of the Assistant Chief Counsel, ACE-7, Federal 
Aviation Administration, Central Region, 601 East 12th Street, Kansas 
City, Missouri 64106. Comments in the duplicate information docket may 
be inspected in the Office of the Assistant Chief Counsel weekdays, 
except Federal holidays, between the hours of 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: Earsa Tankesley, ACE-112, Small 
Airplane Directorate, Aircraft Certification Service, Federal Aviation 
Administration, 601 East 12th Street, Kansas City, Missouri 64106; 
telephone (816) 426-5688.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Comments relating to the environmental, energy, or 
economic impact that might result from adopting the proposals in this 
notice are also invited. Substantive comments should be accompanied by 
cost estimates. Comments should identify the regulatory docket or 
notice number and should be submitted in triplicate to the Rules Docket 
address specified above. All comments received on or before the 
specified closing date for comments will be considered by the 
Administrator before taking action on this proposed rulemaking. The 
proposals contained in this notice may be changed in light of comments 
received. All comments received will be available, both before and 
after the closing date for comments, in the Rules Docket for 
examination by interested persons. A report summarizing each FAA-public 
contact concerned with the substance of this proposal will be filed in 
the docket. Commenters wishing the FAA to acknowledge receipt of their 
comments submitted in response to this notice must include a 
preaddressed, stamped postcard on which the following statement is 
made: ``Comments to Docket No. 27806.'' The postcard will be date 
stamped and returned to the commenter.

Availability of NPRM

    Any person may obtain a copy of this NPRM by submitting a request 
to the Federal Aviation Administration, Office of Public Affairs, 
Attention: Public Inquiry Center, APA-200, 800 Independence Avenue, 
SW., Washington, DC 20591, or by calling (202) 267-3484. Communications 
must identify the notice number of this NPRM.
    Persons interested in being placed on the mailing list for future 
NPRM's should request, from the above office, a copy of Advisory 
Circular No. 11-2A, Notice of Proposed Rulemaking Distribution System, 
which describes the application procedure.

Background

    At the June 1990 meeting of the JAA Council (consisting of JAA 
members from European countries) and the FAA, the FAA Administrator 
committed the FAA to support the harmonization of the FAR with the JAR 
being developed for use by the European authorities who are members of 
the JAA. In response to this commitment, the FAA Small Airplane 
Directorate established an FAA Harmonization Task Force to work with 
the JAR 23 Study Group to harmonize part 23 and the proposed JAR 23. 
The General Aviation Manufacturers Association (GAMA) also established 
a JAR 23/part 23 Committee to provide technical assistance in this 
effort.
    Following a review of the first draft of proposed JAR 23, members 
of the FAA Harmonization Task Force and the GAMA Committee met in 
Brussels, Belgium for the October 1990 meeting of the JAR 23 Study 
Group. Representatives from the Association Europeene des 
Constructeures de Material Aerospatial (AECMA), an organization of 
European airframe manufacturers, also attended. The main agenda item 
for this meeting was the establishment of procedures to accomplish 
harmonization of the airworthiness standards for normal, utility, and 
acrobatic category airplanes. The JAA had decided that its initial 
rulemaking effort should be limited to these three categories and that 
commuter category airworthiness standards should be addressed 
separately.
    After that meeting, technical representatives from each of the four 
organizations (GAMA, AECMA, FAA and JAA) met to resolve differences 
between the proposed JAR and part 23. This portion of the harmonization 
effort involved a number of separate meetings of specialists in the 
flight, airframe, powerplant, and systems disciplines. These meetings 
showed that harmonization would require revisions to both part 23 and 
the proposed JAR 23.
    Near the end of the effort to harmonize the normal, utility, and 
acrobatic category airplane airworthiness standards, the JAA requested 
and received recommendations from its member countries on proposed 
airworthiness standards for commuter category airplanes. The JAA and 
the FAA held specialist and study group meetings to discuss these 
recommendations, which resulted in proposals to revise portions of the 
part 23 commuter category airworthiness standards.
    Unlike the European rules, where commuter category airworthiness 
standards are separate, for U.S. rulemaking, it is advantageous to 
adopt normal, utility, acrobatic, and commuter category airworthiness 
standards simultaneously, since commuter category airworthiness 
standards are already contained in part 23. Accordingly, this NPRM 
proposes to revise the systems and equipment airworthiness standards 
for all part 23 airplanes.
    During the part 23 harmonization effort, the FAA established an 
Aviation Rulemaking Advisory Committee (ARAC) (56 FR 2190, January 22, 
1991), which held its first meeting on May 23, 1991. The ARAC on 
General Aviation and Business Airplane (GABA) Issues was established at 
that meeting to provide advice and recommendations to the Director, 
Aircraft Certification Service, FAA, regarding the airworthiness 
standards in part 23 as well as related provisions of parts 91 and 135 
of the regulations.
    The FAA announced, on June 2-5, 1992, at the JAA/FAA Harmonization 
Conference in Toronto, Ontario, Canada, that it would consolidate 
within the ARAC structure an ongoing objective to ``harmonize'' the JAR 
and the FAR. Coinciding with that announcement, the FAA assigned the 
ARAC on GABA Issues those rulemaking projects related to JAR/part 23 
harmonization that were in final coordination between the JAA and the 
FAA. The harmonization process included the intention to present the 
results of JAA/FAA coordination to the public as NPRM's. Subsequently, 
the ARAC on GABA Issues established an ARAC-JAR 23 Study Group.
    The JAR 23 Study Group made recommendations to the ARAC on GABA 
Issues concerning the FAA disposition of the rulemaking issues 
coordinated between the JAA and the FAA. The draft NPRMs previously 
prepared by the FAA harmonization team were made available to the 
harmonization working group to assist them in their effort.
    A notice of the formation of the JAR 23 Harmonization Working Group 
was published on November 30, 1992 (57 FR 56626). The group held its 
first meeting on February 2, 1993. These efforts resulted in the 
proposals for systems and equipment airworthiness standards contained 
in this notice. The ARAC on GABA Issues agreed with these proposals.
    The FAA received unsolicited comments from the JAA dated January 
20, 1994, concerning issues that were left unresolved with the JAR 23 
Study Group. The JAR/FAR 23 Harmonization Working Group did not address 
some of the unresolved issues because the JAA had not yet reached 
positions on those issues. Unresolved issues will be dealt with at 
future FAR/JAR Harmonization meetings. With respect to other issues 
unresolved by the JAR 23 Study Group, the JAR/FAR 23 Harmonization 
Working Group recommendations did not reflect harmonization, but 
reflected the technical discussion of the merits of each issue that had 
been thoroughly debated at the JAR/FAR 23 Harmonization meetings. (The 
Working Group Chairperson had been present at the Harmonization 
meetings.) The JAA comments have been placed in the docket for this 
proposal, and will be considered along with those received during the 
comment period.
    Following completion of these harmonization efforts, the FAA 
determined that the proposed revisions to part 23 were too numerous for 
a single NPRM. The FAA decided to simplify the issues by issuing four 
NPRM's. These NPRM's address the airworthiness standards in the 
specific areas of systems and equipment, powerplant, flight, and 
airframe. These NPRM's propose changes in all seven subparts of part 
23. Since there is some overlap, interested persons are advised to 
review all four NPRM's to identify all proposed changes to a particular 
section.

Discussion of Proposals

Section 23.677  Trim Systems

    Proposed revised Sec. 23.677(a) would clarify the need to mark the 
lateral and directional trim indicators with the neutral trim position. 
Since trim indicators on most airplanes are currently marked with the 
neutral position of the trimming device, this proposal would 
standardize the cockpit markings for all airplanes.
    Revised paragraph (a) would also add a requirement for the pitch 
trim indicator to be marked with the proper pitch trim range for the 
takeoff of the airplane. Some takeoff accidents, including some 
involving fatalities, have occurred because the pitch trim was not set 
to the proper range needed for the airplane takeoff. Because of this 
accident experience, most of the current airplane manufacturers mark 
the pitch trim indicator with the pitch trim range for takeoff. 
Therefore, the proposed marking requirement would not have a 
significant impact on future airplane designs and would ensure that the 
markings needed for a safe takeoff are provided for the pilots' use.

Section 23.691  Artificial Stall Barrier System

    This proposed new section would provide standards for stall barrier 
systems if a stall barrier is necessary to show compliance with 
Sec. 23.201(c).
    The requirements of Sec. 23.201(c) provide criteria for the in-
flight demonstration of wings level stall. The requirements also 
specify the means of identifying when a stall has occurred. Amendment 
No. 23-45 (58 FR 42136, August 6, 1993) revised Sec. 23.201(c) by 
adding the activation of an artificial stall barrier as an acceptable 
means of identifying when a stall has occurred.
    As the technology of airplane designs improved and engines with 
increased power became available, airplanes were developed that did not 
meet the older wings level stall requirement of Sec. 23.201. 
Consequently, these airplanes were equipped with an artificial stall 
barrier that moved the airplane elevator controls and caused a nose 
down pitching motion similar to the pitching motion of airplanes that 
meet the wings level stall requirement of Sec. 23.201. The manufacturer 
selected the airspeed where this pitching motion occurred and flight 
testing established compliance with the other flight regulations at 
airspeeds above the speed selected for the push. These stall barrier 
systems are commonly called ``stick pushers.'' Such systems have been 
accepted for compliance with Sec. 23.201 under the equivalent safety 
provisions of Sec. 21.21(b)(1), since they provide a pitch motion that 
is equivalent to that experienced during stalls of airplanes that meet 
the stall requirements of Sec. 23.201. Appropriate compliance with 
other applicable requirements of part 23 has been established by other 
design characteristics of the stall barrier system.
    The provisions of the proposed new section are based on system 
design characteristics necessary to ensure the safe operation of 
previously approved stall barrier systems. The proposed section also 
requires such systems to include provisions to prevent unwanted 
activation of the stall barrier systems. This is necessary to ensure 
that such systems do not cause downward pitching motions at higher 
airspeeds when such pitching could be unsafe.
    The proposed sections would basically codify those provisions that 
have been found necessary for approving stick pusher systems under the 
equivalent safety requirements of Sec. 21.21(b)(1). Therefore, in 
effect, no new requirements would be added by this proposed amendment.
    The proposed new section would be applicable only to airplanes with 
flight characteristics that need an artificial stall barrier system to 
ensure safe operation of that airplane. Including provision for the 
installation of an optional stick pusher system would relieve the 
manufacturer of the financial burden that would be needed to redesign 
the airplane so that it would meet the wings level stall requirements.

Section 23.697  Wing Flap Controls

    Proposed new Sec. 23.697(c) would provide safety standards for the 
wing flap control lever designs installed in airplanes that use wing 
flap settings other than fully retracted when showing compliance with 
Sec. 23.145. This revision is needed to ensure that the flap settings, 
which establish the safe operation of the airplane, can be positively 
selected.

Section 23.701  Flap Interconnection

    Section 23.701 (a)(1) and (a)(2) would be revised to clarify the 
requirements for flap systems installed on part 23 airplanes. Following 
the revision of Sec. 23.701, as adopted by Amendment No. 23-42 (56 FR 
353, January 3, 1991), the FAA discovered that the new requirements 
could be interpreted in a way that was not intended and that this 
interpretation could result in approval of airplanes with unsafe flight 
characteristics in the event of flap failure. To clarify the intent of 
the requirements, the FAA issued on March 14, 1991, a policy letter to 
all aircraft certification offices that provided guidance for the 
correct application of the requirements.
    Since then, the FAA has reexamined the requirements and determined 
that Sec. 23.701 (a)(1) and (a)(2) need to be revised to ensure that a 
failure of the flap system would not create an asymmetric flap 
configuration that could result in an unsafe flight condition. 
Therefore, Sec. 23.701 (a)(1) and (a)(2) would be revised to clarify 
that one of the following would apply:
    (1) The moveable flap surfaces must be synchronized by a mechanical 
interconnection or by an approved equivalent means, that is independent 
of the flap drive system.
    (2) The wing flap system must be designed so that any failures of 
the flap system that would result in an unsafe flight characteristic of 
the airplane, such as flap asymmetry, is extremely improbable.
    These revisions would ensure that a failure of the flap drive 
systems will not result in a flap asymmetry configuration.

Section 23.703  Takeoff Warning System

    This proposed new section would require a takeoff warning system on 
some commuter category airplanes. The requirement would be applicable 
if the flight evaluation showed that an unsafe takeoff condition would 
result if lift devices or longitudinal trim devices are set to any 
position outside the approved takeoff range. If the evaluation shows 
that no unsafe condition would result at any setting of these devices, 
a takeoff warning system would not be required. For those airplanes on 
which a warning system must be installed, the proposal would provide 
requirements for the installation of the system.

Section 23.723  Shock Absorption Tests

    Paragraph (b) of this section would be revised by changing the word 
``reserved'' in the phrase ``reserved energy absorption capacity'' to 
``reserve.''

Section 23.729  Landing Gear Extension and Retraction System

    This proposal would revise Sec. 23.729(e) to clarify that a landing 
gear indicator is required for each gear. The last sentence of current 
Sec. 23.729(e) would also be removed. This sentence, which states that 
the switches may be located where they are operated by the actual 
landing gear locking latch or device, is advisory material and should 
not be included in the requirements. If future guidance is needed to 
identify acceptable switch locations, Advisory Circular 23.701-1 will 
be revised to include that information.
    This proposal would also add a new Sec. 23.729(g) requiring that if 
the landing gear bay is used as the location for equipment other than 
landing gear, the equipment must be designed and installed to minimize 
damage. On larger airplanes, such as the commuter category, a primary 
cause of damage to such equipment would be tire burst. In addition, 
service history has shown that rocks, water, and slush enter the 
landing gear bay and cause damage. The equipment on any size airplane 
should be protected from damage by such external sources.

Section 23.735  Brakes

    Section 23.735(a) would be revised to state plainly that wheel 
brakes must be provided. A proposed new Sec. 23.735(c) would require 
the brake system to be designed so that the brake manufacturer's 
specified brake pressures are not exceeded during the landing distance 
determination required by Sec. 23.75.
    Proposed new Sec. 23.735(e), applicable to commuter category 
airplanes, would require establishing the minimum rejected takeoff 
brake kinetic energy capacity rating of each main wheel brake assembly. 
Section 23.45 provides that the determination of the accelerate-stop 
distance for commuter category airplanes be made in accordance with the 
applicant's procedures for operation in service. The proposed 
requirement is needed to ensure that the brakes will perform safely 
under accelerate-stop conditions.

Section 23.745  Nose/Tail Wheel Steering

    Proposed new Sec. 23.745 would provide requirements that apply if 
nose/tail-wheel steering is installed. Advanced airplane design 
technology, along with the need to safely control the airplane when it 
is being operated on increasingly congested airports, has resulted in 
several small airplanes being equipped with systems for ground steering 
only.
    The proposed new section would not require the installation of a 
system for ground steering, but it would add requirements to define how 
such a system should function if one is installed. It would also 
require the steering system to be designed so that it will not 
interfere with any installed landing gear retraction and extension 
system.

Section 23.775  Windshields and Windows

    Section 23.775(a) would be revised to state that internal glass 
panels of windshields and windows must be constructed of a 
nonsplintering material, such as nonsplintering glass. Currently 
Sec. 23.775(a) requires nonsplintering safety glass only. A 
nonsplintering material must be used to protect pilots from injury. 
While nonsplintering glass is an acceptable standard, other 
nonsplintering materials would be allowed under the proposal.
    Section 23.775(c) would be revised to clarify that it applies to 
pressurized airplanes if certification for operation up to and 
including 25,000 feet is requested. This would not be a substantive 
change. It has always applied to such airplanes but is not as directly 
stated in the current rule as it would be in the proposed rule. Current 
Sec. 23.775(e), which is being redesignated as Sec. 23.775(d) by this 
notice without change, provides requirements for airplanes that are 
certified for operations above 25,000 feet. This revision of paragraph 
(c) and redesignation of paragraph (e) will clarify the requirements 
that are applicable to airplanes approved for operations at different 
altitudes. Redesignated paragraph (e) is revised to remove the 
masculine gender by rephrasing ``when he is seated'' to read ``when the 
pilot is seated.''
    Section 23.775(h), introductory text, and paragraph (h)(1) would be 
added to require windshield panes of commuter category airplanes that 
are directly in front of the pilots to withstand the impact of a two 
pound bird. This requirement is based on a Joint Aviation Authority 
recommendation to add windshield bird strike protection for commuter 
category airplanes. Following receipt of the recommendations, the FAA 
obtained and reviewed the International Civil Aviation Organization 
(ICAO) data on bird strikes that occurred on airplanes of 19,000 pounds 
or less from 1981 through 1989. These data show that approximately 550 
strikes occurred and that one out of seven strikes hit the windshield. 
The bird strike reports, which include information on the type of bird, 
the airplane altitude and/or airspeed, show the following:
    1. More than one-half of the strikes (51.8 percent) occurred 
between the ground and 100 feet above the ground.
    2. Another one-fourth of the strikes (26.7 percent) occurred 
between 101 and 1000 feet.
    3. The airplane airspeed at the time of most of the strikes (85 
percent) was 150 knots or less.
    4. Where bird types were reported, 27.6 percent involved small 
birds and 58.6 involved medium size birds.
    5. Incidents where the airplane was damaged showed that 16.9 
percent resulted from small bird strikes and 64 percent resulted from 
strikes involving medium size birds.
    Evaluation of these data indicate that most bird strikes occur at 
takeoff and landing altitudes and airspeeds, and that medium or small 
birds, many weighing two pounds or less, are most often struck. 
Although only a few fatalities and injuries have resulted from these 
reported bird strikes, the data indicates a high probability of bird 
strikes during landings and takeoffs and the potential hazards of such 
strikes.
    This proposed new paragraph would require that the windshield panes 
directly in front of the pilots of commuter category airplanes, and the 
supportive structure for these panes, must withstand the impact of a 
two-pound bird at an airplane's maximum approach flap speed.
    Proposed Sec. 23.775(h)(2) would require the panels of the 
windshield to be arranged so that, if one is damaged, other panels will 
remain that will provide visibility for continuous safe flight and 
landing of the airplane.
    By requiring full protection against the strike of a two-pound bird 
at approach speeds, some protection will also be provided if the 
airplane strikes a larger bird or strikes a bird at a higher speed.

Section 23.783  Doors

    Current Sec. 23.783(b) requires that passenger doors not be located 
with respect to any propeller disk so as to endanger persons using the 
door. Proposed paragraph (b) would add that passenger doors must be 
located in relation to any other potential hazard that could endanger 
persons using the door. The propeller disk remains the prominent hazard 
but other items, such as hot deicer surfaces or sharp objects on the 
airplane structure, are also hazards.
    Proposed new paragraph (g) would require lavatory doors, if 
installed, that would not trap occupants inside a closed and locked 
lavatory compartment.

Section 23.785  Seats, Berths, Litters, Safety Belts, and Shoulder 
Harnesses

    Seat requirements of part 23 would be clarified by moving the seat 
provisions in current Sec. 23.1307(a), which require a seat or berth 
for each occupant, to the introductory text of Sec. 23.785. The 
requirement of Sec. 23.1413, for a metal to metal latching device for 
seat belts and shoulder harnesses would also be referenced in 
Sec. 23.785(b). These proposed changes would combine related seat 
requirements in one section.

Section 23.787  Baggage and Cargo Compartments

    Section 23.787 would be revised by extending the present 
requirements for cargo compartments to baggage compartments. As 
proposed, future baggage compartments on all airplane categories would 
be required to: Be placarded for their maximum weight capacity; have a 
means to prevent the baggage from shifting; and have a means to protect 
controls, wiring, lines, and equipment or accessories that are located 
in the compartment and whose damage or failure would affect safe 
operation of the airplane. These standards have been applicable to 
cargo compartment designs for some time and should be applied to 
baggage compartments since the same safety factors are involved. 
Because manufacturers recognize the need for these standards, many of 
these provisions have been included in the current design of baggage 
compartments and, therefore, the proposed requirements are not expected 
to create a significant burden. With this revision the commuter 
category requirements of Sec. 23.787(g) would be redundant and that 
requirement is being removed.
    Proposed revisions to this section would also move the substance of 
paragraphs (d) and (f) to a proposed new Sec. 23.855, which will 
address cargo and baggage compartment fire protection.
    Proposed new paragraph (c) of this section would require flight 
crew emergency exits on all cargo configured airplanes to meet the 
requirements of Sec. 23.807. This requirement would provide increased 
assurance that flight crews of all cargo airplanes will have ready 
access to an emergency exit.

Section 23.791  Passenger Information Signs

    This proposed new section would require at least one illuminated 
sign notifying all passengers when seat belts should be fastened. This 
proposed requirement applies to airplanes where flightcrew members 
cannot observe occupant seats or where the flightcrew member 
compartment is separated from the passenger compartment. When 
illuminated, the signs must be legible to all persons seated in the 
passenger compartment. Each sign must be installed so that a flightcrew 
member can turn it on and off from his or her station.

Section 23.807  Emergency Exits

    Proposed new Sec. 23.807(a)(4) would provide the same protection 
from any propeller disk and other potential hazard for a person who 
uses emergency exits as that provided by proposed Sec. 23.783(b) for a 
person who uses a passenger door. (See discussion for proposed 
Sec. 23.783 in this notice.)
    The proposed revision of Sec. 23.807(b) would provide that the 
inside handles of emergency exits that open outward must be protected 
against inadvertent operation. Currently this protection is required by 
applying the general safety provisions of this subchapter. The addition 
of the specific requirement in Sec. 23.807(b) would clarify the need 
for this protection by providing a requirement that addresses outward 
opening emergency exits.
    The proposed revision to Sec. 23.807(b)(5) and new 
Sec. 23.807(b)(6) would apply to acrobatic and utility category 
airplanes that are approved for maneuvers, such a spinning. The 
proposed rule would require that emergency exits for these category 
airplanes allow the occupants to abandon the airplane at certain speeds 
related to such maneuvers. These emergency exits need to function under 
different environmental conditions than the emergency exits on normal 
category airplanes. The revision of the text in paragraph (b)(5) would 
provide the same terminology that is used in added new paragraph 
(b)(6).

Section 23.841  Pressurized Cabins

    The proposed revision to Sec. 23.841(a) would extend the cabin 
pressure requirements of current paragraph (a), which now apply to 
airplanes certificated for operation above 31,000 feet, to airplanes 
certificated for over 25,000 feet. Current 14 CFR part 25, JAR 25, and 
proposed JAR 23 include the same requirement as this proposal. This 
proposed requirement is intended to protect the airplane occupants from 
harm if a malfunction occurs at altitudes where symptoms of hypoxia 
occur, usually above 25,000 feet. Due to the increasing use of turbine 
powered engines, more part 23 airplanes will be approved for operations 
above 25,000 feet, thus exposing an increasing number or occupants, who 
may have some breathing difficulties, to these altitudes. The occupants 
should have the same protection provided by the airworthiness standards 
of part 25 and JAR 25.

Section 23.853  Passengers and Crew Compartment Interiors

    This proposal would revise the section heading from ``Compartment 
Interiors'' to ``Passenger and crew compartment interiors'' for 
consistency with the introductory text of the section and to clarify 
the content of the section.

Section 23.855  Cargo and Baggage Compartment Fire Protection

    This proposed new section would require the following:
    Proposed paragraph (a) would require all sources of heat within 
each cargo and baggage compartment that are capable of igniting the 
compartment contents to be shielded and insulated to prevent such 
ignition.
    Proposed paragraph (b) would require cargo and baggage compartments 
to be constructed of materials that meet the appropriate provisions of 
Sec. 23.853(d)(3). Currently these requirements apply to commuter 
category airplanes and to the materials used in the compartments of 
these airplanes. The proposed new requirement would expand this 
applicability to the cargo and baggage compartments of all part 23 
airplanes. In effect, the proposed new requirement would require 
materials that are self-extinguishing rather than flame resistant as 
currently required under Sec. 23.787(d).
    Proposed new paragraph (c) would add new fire protection 
requirements for cargo and baggage compartments for commuter category 
airplanes. The proposed rule would require on of the following 
alternatives: (1) Either the compartment must be located where pilots 
seated at their duty station would easily discover the fire or the 
compartment must be equipped with a smoke or fire detector system to 
warn the pilot's station. The compartment must also provide access to 
the compartment with a fire extinguisher. (2) The compartment may be 
inaccessible, but must be equipped with a fire detector system that 
warns the pilot station, and the compartment must have ceiling and 
sidewall floor panels constructed of materials that have been subjected 
to and meet the vertical self-extinguishing tests of appendix F of this 
part. (3) The compartment must be constructed and sealed to contain any 
fire.
    The proposed new section is necessary for several reasons. The 
proposals for additional requirements for commuter category airplane 
cargo and baggage compartments were developed after an examination of 
reported incidents of inflight fires and their causes. Although most of 
these incidents of inflight fires occurred on transport category 
airplanes, the reported sources of the fires showed that the fires 
originate from sources, such as matches in the pockets of clothing, 
that are as likely to be found on part 23 airplanes as on transport 
category airplanes. The same potential for inflight fires exists on 
commuter category airplanes and adequate protection should be provided.
    The potential for inflight fires also showed a need to examine the 
flame resistant requirements of current Sec. 23.787(d) and to consider 
requirements that would improve the fire protection on other categories 
of airplanes. As a part of this consideration, fire protection was 
discussed with certain airframe manufacturing representatives. 
Information provided in these discussions showed that materials that 
meet self-extinguishing flame requirements are available at about the 
same cost as materials that meet flame resistance requirements. Based 
on a review of the fire incidents and the information on availability 
of improved materials, the proposal for Sec. 23.855(b), which would 
replace current Sec. 23.787(d), would require self-extinguishing 
materials to be used in the cargo and baggage compartments of all part 
23 airplanes.

Section 23.867  Electrical Bonding and Protection Against Lightning and 
Static Electricity

    This proposed revision would change the heading that precedes the 
section from ``Lightning Evaluation'' to ``Electrical Bonding and 
Lightning Protection.'' It would also revise the section heading from 
``Lightning protection of structures'' to ``Electrical bonding and 
protection against lightning and static electricity.'' The proposed 
revisions more accurately clarify the content of the section.

Section 23.1303  Flight and Navigation Instruments

    The lead in for Sec. 23.1303(a) would be revised to clarify that 
the instruments required by this section are the minimum ones required. 
Also, Sec. 23.1303(d) would add a requirement for those airplanes whose 
performance must be based on weight, altitude, and temperature to be 
equipped with a free air temperature indicator. A new sentence added to 
Sec. 23.1303(e)(2) would state that nuisance overspeed warnings should 
not occur at lower speeds where pilots might ignore the warning. A new 
paragraph (f) would propose requirements for attitude instruments that 
include a means for flightcrew members to adjust the reference symbol. 
Finally, it would add a new paragraph (g) to define certain specific 
instruments required for a commuter category airplane.
    The proposal for Sec. 23.1303(e)(2) was developed following a Joint 
Aviation Authority recommendation that the warning should not occur 
below the maximum operating limit speed (VMO/MMO)/ To 
determine the effect that this recommended VMO/MMO limit 
would have on the design of overspeed warning devices, the FAA 
contacted several equipment manufacturers. These manufacturers 
responded that it would be possible to establish a lower limit at 
VMO/MMO, but that the design changes needed to ensure that 
the warning occurred between the presently required upper limit and the 
recommended lower limit would be very expensive.
    The FAA notes that no known safety problem justifies that cost of 
these design changes. However, the FAA is also aware that if warnings 
of any type occur when the pilots know that no particular problem 
exists, such warnings may become a nuisance. If warnings become a 
nuisance, a pilot may disregard a warning when the airplane is 
approaching a flight speed where an unsafe flight condition may occur. 
Regulatory action is therefore needed to ensure that the warning will 
occur within appropriate speed limits. Proposed Sec. 23.1303(e)(2) 
would require manufacturers to establish a lower speed limit so that 
nuisance overspeed warnings will not occur. The manufacturer would be 
required to show that this limit is appropriate for the airplane design 
but would not be required to set this lower limit at one specific 
speed, such as VMO/MMO, which would be costly to achieve.
    A new Sec. 23.1303(f) is proposed because attitude instruments are 
available that provide a means accessible to the flightcrew members, 
for adjusting the reference symbol through ranges that could result in 
unsafe pitch angles in small airplanes. These instruments were 
developed for airplanes that use high pitch angles for approved climb 
or descent gradients. By permitting these airplanes to use instruments 
that can be adjusted for these higher pitch angles, pilots are able to 
maintain the design gradients using an instrument that provides a 
normal indication at that pitch.
    If such attitude instruments are installed in small airplanes, 
pilots could adjust the reference symbol to ranges that could result in 
unsafe pitch angles. The recommendation showed that some instruments 
can be adjusted to result in pitch angles that are nearly the same as 
the pitch angle that many small airplanes achieve before stalling. To 
preclude potential cases of unwanted pitch adjustments of attitude 
instruments installed in small airplanes, Sec. 23.1303(f) proposes to 
limit the adjustment range to that limit that is needed for parallax 
correction.
    Proposed new Sec. 23.1303(g) would identify specific instruments, 
and limits of those instruments, required for commuter category 
airplanes. When the JAA initiated their consideration of commuter 
category airplanes, one of the proposals they received recommended 
adding the instrument requirements of Sec. 25.1303 to part 23 for 
commuter category airplanes. In considering this recommendation, a 
review of the requirements showed that many instruments required under 
Sec. 25.1303 are presently required by the operating rules. In 
addition, Sec. 23.1583(h) requires a list of the equipment that must be 
installed for the kinds of operation for which the airplane is 
approved. Based on the review, it was determined that many of the 
requirements in Sec. 25.1303 would be redundant, and the recommendation 
was not accepted.
    In considering a portion of the recommendation to require a third 
attitude instrument, the FAA noted that Sec. 91.531(a)(3) requires a 
commuter category airplane of ten or more passengers to be operated 
with a second-in-command and that Sec. 23.1321 requires flight and 
navigation instruments for each required pilot. Accordingly, two 
attitude instruments are required for a ten passenger, IFR approved 
commuter category airplane. Service experience has shown that failures 
of an attitude instrument system can occur where there will be a time 
period in which the indicator appears to be working but is providing 
incorrect information. During such a failure of one instrument in an 
airplane equipped with only two instruments, the pilots may have 
difficulty determining which instrument to follow, and hazardous flight 
attitudes may result. A third attitude instrument would allow the crew 
to retain reliable attitude information at all times, and thus the 
proposed rule would require a third attitude instrument for commuter 
airplanes operated by two pilots.

Section 23.1307  Miscellaneous Equipment

    This proposal would remove the requirement of Sec. 23.1307(a) which 
is being added to Sec. 23.785. The discussion of Sec. 23.785 covers 
this change.
    Also, the provisions of Sec. 23.1307(b)(1), (b)(2), and (b)(3), are 
being removed from Sec. 23.1307. These requirements have been 
previously added to Secs. 23.1361, 23.1351, and 23.1357, respectively; 
therefore, they are redundant and may be removed. The designator for 
paragraph (c) has also been removed from the remaining text of this 
section.

Section 23.1309  Equipment, Systems, and Installations

    Proposed new Sec. 23.1309(a)(4) would correct an inadvertent 
omission that occurred when the FAA issued Amendment No. 23-41 (55 FR 
43306, October 26, 1990). The omitted requirement was adopted by 
Amendment No. 23-34 as a portion of Sec. 23.1309(d) and read: ``In 
addition, for commuter category airplanes, system and installations 
must be designed to safeguard against hazards to the airplane in the 
event of their malfunction or failure.'' (52 FR 1833, January 15, 
1987.) To correct this oversight, and to continue the single fault 
provision of this paragraph, Sec. 23.1309(a)(4) is being proposed.

Section 23.1311  Electronic Display Instrument Systems

    This proposal would revise Sec. 23.1311 to remove redundant 
requirements and to clarify which secondary instruments are required 
and the visibility requirements for these instruments. When 
Sec. 23.1311 was adopted by Amendment No. 23-41 (55 FR 43306, October 
26, 1990), several nonsubstantive changes were made to the proposals in 
Notice No. 89-6 (54 FR 9345, March 6, 1989) to remove the redundancy 
included in the notice. In the process certain provisions, such as the 
one that permitted the installation of mechanical secondary 
instruments, were inadvertently omitted from the final rule. Since the 
final rule, discussions with airplane manufacturer representatives have 
shown that the requirements defining the instrument panel location 
where secondary instruments may be installed are also not clear. 
Accordingly, the FAA is proposing to revise this section to correct and 
clarify these portions.
    Current Sec. 23.1311(a), which requires electronic display 
indicator installations that are independent to each pilot station, 
would be deleted because it is redundant with Sec. 23.1321(a). Section 
23.1321(a) requires that each flight, navigation, and powerplant 
instrument for use by any required pilot shall be located so that any 
pilot seated at the controls can monitor the instruments with minimum 
head and eye movement. As stated in the preamble of Notice No. 89-6 (54 
FR 9345, March 6, 1989) regarding the proposed revision to 
Sec. 23.1321, ``This revision also clarifies the rule relative to 
instrumentation that must be provided for each pilot required for type 
certification or by the applicable operating rules. If a pilot is 
required by any applicable requirement, then that pilot must be 
provided all instrumentation required for any operations for which the 
airplane is approved.'' Accordingly, the requirements of current 
Sec. 23.1311(a) would be removed.
    In place of current paragraph (a), proposed Sec. 23.1311(a) would 
be a revision of current paragraph (c) that would clarify what 
instruments are required and the visibility of those instruments. 
Proposed new Sec. 23.1311(a)(1) would require electronic display 
instrument installations to meet the arrangement and visibility 
requirements of Sec. 23.1321(a).
    Proposed Sec. 23.1311(a) (2), (3), and (4) would be redesignated 
with no changes from current Sec. 23.1311(c) (1), (2), and (3).
    Proposed Sec. 23.1311(a)(5) would continue the requirement of 
Sec. 23.1303(c) for a magnetic direction indicator and, in addition, 
would require either an independent secondary mechanical altimeter, 
airspeed indicator, and attitude indicator or individual electronic 
display indicators for the altimeter, airspeed, and attitude that are 
independent from the airplane's primary electrical power. These 
secondary instruments may be installed in panel positions other than 
the primary location as long as the selected location allows the pilot 
to properly monitor the instruments and control the airplane.
    The substance of proposed paragraph (a)(5) is both a substantive 
change and a combination of the current Sec. 23.1311(b), which states 
that certain electronic display indicators must be independent of the 
airplane's electrical power system, and current Sec. 23.1311(c)(4) 
which requires independent secondary attitude and rate-of-turn 
instruments and specifies the location of those instruments. Proposed 
Sec. 23.1311(a)(5) would delete the requirement for a rate-of-turn 
instrument (in current Sec. 23.1311(c)(4)) and specify that the 
required secondary instruments are those that provide altitude, 
airspeed, magnetic direction, and attitude. The information that would 
be provided by a secondary rate-of-turn instrument would not 
appreciably add to the safe operations of the airplane if the pilot has 
the information provided by the secondary attitude instrument.
    Current Sec. 23.1311(b) requires that electronic display indicators 
required by Sec. 23.1303 (a), (b), and (c) be independent of the 
airplane's electrical power system. The original intent of the 
requirement for secondary instruments, as stated in Notice No. 89-6, 
was to require the installation of either mechanical instruments or 
independent electronic display indicators powered by a source 
independent of the airplane's electrical system. However, the current 
rule does not clearly state this and does not address the installation 
of mechanical instruments. Proposed Sec. 23.1311(a)(5), would allow 
either secondary electronic display indicators or mechanical 
instruments to provide a crew with information essential for continued 
flight and landing in the event of failure in the airplane's electrical 
power system.
    Current Sec. 23.1311(c) (5) and (6) would be redesignated as 
Sec. 23.1311(a) (6) and (7) without change.
    Proposed new Sec. 23.1311 (b) and (c) would continue the 
requirements of current Sec. 23.1311 (d) and (e) without change.

Section 23.1321  Arrangement and Visibility

    The proposed revision to Sec. 23.1321(d) would remove the wording 
that limits the instrument location requirement to airplanes 
certificated for flight under instrument flight rules or airplanes 
weighing more than 6,000 pounds. Instruments are for the pilot and 
should be located near that pilot's vertical plane of vision without 
regard to what flight rules are approved for the airplane's operation 
or the maximum weight of the airplane.

Section 23.1323  Airspeed Indicating System

    The proposed new Sec. 23.1323(c) would add a requirement that each 
airspeed indicating system design and installation should provide 
positive drainage of moisture from the system. This proposal is 
consistent with the provisions required for a static system by 
Sec. 23.1325(b).
    If moisture enters, or accumulates in, an airspeed indicating 
system, that moisture could cause erroneous airspeed indications or the 
complete loss of airspeed information. The resulting loss of accurate 
airspeed information would be hazardous to the operation of the 
airplane; therefore, to assure the safety of the airplane, the FAA 
would need to apply the more general airworthiness requirements of 
Secs. 23.1301 and 23.1309 to such a system and require provisions for 
drainage of moisture. Accordingly, this proposed revision of the 
airspeed indicating systems requirements only clarifies the criteria 
that must be applied to airspeed indicating systems.
    To better organize the requirements that are applicable to the 
airspeed systems on all airplane categories and those that would be 
additional requirements for the airspeed systems of commuter category 
airplanes, the FAA proposes to redesignate existing paragraphs (c) and 
(e), respectively, as paragraphs (e) and (d). By this redesignation, 
paragraphs (a), (b), (c), and (d) would apply to all airplanes, and 
paragraphs (e) and (f) would include additional requirements applicable 
to commuter category airplanes.
    The proposal for redesignated paragraph (e) would also remove the 
words ``in flight and'' from the first sentence of that paragraph. This 
would remove the requirement for the airspeed indicating system to be 
calibrated in flight. The requirement for an in flight calibration is 
provided in paragraph (b). Proposed redesignated paragraph (e) would 
apply to the calibration needed to determine the system error during 
the accelerate-takeoff ground run.
    As identified in the background section of this notice, the FAA is 
issuing additional notices that address proposed changes to the 
requirements for powerplant, flight, and airframe. Proposed revisions 
to subpart G in the flight NPRM include placing all of the requirements 
for what must appear in the Airplane Flight Manual (AFM) in that 
subpart. With the proposals to revise the AFM requirements, the flight 
NPRM also proposes that the requirement in existing Sec. 23.1323(d) (to 
show the relationship between IAS and CAS in the AFM) be added to 
Sec. 23.1587 as proposed new paragraph (d)(10). Because the AFM 
requirement would be added to Sec. 23.1587, it no longer needs to 
appear in Sec. 23.1323. Accordingly, this notice proposes to remove the 
text of existing Sec. 23.1323(d).
    Proposed new Sec. 23.1323(f) would provide that, on those commuter 
airplanes where duplicate airspeed indicators are required, the 
airspeed pitot tubes must be located far enough apart so that both 
tubes will not be damaged by a single bird strike.

Section 23.1325  Static Pressure System

    Current Sec. 23.1325(b)(3) establishes certain static pressure 
system requirements for airplanes that encounter icy conditions. 
Current Sec. 23.1325(g) exempts from the requirements of (b)(3) 
airplanes that are prohibited from flight in instrument meteorological 
conditions in accordance with Sec. 23.1559(b). After the adoption of 
Sec. 23.1325(g), it came to the FAA's attention that there are 
conditions other than instrument meteorological conditions where icing 
may be encountered and, therefore, that this paragraph should also 
exempt from the provisions of Sec. 23.1325(b)(3) airplanes that are 
prohibited from flight in icing conditions. Accordingly, 
Sec. 23.1325(g) would be revised to read, ``For airplanes prohibited 
from flight in instrument meteorological or icing conditions.''
    As indicated in the background section of this notice, the FAA will 
issue additional notices that will address proposed changes to the 
requirements for powerplant, flight, and airframe. Revisions to Subpart 
G in the flight notice will propose to place all of the requirements 
that specify what must appear in the AFM in that subpart. With the 
proposals to revise the AFM requirements, the flight notice will also 
propose that Sec. 23.1325(f) be removed and the results of the 
altimeter system calibration would be required by Sec. 23.1587.

Section 23.1326  Pitot Heat Indication System

    Proposed new Sec. 23.1326 would require the installation of a pitot 
tube heat indicating system on those airplanes required to be equipped 
with a heated pitot tube. Heated pitot tubes ensure that moisture will 
not freeze in the tube and block or partially block the airspeed 
indicating system. Such blockage would result in the pilots receiving 
incorrect flight data with possibly disastrous results.
    Due to advancements in technology, many part 23 airplane 
installations now utilize equipment whose data sources are critical to 
the accurate and dependable operation of that equipment. The heated 
pitot tube is one such data source. The pitot heat indicating system 
will advise the pilots of any inoperative heating element in the pitot 
tube and that subsequent inaccuracies may result.
    Part 23 airplanes certificated for flight under instrument flight 
rules or for flight in icing conditions are required by current 
Sec. 23.1323(e) to have a heated pitot system or an equivalent means of 
preventing an airspeed indicating system malfunction due to ice 
accumulation. This proposal would require such airplanes equipped with 
a heated pitot tube to be equipped with a pitot tube heat indicating 
system. This requirement will provide greater assurance that the pilots 
will not be dangerously misled by faulty flight instrument indications 
caused by pitot tube icing.
    When pitot tube heat indicating system requirements were added to 
part 25, the FAA noted the occurrence of at least one accident and 
several incidents in which an airspeed indicating error occurred that 
might have been avoided if a pitot tube heat indicating system had been 
installed. Part 23 airplanes operate at lower airspeeds and over 
shorter distances that do part 25 airplanes; therefore, their exposure 
to moisture and temperature conditions where icing may occur is higher 
than it is for transport category airplanes. Because of this 
environmental exposure, the potential for an inoperative heated pitot 
tube becoming a hazard to part 23 airplanes is greater.
    This proposed requirement also responds to National Transportation 
Safety Board (NTSB) recommendation A-92-85, which recommends requiring 
a modification to certain part 23 airplanes to provide for a pitot heat 
operating light similar to the light required by Sec. 25.1326 for 
transport category airplanes. NTSB issued the safety recommendation, 
among others, as a result of a special investigation and analysis of a 
series of fatal accidents that occurred from May 31, 1989, through 
March 17, 1991.

Section 23.1329  Automatic Pilot System

    New Sec. 23.1329(b), adopted by Amendment No. 23-24 (58 FR 18958, 
April 9, 1993), does not state clearly that stick controlled airplanes 
must be equipped with the same autopilot quick release controls that 
are required for airplanes with control wheels. This proposed revision 
of Sec. 23.1329(b) would clarify that a quick release control must be 
installed on each control stick of an airplane that can be operated 
from either pilot seat.

Section 23.1337  Powerplant Instruments Installation

    This proposal would revise the heading of this section to reflect 
the powerplant instrument installation requirements that it contains. 
The difference between this section and Sec. 23.1305 is clarified by 
this change.
    Section 23.1337(b) would be revised by removing the wording that 
authorizes installation of only those fuel indicators marked in gallons 
and pounds. In countries that use the metric system, other acceptable 
units of measure for marking fuel indicators are used. This proposed 
revision would allow the use of any appropriate measurement unit.
    Section 23.1337(b) would also be revised by adding the word 
``usable'' to the first sentence of this section. This revision is 
consistent with the requirements of Sec. 23.1337(b)(1), which requires 
the fuel quantity indicator to be calibrated to read ``zero'' when the 
fuel in the tank is equal to the unusable fuel determined under 
Sec. 23.959.
    Proposed new Sec. 23.1337(b)(4) would require a ``means to 
indicate'' the amount of usable fuel in each tank when the airplane is 
on the ground. This requirement would ensure that a reliable means is 
provided for the pilot to determine before takeoff that the amount of 
fuel that is in the airplane is adequate for the intended flight. The 
ability to make this preflight determination will help reduce the 
number of accidents that have resulted from fuel starvation. This 
proposal, which is patterned after Sec. 23.1337 (d) and (d)(1), would 
not require a separate fuel indicating system. The means to determine 
the amount of fuel while on the ground may be provided by a calibrated 
dipstick, separate markings on the inflight fuel indicator, or any 
other acceptable means selected by the manufacturer. Accordingly, this 
proposal would contribute to the safe operation of the airplane and 
would not appreciably add to the cost of the airplane design.

Section 23.1351  General

    The proposal would revise current Sec. 23.1351 by removing portions 
of paragraphs (b)(2) and (b)(3) and by removing all of paragraph 
(b)(4). The removed requirements are applicable to alternators that 
depend upon the battery for initial excitation or for stabilization. 
This revision responds to a Joint Aviation Authority recommendation to 
remove the provisions that allow a battery failure to result in the 
loss of the alternator. Information in this recommendation showed that 
self-excited alternators are now available for installation on newly 
certificated airplanes. The FAA has verified that self-excited 
alternators are now available; therefore, there is no longer a need for 
the regulations to address alternators that depend upon a battery for 
initial excitation and stabilization.
    Revised Sec. 23.1351(c)(3) would require an automatic means for 
reverse current protection. Reverse current protection is accomplished 
by means that automatically detect changes in the current. The proposed 
revised wording would more accurately define this function and the 
equipment that would accomplish the protection.
    Finally, Sec. 23.1351(f) would be revised by adding a requirement 
that would require the ground power receptacle to be located where its 
use will not result in a hazard to the airplane or to people on the 
ground using the receptacle.

Section 23.1353  Storage Battery Design and Installation

    Proposed new Sec. 23.1353(h) would require that, in the event of a 
complete loss of the primary electrical power generating system, 
airplane battery capacity must be sufficient to supply at least 30 
minutes of electrical power to those loads essential to the continued 
safe flight and landing of the airplane.
    This proposal is not limited to airplanes that are approved for any 
particular type of operation. Although the battery capacity needed for 
an airplane approved for day visual flight rules (VFR) operations would 
be much less than the capacity for an airplane approved for day/night 
instrument flight rules (IFR) operations, the same level of safety 
should be provided for all airplanes. While this proposal would add an 
additional requirement to part 23 for normal, utility, acrobatic, and 
commuter category airplanes, in practice this requirement to provide a 
battery capacity sufficient to supply at least 30 minutes of electrical 
power is not new to many airplane manufacturers. Certain other 
countries in which part 23 airplanes have been certificated have 
requirements for such a 30-minute battery capacity. Manufacturers' 
experience with these requirements has shown that the only design 
impact that results from complying with these requirements is the need 
to install a battery with greater capacity than might otherwise be 
installed. Experience has also shown that a load shedding procedure may 
be necessary for certain airplanes. No other airplane design changes 
would be needed.
    Despite the above referenced experience record, this requirement 
would be new to some manufacturers and they may have questions on how 
it would be applied. For that reason, this notice discusses compliance 
considerations that have emerged from experience based on substantively 
equivalent requirements.
    This compliance experience has shown that the rating of the battery 
selected for the airplane should be sufficient to cover the loss of 
capacity that would occur with battery age and the reduced capacity 
that results from a realistic state of charge, which may be less than a 
full charge. Using a design battery capacity that is only 75 percent of 
the battery nameplate rating would be an acceptable way of accounting 
for these losses.
    In addition to determining the battery rating that would be needed, 
the manufacturer would also need to determine the functions that would 
be necessary for 30 minutes of safe flight and the landing of the 
airplane. Again, experience has identified several functions. For a day 
VFR approved airplane, no functions may require battery power; however, 
it may be necessary to supply power for certain communication 
capacities or, if the airplane has electrically powered retractable 
landing gear, power may be required to lower the gear. Providing a 
secondary means for lowering the gear would be an acceptable 
alternative to providing electrical power or battery power for this 
function.
    For other types of operating approvals, providing power for the 
following functions and equipment should be considered:
    1. Any required flight and navigation instruments. Air driven 
instruments that would function over the required period can also be 
accepted for this function.
    2. Cockpit and instrument lighting.
    3. For IFR and icing approvals, power for the heated pitot tube.
    4. For radio communication, usually one VHF communication system 
with power for three to five minutes of transmission would be 
acceptable.
    5. Functions needed for safe night flight and night landing of the 
airplane.
    6. Electronic engine ignition systems.
    7. Any functions that cannot be readily shed following the loss of 
generator power.
    8. Engine inlet heat or deicing protection required for normal 
operation of the airplane.
    Although power for the listed functions may provide for the safe 
operation and landing of most airplanes, individual airplane designs 
may require the consideration of additional functions.
    In applying these rules it may be assumed that airframe and engine 
icing protection equipment would not be operating at the time of the 
generator system failure. Power for icing protection would not be 
required if the icing protection equipment is not required for the 
normal operation of the airplane.
    This proposal would require additional battery capacity and would 
not alter or supersede any other requirements in this part for separate 
or dedicated emergency power supplies. When requirements such as those 
in current Sec. 23.1331(a) or in proposed Sec. 23.1311(a)(5) are 
applicable to the airplane design, these power supplies are required to 
provide a needed level of safety for that function; therefore, that 
power source must be supplied.

Section 23.1359  Electrical System Fire Protection

    Proposed new Sec. 23.1359 would require smoke and fire protection 
for electrical system installations. The provisions of Sec. 23.1359(a) 
of this proposal state that electrical systems must meet the applicable 
requirements of Secs. 23.863 and 23.1182.
    Proposed Sec. 23.1359(b) would require that the electrical systems 
components installed in designated fire zones and used during emergency 
procedures be fire resistant. This provision is needed to clarify the 
requirements for electrical system components that may be installed in 
the designated fire zones identified in Sec. 23.1181.
    Finally, Sec. 23.1359(c) provides burn criteria for electrical wire 
and cables. A proposed revision to appendix F of part 23 that would add 
appropriate wire testing criteria is included in this notice.
    This proposed burn criteria for wire is necessary because of the 
increased use of electrical systems in the design of part 23 airplanes 
and the resulting increase in the amount of electrical wire being 
installed. This increased use results in the need to ensure that wire 
insulating material does not become the source of an in-flight fire 
and/or that it does not propagate a fire from another source. The 
electrical wire burn requirements in this proposal, along with the 
testing identified in revised appendix F, would ensure that installed 
electrical wire has insulating material that reduces the possibility of 
hazardous in-flight fires.

Section 23.1361  Master Switch Arrangement

    To harmonize with the JAR this proposal would revise 
Sec. 23.1361(c) by making an editorial change to remove the last two 
words of the paragraph that read ``in flight.''

Section 23.1365  Electrical Cables and Equipment

    This proposal would revise Sec. 23.1365(b) and would add three new 
paragraphs.
    Section 23.1365(b) would be revised in relation to proposed new 
Sec. 23.1359(c), which would require self-extinguishing insulated 
electrical wires and cables. Current Sec. 23.1365(b) requires that 
cable and associated equipment that would overheat in the event of 
circuit overload or fault must be flame resistant and may not emit 
dangerous quantities of toxic fumes. The proposed revisions to 
Sec. 23.1365(b) would remove the reference to electrical cables from 
the flame resistance requirement since the cables would be required to 
have self-extinguishing insulation under Sec. 23.1359(c). The 
requirement for electrical cables and the associated equipment that 
would overheat to not emit dangerous quantities of toxic fumes has been 
retained.
    The text of Sec. 23.1365(b) that includes the words ``at least 
flame resistant '' would also be revised by removing the words ``at 
least''. The removed words implied that there were burn requirements, 
other than the ones in this section, that must be met.
    The three paragraphs that would be added by this proposal would 
require: (1) The identification of electrical cables, terminals, and 
connectors; (2) the protection of electrical cables from damage by 
external sources; and (3) installation criteria for cables that cannot 
be protected by a circuit protection device.
    As identified in the discussion of proposed Sec. 23.1359, there is 
an increasing use of electrical systems in part 23 airplanes. The 
resulting increase in the number of electrical wires used in part 23 
airplanes makes proper installation difficult. The proposal for 
electrical cable identification would provide better assurance that the 
cables will be correctly installed initially and correctly reinstalled 
when airplane maintenance or modifications are accomplished. The other 
proposed new requirements would provide installation criteria that will 
ensure the protection of cables under circumstances that can be 
expected from the increased use of electrical systems.

Section 23.1383  Taxi and Landing Lights

    The landing light requirements of Sec. 23.1383 would be revised by 
adding taxi lights to this section. When the landing light requirements 
were included in the normal, utility, acrobatic, and commuter category 
requirements, the same lights were used for both night landing and 
taxiing of the airplane. Due to availability of different types of 
lights, separate lights are now frequently installed for landing and 
for taxiing. Including the word ``taxi'' in the heading would clarify 
that the requirements cover both kinds of lights.
    Current Sec. 23.1383(a), which requires the lights to be 
acceptable, would be deleted because it is unnecessary to state this. 
All lights that are found to meet the requirements of this section and 
other directly related airworthiness requirements are acceptable. The 
paragraphs would be redesignated accordingly.
    Current Sec. 23.1383(b)(3) requires that a landing light must be 
installed to provide enough light for a night landing. Proposed 
Sec. 23.1383(c) would revise ``night landing'' to ``night operation'' 
since the requirements would also cover taxiing and parking. Proposed 
new paragraph (d) would require the lights to be installed so that they 
do not cause a fire hazard. This clarifies the need for such an 
evaluation.

Section 23.1401  Anticollision Light System

    This proposal would revise Sec. 23.1401 to require the installation 
of an anticollision light system on all part 23 airplanes. Current 
Sec. 23.1401 requires an anticollision light system only if 
certification for night operations is requested. When the requirements 
for anticollision lights were first added to the Civil Air Regulations 
(CAR), part 3, in 1957, those requirements were needed to increase the 
conspicuity of the airplanes during night operations because of the 
increasing air traffic density and the newer airplanes' capability to 
attain higher speeds. At the time, the operating conditions did not 
show a need for such lights for daylight operations.
    The number of airplanes that have been added to the fleet and the 
increasing speeds resulting from improved technology, especially the 
increasing use of turbine engines, now necessitates the conspicuity 
provided by anticollision lights for day operations as well. The FAA 
Accident and Incident data for the period 1984 through 1990 shows that 
269 aircraft were involved in midair collisions in which 108 fatalities 
occurred. A review of this data shows that 234 of these aircraft were 
involved in accidents or incidents that occurred during VFR conditions 
and that 224 were involved in accidents or incidents during day 
operations. The other 10 were involved in operations at night or dusk. 
The reports on 35 aircraft did not identify the type of condition that 
existed.
    Of the types of aircraft identified by the reports in this data, 60 
were balloons, gliders, or other aircraft that were not certificated 
under part 23 and whose level of safety would not be changed by this 
proposal. When the data is revised by removing those reports, it shows 
that 209 small, part 23 airplanes operated under VFR conditions were 
involved in midair accidents or incidents and that at least 167 of 
these airplanes were being operated in day VFR conditions. Because the 
occupant capacity of all the aircraft in the data ranged from one to 
ten, it can be assumed that the fatality rate of .401 per aircraft (108 
fatalities/269 aircraft) would be nearly the same for the 167 small 
airplanes operating in day VFR conditions as it was for the 269 
aircraft. Based on this assumption, there would have been approximately 
67 fatalities that occurred in these 167 small airplane accidents and 
incidents.
    The reports do not show if the airplanes involved were equipped 
with or were using anticollision lights. They do show that a need 
exists to reduce the number of accidents. Requiring the installation of 
anticollision lights on all newly certificated airplanes and, as 
proposed by revised Sec. 91.209 in this notice, requiring operation of 
anticollision lights during day operations would increase the 
airplane's conspicuity and contribute to a reduction in the number of 
accidents. Even if such action is only 25 percent effective, a review 
of the 6-year service history indicates that approximately 17 
fatalities could be avoided in a similar 6-year period. Many 
manufacturers have realized the additional safety that can be provided 
by the increased airplane conspicuity of using anticollision lights and 
have elected to install an anticollision light system on all of the 
airplanes they produce. Therefore, most airplanes are now being 
manufactured with an installed anticollision light system, and the FAA 
expects that this proposal would not result in an economic burden on 
the aviation community.

Section 23.1431  Electronic Equipment

    This proposal would add three new paragraphs to Sec. 23.1431. 
Proposed new paragraph (c) would require that airplanes required to be 
operated by more than one flightcrew member must be evaluated to 
determine if the flightcrew members can converse without difficulty 
when they are seated at their duty stations. Accident investigations 
have shown that, in some instances, conversation between the flightcrew 
members was severely hindered by the noise level in the cockpit and 
that the inability to communicate contributed to the accident. If the 
required evaluation shows that the noise level does not impair 
conversation, no further action is required. However, if the evaluation 
shows that conversation will be difficult, an intercommunication system 
would be required.
    Proposed new paragraph (d) would require that if installed 
communication equipment includes any means of switching from receive to 
transmit, the equipment must use ``off-on'' transmitter switching that 
will ensure that the transmitter is turned off when it is not being 
used. Transmitting equipment that remains in the transmit mode when not 
being used blocks the frequency being used and can create an unsafe 
condition by preventing other needed communication.
    Proposed new paragraph (e) would require that if provisions for the 
use of communications headsets are provided, it must be demonstrated 
that flightcrew members can hear aural warnings when a headset is being 
used. Aural warnings are required to warn the pilot of a condition that 
necessitates the pilot's taking action; therefore, it is necessary to 
ensure that such warnings would be effective even when headsets are 
being used.
    During the development of the proposed new requirements in 
paragraphs (c) and (e), the FAA considered proposing a requirement that 
compliance demonstrations should be conducted under actual cockpit 
noise conditions when the airplane is being operated. The FAA, however, 
ultimately determined that such a requirement could result in 
demonstrations conducted under more severe noise conditions than 
needed. Accordingly, no such requirement is being proposed. If the FAA 
determines in the future that noise conditions for demonstrations need 
to be specified, the FAA will define these conditions in advisory 
material.

Section 23.1435  Hydraulic Systems

    Since the close of the comment period for the Small Airplane 
Airworthiness Review Program Notice No. 3 (55 FR 40598, October 3, 
1990), now adopted by Amendment No. 23-43 (58 FR 18958, April 9, 1993), 
the FAA has been involved in discussions of the installation of 
hydraulic accumulators that are permitted by Sec. 23.1435(c). These 
discussions have shown that applicants are likely to find 
Sec. 23.1435(c) difficult to understand because of the way it is 
worded. This notice would further revise Sec. 23.1435(c) to clarify 
under what circumstances a hydraulic accumulator and reservoir may be 
installed on the engine side of any firewall.

Section 23.1447  Equipment Standards for Oxygen Dispensing Units

    Proposed new Sec. 23.1447(a)(4) would require that if radio 
equipment is installed in an airplane, flightcrew oxygen dispensing 
units must be designed to allow the use of communication equipment when 
oxygen is being used. If radio equipment is installed, that equipment 
cannot perform its intended function if the flightcrew is not provided 
the proper means for its utilization under all operating conditions, 
including operations when oxygen is being used.
    This proposal would not require all flightcrew oxygen dispensing 
units to be equipped with communication equipment. Since an airplane 
may be operated in uncontrolled airspace, where two-way radio 
communication is not required and, at the same time, be at altitudes 
where oxygen is required for the flightcrew members, some airplanes 
have a crew oxygen system but no radio equipment. It would be 
inappropriate to require the flightcrew dispensing units of those 
airplanes to be equipped with communication equipment.
    The proposed revisions to Sec. 23.1447(d) would require the 
flightcrew oxygen dispensing units to be automatically presented before 
the cabin pressure altitude exceeds 15,000 feet or be the quick-donning 
type if the airplane is certificated for operation above 25,000 feet. 
The requirement in paragraph (e) for the passenger dispensing units to 
be automatically presented if the airplane is approved for operation 
above 30,000 feet has not been revised. The revision to paragraph (d) 
would provide the flightcrew and the airplane passengers the same level 
of safety as provided by other airworthiness standards. This proposed 
revision is also consistent with the proposed revision of Sec. 23.841 
in this notice.

Section 23.1451  Fire Protection for Oxygen Equipment

    This proposed new section would specify that fire protection is 
needed for oxygen equipment installations. Section 23.1451 (a) and (b) 
would, respectively, prohibit the installation of oxygen equipment in 
designated fire zones and require that oxygen system components be 
protected from the heat from designated fire zones.
    Proposed Sec. 23.1451(c) would require oxygen equipment and lines 
to be separated from other equipment or to be protected in a manner 
that would prevent escaping oxygen from striking grease, fluids, or 
vapors. The impingement of pure oxygen on certain materials will lower 
their combustion point to a value where ignition will occur in ambient 
conditions thereby creating a potential source for an airplane fire. In 
one instance, an airplane was destroyed by fire that resulted when 
escaping oxygen impinged on lubricating material during maintenance of 
the airplane. The proposed new section would ensure that oxygen systems 
are protected to prevent fire hazards that can result from escaping 
oxygen.

Section 23.1453  Protection of Oxygen Equipment From Rupture

    This proposed new section would clarify the rupture protection 
needed for oxygen system installation. Rupture protection for oxygen 
systems is currently required by the application of the structures load 
requirements of part 23. The addition of Sec. 23.1453(a) would clarify 
the application of these load requirements and would identify the need 
to consider maximum temperatures and pressures that may be present. 
Section 23.1453(b) would identify the protection to be provided for 
high pressure oxygen sources and the high pressure lines that connect 
such sources to the oxygen system shutoff valves.

Section 23.1461  Equipment Containing High Energy Rotors

    This proposal would revise paragraph (a) of this section to clarify 
that the requirements apply to high energy rotors included in an 
auxiliary power unit (APU). Following the addition of this section to 
part 23, the FAA issued a policy message that showed Sec. 23.1461 was 
adopted to cover equipment such as APU's and constant speed drives that 
may be installed on small airplanes. The proposed revision of paragraph 
(a) will clarify the applicability of this section as identified in 
that policy material.

Appendix F

    This proposal would revise appendix F to provide the procedures 
needed to test electrical wire to ensure that the wire meets the burn 
requirements of Sec. 23.1359. It would also add procedures for meeting 
the 45 degree and 60 degree angle burn test requirement proposed for 
Secs. 23.855(c)(2) and 23.1359(c), respectively. Paragraph (b) would be 
revised to clarify the specimen configuration that must be used in the 
testing procedures that are proposed to be added by this notice.

Section 91.205  Powered Civil Aircraft With Standard Category U.S. 
Airworthiness Certificates: Instrument and Equipment Requirements

    Proposed new Sec. 91.205(b)(11) would require that airplanes 
certificated under Sec. 23.1401 of this notice be equipped with an 
anticollision light system for day VFR operations. Day VFR operations 
are discussed under Sec. 23.1401 of this notice.

Section 91.209  Aircraft Lights

    Proposed new Sec. 91.209(b) would require that airplanes equipped 
with an anticollision light system be operated with the anticollision 
light system lighted during all types of operations, except when the 
pilot determines that, because of operating conditions, it would be in 
the interest of safety to turn the lights off.

Regulatory Evaluation, Regulatory Flexibility Determination, and Trade 
Impact Assessment

    Proposed changes to Federal regulations must undergo several 
economic analyses. First, Executive Order 12866 directs that each 
Federal agency shall propose or adopt a regulation only upon a reasoned 
determination that the benefits of the intended regulation justify its 
costs. Second, the Regulatory Flexibility Act of 1980 requires agencies 
to analyze the economic effect of regulatory changes on small entities. 
Third, the Office of Management and Budget directs agencies to assess 
the effects of regulatory changes on international trade. In conducting 
these analyses, the FAA has determined that this rule: (1) Would 
generate benefits that would justify its costs and is not a 
``significant regulatory action'' as defined in the Executive Order; 
(2) is not ``significant'' as defined in DOT's Policies and Procedures; 
(3) would not have a significant impact on a substantial number of 
small entities; and (4) would not constitute a barrier to international 
trade. These analyses, available in the docket, are summarized below.

Regulatory Evaluation Summary

    This section summarizes the costs and benefits of each provision of 
the proposed rule. Many of the provisions would impose either no cost 
or a negligible cost. Such provisions are typically administrative, 
editorial, clarifying, relieving, or conforming in nature. In addition, 
the FAA holds that certain provisions have a potential safety benefit 
that can be achieved with no incremental cost, due primarily to the 
fact that this rule would apply to future certificated airplanes and 
retrofitting would not be required. All provisions of the proposed 
rule, including those with no or negligible costs, are summarized 
below. Only those provisions with non-negligible costs are further 
evaluated in the section that follows. The reader is directed to the 
full regulatory evaluation for additional information.

----------------------------------------------------------------------------------------------------------------
               Section                           Incremental cost                          Benefit              
----------------------------------------------------------------------------------------------------------------
Section 23.677Trim systems...........  Negligible..........................  Safety.                            
Section 23.691 Artificial stall        None................................  Administrative.                    
 barrier system.                                                                                                
Section 23.697Wing flap controls.....  $480 per certification and $100 per   Nominal safety and relief.         
                                        airplane for affected airplanes.                                        
Section 23.701Flap interconnection...  None................................  Clarification.                     
Section 23.703Takeoff warning system.  $240 per certification for            Nominal safety and relief.         
                                        evaluation. Where necessary, $5,120                                     
                                        per certification, $1,000 per                                           
                                        airplane and $100 per year.                                             
Section 23.723Shock absorption tests.  None................................  Editorial.                         
Section 23.729Landing gear extension   (e). None..........................  Clarification.                     
 and retraction system.                                                                                         
                                       (g). Negligible, general practice..  Minor; general practice.           
Section 23.735Brakes.................  (a). None..........................  Editorial clarification.           
                                       (c). None..........................  Administrative.                    
                                       (e). $240 per certification........  Minor safety.                      
Section 23.745Nose/Tail wheel          None................................  Minor. Avoids special conditions.  
 steering.                                                                                                      
Section 23.775Windshields and windows  (a). None..........................  Relieving.                         
                                       (c). None..........................  Clarification.                     
                                       (h). Up to $350,000 per              Safety.                            
                                        certification.                                                          
Section 23.783Doors..................  (b). None..........................  Minor safety.                      
                                       (f). $25 per airplane..............  Safety.                            
Section 23.785Seats, births, litters,  None................................  Editorial organization.            
 safety belts and shoulder harnesses.                                                                           
Section 23.787Baggage and cargo        (a). $1 per airplane...............  Minor safety.                      
 compartments.                                                                                                  
                                       (b). $60 per certification and up    Safety.                            
                                        to $100 per airplane.                                                   
                                       (c). None..........................  Clarification.                     
Section 23.791Passenger information    $60 per certification, up to $200     Safety.                            
 signs.                                 per airplane, and a negligible                                          
                                        effect on operating costs.                                              
Section 23.807Emergency exits........  (a)(4). Expected negligible........  Minor safety.                      
                                       (b) and (b)(5). None...............  Clarification and editorial.       
                                       (b)(6). Where chosen, $10,000 per    Safety.                            
                                        certification and $500 per airplane.                                    
Section 23.841Pressurized cabins.....  $1,000 per certification and $2,000   Safety.                            
                                        per airplane.                                                           
Section 23.853Passenger and crew       None................................  Editorial.                         
 compartment interiors.                                                                                         
Section 23.855Cargo and baggage        (a). Less than $40 per airplane....  Minor safety.                      
 compartment fire protection.                                                                                   
                                       (b). Less than $200 per airplane...  Safety.                            
                                       (c). Potentially as high as $1,800   Safety.                            
                                        per certification, $4,550 per                                           
                                        airplane, and $100 per year.                                            
Section 23.867Electrical bonding and   None................................  Editorial.                         
 protection against lightning and                                                                               
 static electricity.                                                                                            
Section 23.1303Flight and navigation   Introduction. None..................  Clarification.                     
 instruments.                                                                                                   
                                       (d). $500 per certification and      Safety.                            
                                        $350 per airplane.                                                      
                                       (e)(2). None.......................  Minor safety.                      
                                       (f). None..........................  Minor safety.                      
                                       (g)(1). Up to $2,000 per airplane..  Safety.                            
                                       (g)(2). None.......................  Minor safety.                      
                                       (g)(3). Up to $3,600 per             Safety.                            
                                        certification and $7,000 per                                            
                                        airplane.                                                               
Section 23.1307Miscellaneous           None................................  Editorial and conforming.          
 equipment.                                                                                                     
Section 23.1309Equipment, systems,     None................................  Minor safety.                      
 and installations.                                                                                             
Section 23.1311Electronic display      None................................  Clarifying, editorial, and         
 instrument systems.                                                          relieving.                        
Section 23.1321Arrangement and         None................................  Minor safety.                      
 visibility.                                                                                                    
Section 23.1323Airspeed indicating     None................................  Minor safety.                      
 system.                                                                                                        
Section 23.1325Static pressure system  None................................  Relieving.                         
Section 23.1326Pitot heat indication   $2,800 per certification, $1,600 per  Safety.                            
 system.                                airplane.                                                               
Section 23.1329Automatic pilot system  None................................  Clarifying.                        
Section 23.1337Powerplant instruments  Heading and (b). None..............  Clarifying, relieving.             
 installation.                                                                                                  
                                       (b)(4). Negligible.................  Safety.                            
Section 23.1351General...............  (b). None..........................  Administrative.                    
                                       (c)(3). None.......................  Clarifying.                        
                                       (f). None..........................  Minor safety.                      
Section 23.1353Storage battery design  Where necessary, up to $30 per five   Safety.                            
 and installation.                      years capital, up to $10 per year                                       
                                        operating, and $600 per                                                 
                                        certification.                                                          
Section 23.1359Electrical system fire  (a). None..........................  Clarifying emphasis.               
 protection.                                                                                                    
                                       (b). Negligible....................  Clarifying.                        
                                       (c). $240 per certification........  Safety.                            
Section 23.1361Master switch           None................................  Editorial.                         
 arrangement.                                                                                                   
Section 23.1365Electrical cables and   (b). None..........................  Conforming editorial.              
 equipment.                                                                                                     
                                       (d). $4,400 per certification and    Safety.                            
                                        $100 per airplane.                                                      
                                       (e). None..........................  Minor safety.                      
                                       (f). Negligible....................  Minor safety.                      
Section 23.1383Taxi and landing        None................................  Editorial update.                  
 lights.                                                                                                        
Section 23.1401Anticollision light     Where necessary, $2,400 per           Safety.                            
 system.                                certification and $1,600 per                                            
                                        airplane.                                                               
Section 23.1431Electronic equipment..  (c). Where necessary, up to $1,200   Safety.                            
                                        per certification and $1,600 per                                        
                                        airplane.                                                               
                                       (d). Negligible. Included above....  Minor safety.                      
                                       (e). None or negligible............  Safety.                            
Section 23.1435Hydraulic systems.....  None................................  Clarifying.                        
Section 23.1447Equipment standards     (a)(4). Up to $2,000 per airplane..  Safety.                            
 for oxygen dispensing units.                                                                                   
                                       's (d) and (e). None...............  Minor safety.                      
Section 23.1451Fire protection for     None................................  Safety.                            
 oxygen equipment.                                                                                              
Section 23.1453Protection of oxygen    $960 per certification..............  Safety.                            
 equipment from rupture.                                                                                        
Section 23.1461Equipment containing    None................................  Clarifying.                        
 high energy rotors.                                                                                            
Appendix F to part 23--Test procedure  None. Considered above..............  Minor safety.                      
Section 91.205Powered civil aircraft   None................................  Safety, considered above.          
 with standard category U.S.                                                                                    
 airworthiness certificates:                                                                                    
 Instrument and equipment                                                                                       
 requirements.                                                                                                  
Section 91.209Aircraft lights........  $25 per year per airplane...........  Safety, considered above.          
----------------------------------------------------------------------------------------------------------------

Evaluation of Provisions With Non-Negligible Projected Costs

    This section describes and evaluates those provisions of the 
proposed rule that are expected to impose costs that are not 
negligible.

Section 23.697  Wing Flap Controls

    Proposed new Sec. 23.697(c) would provide safety standards for the 
wing flap control lever designs installed in airplanes that use wing 
flap settings other than fully retracted when showing compliance with 
Sec. 23.145. The FAA estimates that an aerospace engineer could design 
the flap control lever to meet the proposed requirement in 8 hours at a 
burdened rate of $60 per hour, totalling $480 per certification. The 
control lever itself would impose an incremental cost, including 
installation, of approximately $100 per airplane.
    The nominal benefits of this provision would derive from the 
increased safety afforded the pilot in positively selecting the proper 
flap setting to maintain longitudinal control. In fact, if a flap 
position other than fully retracted were needed to maintain 
longitudinal control: (1) That position would be necessary to prevent 
an unsafe condition, (2) the airplane would not be certificated under 
that design, and (3) the airplane would have to be redesigned so that 
intermediate flap positions would not be needed for control. Proposed 
paragraph (c) would allow the identification of an intermediate flap 
position and the positive means of selecting that position. This 
alternative would rectify the unsafe condition without requiring the 
manufacturer to redesign the airplane.

Section 23.703  Takeoff Warning System

    This proposed new section would require a takeoff warning system on 
some commuter category airplanes. The requirement would be applicable 
if the flight evaluation shows that an unsafe takeoff condition would 
result if lift devices or longitudinal trim devices are set to any 
position outside the approved takeoff range. If the evaluation shows 
that no unsafe condition would result at any setting of these devices, 
a takeoff warning system would not be required. For those airplanes on 
which a warning system must be installed, the proposed rule would 
provide requirements for the installation of the system.
    The FAA estimates that an evaluation to determine whether a takeoff 
warning system would be needed would cost $240 (4 hours of engineering 
at a burdened rate of $60 per hour). Where needed, the integration 
design of a warning system would cost $2,400 (40 hours at $60 per 
hour). In addition, an incremental 4 hours of flight testing at a cost 
of $2,720 ($500 per hour for two test pilots and $180 per hour for 
fuel) would be needed to demonstrate the system's performance. The FAA 
estimates that the system, including acquisition, wiring, micro 
switches, and labor, would add approximately $1,000 to the cost of each 
airplane required to have one. Maintenance of such a system would cost 
approximately $100 per year. The FAA solicits comments from interested 
parties concerning the expected certifications that would require a 
takeoff warning system and the concomitant costs to acquire, install, 
and maintain them.
    The nominal benefits of this proposal would derive from the 
increased safety provided by the takeoff warning system that would 
activate whenever lift or longitudinal trim devices are not set within 
their approved takeoff ranges. In fact, if an evaluation showed that 
positions of the lift or longitudinal trim devices could create an 
unsafe condition on takeoff, the manufacturer would be required, under 
existing regulations, to redesign the devices so that the unsafe 
positions could not be obtained. The proposed section would provide 
relief by allowing the applicant to install a warning system rather 
than redesigning the trim device(s).

Section 23.735  Brakes

    Proposed new Sec. 23.735(e), applicable to commuter category 
airplanes, would require establishing the minimum rejected takeoff 
brake kinetic energy capacity rating of each main wheel brake assembly. 
Section 23.45 provides that the determination of the accelerate-stop 
distance for commuter category airplanes be made in accordance with the 
applicant's procedures for operation in service. This proposed 
requirement is needed to ensure that the brakes will perform safely 
under accelerate-stop conditions.
    Under the proposed rule, manufacturers of commuter airplanes could 
determine the kinetic energy absorption requirements either through a 
conservative rational analysis of the sequence of events expected 
during a rejected takeoff or by using a formula presented in proposed 
new Sec. 23.735(e)(2). It is projected that the necessary determination 
would cost $240 based on four hours of engineering at a burdened rate 
of $60 per hour. The potential benefits of the proposal would derive 
from the added safety that would be provided by establishing beforehand 
the minimum necessary kinetic energy capacity rating of each main wheel 
brake assembly under rejected-takeoff conditions.

Section 23.775  Windshields and Windows

    Introductory text and paragraph (h)(1) would be added to require 
that commuter category windshield panes that are directly in front of 
the pilots be able to withstand the impact of a two pound bird at 
maximum approach flap speed. By requiring full protection against the 
strike of a two-pound bird at approach speed, additional protection 
would also be provided if the airplane strikes a larger bird or strikes 
a bird at a higher speed.
    Proposed Sec. 23.775(h)(2) would further require the panels of the 
windshield to be so arranged that, if one is damaged, other panels 
would remain to provide visibility for continuous safe flight and 
landing.
    The potential costs of proposed Sec. 23.775(h) would vary depending 
on the circumstances of the affected manufacturer. Industry sources 
estimate that the total nonrecurring cost per model would range from 
$250,000 to $350,000, consisting of: (1) Up to $200,000 for a bird 
strike test article (``bird gun'') if the manufacturer does not have 
one; and (2) up to $150,000 of time and materials costs for the actual 
testing.
    A manufacturer that has a bird strike test article would not incur 
additional capital test costs. Most manufacturers would incur up to 
$150,000 in time and materials costs for the actual testing, but even 
these costs would be mitigated by the existing need of most 
manufacturers to perform such tests for export sales to JAA member 
countries.
    Industry sources estimate that there would be no identifiable 
increment in design or tooling costs since the windshield would be an 
integral part of the initial design. Similarly, little or no recurring 
costs per airplane (incremental materials, installation, or weight) are 
projected since it is reasonable to assume that the pressure load, as 
compared to bird strike resistance, would be the controlling factor in 
the windshield design strength.
    The benefit of the proposed rule is the incremental protection 
against bird strikes that would be afforded to commuter category 
airplanes. The FAA has reviewed International Civil Aviation 
Organization (ICAO) data on bird strikes that occurred on member-
country airplanes of 19,000 pounds or less than 1981 through 1989. 
These data show that approximately 550 strikes occurred and that one 
out of seven strikes hit the windshield. The data show that:
    1. Almost 52 percent of the strikes occurred at altitudes of less 
than 100 feet, and 26.7 percent occurred between 101 and 1000 feet.
    2. Eighty-five percent of the strikes occurred at airspeeds of 150 
knots or less.
    3. Where bird types were reported, 27.6 percent of the strikes 
involved small birds and 58.6 involved medium size birds (2 pounds or 
less).
    4. Incidents where the airplane was damaged showed that 16.9 
percent resulted from small bird strikes and 64 percent resulted from 
medium size bird strikes.
    These data show that most bird strikes occur at takeoff and landing 
altitudes and airspeeds, and that birds weighing two pounds or less are 
struck most often. The standards of the proposed provision are based on 
these statistics. Few fatalities and injuries resulted from the bird 
strikes reported in the ICAO data. Similarly, a review of NTSB accident 
records between 1982 and 1992 revealed no U.S. accidents resulting from 
bird strikes to the windshields of commuter category airplanes. As a 
result, the FAA is not able to illustrate the justification of this 
provision on the basis of historical accidents. Instead, the standards 
are being proposed based on the expert recommendations of the ARAC. It 
is also noted that this standard will be applied in JAA member 
countries and that U.S. manufacturers wishing to export to those 
countries would be required to meet the standard in any event.
    Given that this provision cannot be quantitatively supported on the 
basis of past accidents alone, the FAA expressly requests public input 
and comments on its expected costs and potential benefits.

Section 23.783  Doors

    Proposed new paragraph (f) would require that the locks on lavatory 
doors, if installed, be designed so that they would not trap occupants. 
Lavatory door locks used in transport category airplanes (see 
Sec. 25.783) meet the requirements of this proposed rule. The FAA 
estimates that the incremental cost of this provision would be no more 
than $25 per lock. The proposal would reduce the likelihood that 
occupants would be trapped in a locked lavatory, both in emergency and 
non-emergency situations.

Section 23.787  Baggage and Cargo Compartments

    The proposed rule would extend to normal, utility, and acrobatic 
airplanes the existing commuter requirement to prevent baggage from 
hazardous shifting. The FAA estimates that an aerospace engineer would 
be required for 1 hour, at a burdened cost of $60 per hour, to analyze 
the subject loads that would need to be constrained. Tiedowns would 
cost approximately $50 per baggage compartment, or no more than $100 
per airplane. These additional costs would apply only to normal, 
utility, or acrobatic airplanes since commuter category airplanes are 
already subject to the requirement under the existing rule.
    The potential benefits of the proposed provision include the 
reduced likelihood: (1) That baggage compartments would be overloaded, 
(2) that stowed baggage would shift dangerously, and (3) that essential 
co-located equipment or wiring would be damaged.

Section 23.791  Passenger Information Signs

    This proposed new section would require at least one illuminated 
sign notifying all passengers when seat belts should be fastened. The 
requirement would apply only to airplanes where flightcrew members 
could not observe occupant seats or where the flightcrew compartment is 
separated from the passenger compartment. The signs would have to be 
legible to all seated passengers and be operable from a crewmember 
station.
    The FAA estimates that an aerospace engineer could design the 
required sign(s) in 1 hour, at a burdened rate of $60 per hour. The 
sign would cost approximately $200 per airplane, including parts and 
installation costs. Maintenance costs for bulb replacement would be 
negligible. The weight penalty associated with the light system would 
also be minor (no more than 2 pounds).
    The safety benefits of the proposed change would derive from the 
increased likelihood that passengers would know when their seat belts 
should be fastened.

Section 23.807  Emergency Exits

    Proposed new Sec. 23.807(a)(4) would provide the same hazard 
protection for a person using an emergency exit as that provided by 
proposed Sec. 23.783(b) for a person who uses a passenger door. 
Emergency exits could not be located with respect to a propeller disk 
or any other hazard in a manner that would endanger persons using that 
exit.
    The FAA holds that no incremental cost would be incurred to meet 
the standards of the proposed provision for newly certificated 
airplanes. However, this notice specifically requests that interested 
parties submit comments on the potential costs and methods of 
compliance that manufacturers would choose to comply with this proposed 
requirement.
    The proposed revision to Sec. 23.807(b)(5) would editorially revise 
the current egress requirements for acrobatic airplanes. New 
Sec. 23.807(b)(6) would establish similar egress standards for utility 
category airplanes that are certificated for spinning. Industry sources 
estimate that an aerobatic, quick-release door would cost an 
incremental $10,000 in engineering design per affected airplane model 
and an additional $500 per production airplane. Little or no additional 
weight is expected. These costs would apply only in cases where the 
manufacturer determines that the marketplace return of a combination 
type certificate would outweigh the additional costs of design and 
production.

Section 23.841  Pressurized Cabins

    The proposed revision to Sec. 23.841(a) would extend the cabin 
pressure requirements of current paragraph (a), which now apply to 
airplanes certificated for operation above 31,000 feet, to airplanes 
certificated for operation above 25,000 feet. Current part 25, JAR 25, 
and proposed JAR 23 include the same requirement proposed here. This 
proposed requirement is intended to protect airplane occupants from 
harm if a malfunction occurs at altitudes where symptoms of hypoxia 
occur, usually above 25,000 feet.
    For airplanes that will be certificated for maximum altitude 
operation between 25,000 feet and 31,000 feet, the proposal would 
necessitate two additional pressure altitude regulators and associated 
plumbing. Industry sources estimate that the proposed requirement would 
cost an incremental $1,000 in engineering design per affected airplane 
model and $2,000 per production airplane. Any additional weight would 
be negligible.
    The benefits of the proposal would derive from the incremental 
protection against hypoxia afforded to occupants of airplanes 
certificated for maximum altitude between 25,000 and 31,000 feet. Due 
to the increasing use of turbine engines, more part 23 airplanes are 
likely to be approved for operation above 25,000 feet. In the absence 
of this proposed rule, an increasing number of occupants would be 
exposed to the potential for harm in the event of a failure or 
malfunction of the pressure system on these airplanes.

Section 23.855  Cargo and Baggage Compartment Fire Protection

    Proposed paragraph (a) would require all sources of heat within 
each cargo and baggage compartment that are capable of igniting the 
compartment contents to be shielded and insulated to prevent such 
ignition. Existing Sec. 23.787(f) requires that cargo compartment lamps 
be installed so as to prevent contact between the lamp bulb and cargo. 
The proposal would clarify and extend this provision to include all 
sources of heat for baggage as well as cargo compartments.
    Lights and (rarely) heaters for pets are typically the only sources 
of heat located in a baggage or cargo compartment. A wire cage, costing 
no more than $20, around the heat source would meet these requirements. 
The FAA estimates that the cost of compliance per airplane would be no 
more than $40 in those rare cases where such protection would not have 
been provided anyway. The benefit of the proposed provision is a 
reduction in the possibility of fire caused by the ignition of 
compartment contents by lights or heaters.
    Proposed paragraph (b) would require cargo and baggage compartments 
to be constructed of materials that meet the appropriate provisions of 
Sec. 23.853(d)(3). Currently these requirements apply to commuter 
category airplanes and to the materials used in the compartments of 
these airplanes. The proposed new requirement would expand this 
applicability to the cargo and baggage compartments of all part 23 
airplanes. In effect, the proposed new requirement would require 
materials that are self-extinguishing rather than flame resistant as 
currently required under Sec. 23.787(d).
    Information provided by manufacturers shows that materials that 
meet self-extinguishing flame requirements are available at a slightly 
higher cost than materials that meet flame resistant requirements. The 
FAA conservatively estimates that the incremental costs of complying 
with proposed Sec. 23.855(b) would be less than $200 per airplane. The 
safety benefits of this provision would be an increase in cargo and 
baggage compartment fire protection.
    Proposed new paragraph (c) would add new fire protection 
requirements for cargo and baggage compartments for commuter category 
airplanes. The proposed rule would require one of the following three 
alternatives:
    (1) The compartment just be located where pilots seated at their 
duty station would easily discover the fire or the compartment must be 
equipped with a smoke or fire detector system to warn the pilot's 
station. The compartment must also be accessible for fire extinguisher 
application.
    (2) The compartment may be inaccessible, but must be equipped with 
a fire detector system that warns the pilot station, and the 
compartment must have ceiling and sidewall floor panels constructed of 
materials that have been subjected to and meet the vertical self-
extinguishing tests of appendix F to part 23.
    (3) The compartment must be constructed and sealed to contain any 
fire.
    The FAA cannot predict the designs of cargo and baggage compartment 
for future airplanes. If manufacturers choose to use smoke detectors, 
however, no more than 2 smoke detectors would be required per airplane. 
An aerospace engineer could determine the most appropriate location and 
design the smoke detector system in approximately 30 hours at a 
burdened rate of $60 per hour, for a total cost of $1,800 per 
certification. Two detectors, including wiring and installation, are 
estimated to cost about $4,550. Maintenance costs for the smoke 
detectors would cost approximately $100 per year. Materials that would 
meet the vertical self-extinguishing tests of appendix F (see option 2 
in the discussion above) would result in incremental costs of less than 
$200 per airplane.
    The FAA estimates that it would cost $500 to construct a sealed 
compartment, or a total of $1,000 for 2 compartments, if the 
manufacturer chooses that method of complying with the proposed 
requirement (see option 3 in the discussion above).
    Irrespective of the individual compliance method, the benefits of 
the proposed provision would come from the increased likelihood that a 
cargo or baggage compartment fire would either be extinguished or 
contained.

Section 23.1303  Flight and Navigation Instruments

    Revised Sec. 23.1303(d) would add the requirement for a free air 
temperature indicator for those airplanes whose performance must be 
based on weight, altitude, and temperature. This requirement already 
applies to turbine powered airplanes. The proposal would extend the 
requirement to reciprocating engine powered airplanes of more than 
6,000 pounds. Industry sources estimate that the proposed requirement 
would cost an incremental $500 in engineering design per affected 
airplane model and $350 per production airplane. Any additional weight 
would be negligible. The potential benefits of the proposal would 
accrue from the requirement that the information necessary to determine 
the performance envelope of the airplane be available to the pilot.
    Proposed Sec. 23.1303(g) would identify specific instruments, and 
limits of those instruments, required for commuter category airplanes. 
Proposed Sec. 23.1303(g)(1) states that if airspeed limitations vary 
with altitude, the airspeed indicators must show the variation of the 
maximum operating limit speed (VMO) with altitude. Industry 
sources indicate that an airspeed indicator with VMO ``pointer'' 
would cost $1,000 more than one without. Two airspeed indicators are 
required on commuter airplanes, therefore, the incremental cost of this 
requirement would be $2,000 per commuter category airplane produced. 
The potential safety benefit of the proposal would derive from the 
requirement that the information necessary to determine the maximum 
operating limit speed be available at all altitudes.
    Proposed Sec. 23.1303(g)(3) would require (for commuter category 
IFR-approved airplanes with passenger seating configurations of 10 
more) a third, independent, attitude indicator (AI). Industry sources 
estimate that an aerospace engineer could design and document a third 
attitude instrument system in 100 hours at a burdened rate of $60 per 
hour, totalling $6,000 per certification. It is estimated that an AI 
would cost approximately $8,000, including a standby battery, and that 
the installation would cost $2,200 for 40 hours of a mechanic's time at 
a burdened rate of $55 per hour. However, proposed Sec. 23.1311(a)(5), 
discussed below, would delete the requirement for a rate-of-turn 
indicator when an independent attitude indicator is installed. The 
costs associated with a rate-of-turn indicator include: 40 hours of 
design and documentation costs, $1,000 per indicator, and 40 hours of 
installation. Therefore, the incremental cost for an IFR-approved 
airplane with a passenger seating capacity of 10 or more would be 
$3,600 for 60 hours of engineering (100 hours for the AI, minus 40 
hours for the rate-of-turn indicator); $7,000 for the instrument 
($8,000 for the AI, minus $1,000 for the rate-of-turn indicator); and 
no additional cost for the installation (40 hours for the AI, minus 40 
hours for the rate-of-turn indicator).
    The potential safety benefits of a third, independent attitude 
indicator would derive from the reduced potential for erroneous 
attitude information. Currently, two attitude instruments are required 
for a ten passenger, IFR approved commuter category airplane. Service 
experience has shown that a failure can occur whereby an attitude 
indicator can appear to be working when it is actually providing 
incorrect information. During such a failure, pilots may have 
difficulty determining which instrument to follow, and hazardous flight 
attitudes may result. A third attitude indicator would allow the crew 
to retain reliable attitude information even in cases where one 
instrument is not operating correctly.

Section 23. 1326  Pitot Heat Indication System

    Proposed new G23.1326 would require the installation of a pitot 
tube heat indicating system on those airplanes required to be equipped 
with a heated pitot tube. Heated pitot tubes ensure that moisture will 
not freeze in the tube and block or partially block the airspeed 
system.
    A pitot heat indicating system, including an in-line current 
sensor, panel light, and associated wiring, would cost approximately 
$500. According to industry sources, an aerospace engineer could design 
and document such a system in 20 hours at a burdened rate of $60 per 
hour, totalling $1,200. A mechanic could install the system in 20 hours 
at a burden rate of $55 per hour, totalling $1,100. The estimated non-
recurring cost per certification, therefore, would total $2,800 ($1,200 
for design, $500 for the certification airplane's indicator, and $1,100 
for installation of that indicator). The estimated cost per production 
airplane would be $1,600 ($500 for the system and $1,100 for 
installation).
    The National Transportation Safety Board (NTSB) investigated a 
series of single model accidents that occurred between May 1989 and 
March 1991. During that period, five fatal accidents and a near fatal 
incident occurred in the United States. Two additional fatal accidents 
involving the same airplane model occurred in foreign countries. The 
NTSB's analysis indicated that four of the five U.S. accidents probably 
involved ice blockage of the pitot tubes because the pilots failed to 
activate pitot heat before flying into freezing instrument 
meteorological conditions. The Board recommended (A-92-86) that the FAA 
consider requiring a pitot heat operating light on small airplanes 
certificated to operate in icing conditions.
    A pitot heat indicating system would advise the pilots of any 
inoperative heating element in the pitot tube and that subsequent 
inaccuracies could result. The proposed provision would reduce the 
likelihood that pilots would rely on inaccurate airspeed information 
resulting from a blocked or partially blocked pitot tube.

Section 23.1353  Storage Battery Design and Installation

    Proposed new Sec. 23.1353(h) would require that, in the event of a 
complete loss of the primary electrical power generating system, 
airplane battery capacity must be sufficient to supply at least 30 
minutes of electrical power to those loads essential to the continued 
safe flight and landing of the airplane.
    In some cases, manufacturers may need to install larger batteries 
with greater capacities to comply with the proposed requirements. The 
FAA estimates that the size and capacity of a larger battery would add 
no more than a few pounds (incremental operating costs of less than $10 
per year) and $20 to $30 of additional cost for the battery.
    On some airplanes, a ``load shedding'' procedure, where the pilot 
would sequentially turn off certain equipment, could be required either 
in place of or in addition to a larger battery. The procedure would be 
provided in the pilot's operating handbook (POH). The FAA estimates 
that an aerospace engineer could establish a load shedding procedure in 
10 hours at a burdened rate of $60 per hour, for a total cost of $600 
per affected certification.
    Irrespective of the method of compliance, the proposal would 
increase the likelihood that sufficient electrical power would be 
available to safely land the airplane in the event of an electrical 
generating system failure.

Section 23.1359  Electrical System Fire Protection.

    Proposed Sec. 23.1359(c) would provide burn criteria for electrical 
wire and cables. A proposed revision to appendix F to part 23 would add 
appropriate wire testing criteria. Demonstrating and documenting that 
electrical wires and cables meet the requirements of this provision 
would take an aerospace engineer approximately 4 hours at a burdened 
rate of $60 per hour, for a total of $240 per certification. The 
requirement and testing criteria would increase the likelihood that 
necessary wires and cables would continue to function in the event of a 
fire.

Section 23.1365  Electrical Cables and Equipment

    Proposed Sec. 23.1365(d) would add a requirement for the 
identification of electrical cables, terminals, and connectors. 
Different colored wires and/or tags could be used in conjunction with a 
wiring diagram to identify the cables, terminals, and connectors. The 
FAA estimates that a draftsman could design and document this 
identification system in 80 hours at a burdened rate of $55 per hour, a 
total of $4,400 per certification. Incremental installation costs would 
be approximately $100 per airplane.
    The increasing use of electrical systems in part 23 airplanes has 
added to the difficultly of wiring installation. The proposed 
requirement for cable identification would increase the likelihood that 
cables would be correctly installed initially and would be correctly 
reinstalled as part of later maintenance or modification.

Section 23.1401  Anticollision Light System

    The proposal would revise Sec. 23.1401 to require the installation 
of an anticollision light system on all part 23 airplanes. Current 
Sec. 23.1401 requires an anticollision light system only if 
certification for night operations is requested. Many manufacturers 
currently install anticollision light systems on all airplanes they 
produce.
    Industry sources estimate that an aerospace engineer could design 
and document an anticollision light system in 40 hours at a burdened 
rate of $60 per hour, for a total of $2,400 per affected certification. 
The system would cost $500 and would take a mechanic approximately 20 
hours to install at a burdened rate of $55 per hour, a total of $1,600 
per affected airplane ($500 + (20 hours  x  $55 per hour) = $1,600). 
The weight penalty would be negligible. Only those future models that 
would not otherwise have anticollision light systems would actually 
incur incremental costs as a result of this provision.
    The number of airplanes that have been added to the small airplane 
fleet and the increasing speeds resulting from improved technology, 
especially turbine engines, warrant the use of anticollision lights for 
day operations as well as night. The FAA Accident and Incident data for 
the period 1984 through 1990 show that 269 aircraft were involved in 
midair collisions in which 108 fatalities occurred. When the data were 
filtered (to account for night operations, IFR conditions, and aircraft 
not affected by this proposal), it shows that at least 167 airplanes 
were involved in accidents or incidents that occurred in day VFR 
conditions. The reports do not reveal whether the airplanes were using 
anticollision lights at the time of the accident.
    The FAA holds that requiring the installation of anticollision 
lights on all newly certificated airplanes, and requiring their 
operation during day operations (as proposed by revised Sec. 91.209 and 
discussed later in this evaluation), would reduce the number of 
daylight, midair accidents. Even if the proposed requirement were only 
25 percent effective, the 6-year accident history indicates that 
approximately 17 fatalities could be avoided during a similar 6-year 
period.

Section 23.1431  Electronic Equipment

    This proposal would add three new paragraphs to Sec. 23.1431. 
Proposed new paragraph (c) would require that airplanes required to be 
operated by more than one flightcrew member must be evaluated to 
determine if the flightcrew members can converse without difficulty 
when they are seated at their duty stations. If the required evaluation 
shows that the noise level does not impair conversation, no further 
action would be required. If the evaluation shows that conversation 
would be difficult, however, an intercommunication system would be 
required.
    The FAA estimates that an evaluation of cockpit noise could be 
conducted in conjunction with other certification testing, therefore, 
no incremental costs are associated with the evaluation. An aerospace 
engineer could design an intercom system in 20 hours at a burdened rate 
of $60 per hour, for a total of $1,200 per affected certification. The 
FAA estimates that the addition of an intercom system would cost 
approximately $500 per airplane. A mechanic could install the system in 
approximately 20 hours at a burdened rate or $55 per hour. The total 
incremental production cost for an affected airplane, therefore, would 
be $1,600 ($500 + 20 hours  x  $55 per hour)).
    Proposed new paragraph (d) would require that if the communication 
equipment that is installed includes any means of switching from the 
receive mode to the transmit mode, the equipment must use ``off-on'' 
transmitter switching that turns the transmitter off when it is not 
being used. The cost of this feature is included in the $500 cost of 
the intercom, described above.
    NTSB investigation of at least two commuter accidents determined 
that excessive cockpit noise levels probably adversely affected the 
ability of the flight crews to communicate (Bar Harbor Airlines, Flight 
1808, August 25, 1985, 8 fatalities; and Henson Airlines, Flight 1517, 
September 23, 1985, 14 fatalities.)
    As a result, the Board recommended (A-86-113) that the FAA require 
the installation and use of crew interphone systems in the cockpit of 
airplanes operating under part 135. The benefit of the proposed 
requirement would derive from the increased likelihood that flightcrew 
members would be able to converse without difficulty and that the 
safety hazard of miscommunication would be reduced.

Section 23.1447  Equipment Standards for Oxygen Dispensing Units

    Proposed new Sec. 23.1447(a)(4) would require that if radio 
equipment is installed in an airplane, flightcrew oxygen dispensing 
units must be designed to allow use of the communication equipment when 
oxygen is being used.
    Industry sources estimate that an oxygen mask with an integral 
microphone costs $1,000 more than an oxygen mask without a microphone. 
The costs per affected airplane, therefore, would be $2,000 for two 
masks. The benefit of the proposed requirement is that it would allow 
flightcrew communication under all operating conditions, including 
operations when oxygen is required.

Section 23.1453  Protection of Oxygen Equipment From Rupture

    This proposed new section would clarify the rupture protection 
needed for oxygen system installation. Rupture protection for oxygen 
systems is currently required by the application of the structures load 
requirements of part 23. The addition of Sec. 23.1453(a) would clarify 
the application of these load requirements and would identify the need 
to consider maximum temperatures and pressures that may be present. 
Section 23.1453(b) would identify the protection to be provided for 
high pressure oxygen sources and the high pressure lines that connect 
these sources to the oxygen system shutoff valves.
    Industry sources estimate that an aerospace engineer could analyze 
and document the loads on each element of the oxygen system in 16 hours 
at a burdened rate of $60 per hour, for a total cost of $960. The 
routing of oxygen pressure sources and lines to protect them from 
unsafe temperatures and crash landings would be part of an airplane's 
basic design and would not impose incremental costs.

Section 91.209  Aircraft Lights

    Proposed new Sec. 91.209(b) would require airplanes equipped with 
an anticollision light system to operate those lights during all 
operations, including daytime VFR.
    The incremental cost of this provision would be incurred for light 
bulb replacement. The FAA estimates that a light bulb for an 
anticollision light system costs approximately $50 and that this 
provision would necessitate an incremental bulb replacement every two 
years. Accordingly, the cost is projected to equal $25 per year, per 
affected operating airplane.
    In summary, the FAA holds that the benefits of the proposed rule, 
though not directly quantifiable, would exceed the expected costs.

Regulatory Flexibility Determination

    The Regulator Flexibility Act of 1980 (RFA) was enacted by Congress 
to ensure that small entities are not unnecessarily or 
disproportionately burdened by Government regulations. The RFA requires 
a Regulatory Flexibility Analysis if a proposed rule would have a 
significant economic impact, either detrimental or beneficial, on a 
substantial number of small entities. FAA Order 2100.14A, Regulatory 
Flexibility Criteria and Guidance, establishes threshold cost values 
and small entity size standards for complying with RFA review 
requirements in FAA rulemaking actions. The proposed amendments would 
not have a significant economic impact on a substantial number of small 
entities.

Trade Impact Assessment

    The proposed rule would not constitute a barrier to international 
trade, including the export of American goods and services to foreign 
countries and the import of foreign goods and services into the United 
States. Instead, the proposed systems airworthiness standards would be 
harmonized with those of foreign aviation authorities and would lessen 
the restraints on trade.

Federalism Implications

    The regulations proposed herein would not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.

Conclusion

    The FAA proposes to revise the airworthiness standards to provide 
systems and equipment standards for normal, utility, acrobatic, and 
commuter airplanes that are the same as the standards that will be 
proposed for the same category airplanes by the Joint Aviation 
Authorities in Europe. If adopted, the proposed revision would reduce 
the regulatory burden on the United States and European airplane 
manufacturers by relieving them on the need to show compliance with 
different standards each time they seek certification approval of an 
airplane in a different country.
    For the reasons discussed in the preamble, and based on the 
findings in the Regulatory Evaluation, the FAA has determined that this 
proposed regulation is not significant under Executive Order 12866. In 
addition, the FAA certifies that this proposal, if adopted, will not 
have a significant economic impact, positive or negative, on a 
substantial number of small entities under the criteria of the 
Regulatory Flexibility Act. This proposal is not considered significant 
under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 
1979). An initial regulatory evaluation of the proposal has been placed 
in the docket. A copy may be obtained by contacting the person 
identified under FOR FURTHER INFORMATION CONTACT:

List of Subjects

14 CFR Part 23

    Aircraft, Aviation safety, Signs and symbols.

14 CFR Part 91

    Agriculture, Aircraft, Airmen, Airports, Air traffic control, 
Aviation safety, Canada, Cuba, Freight, Mexico, Noise control, 
Political candidates, Reporting and recordkeeping requirements, Safety, 
Smoking.

The Proposed Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration proposes to amend parts 23 and 91 of the Federal 
Aviation Regulations (14 CFR part 23 and 91) as follows:

PART 23--AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND 
COMMUTER CATEGORY AIRPLANES

    1. The authority citation for part 23 continues to read as follows:

    Authority: 49 U.S.C. app. 1344, 1354(a), 1355, 1421, 1423, 1425, 
1428, 1429, 1430; 49 U.S.C. 106(g).

    2. Section 23.677 is amended by revising paragraph (a) to read as 
follows:


Sec. 23.677  Trim systems.

    (a) Proper precautions must be taken to prevent inadvertent, 
improper, or abrupt trim tab operation. There must be means near the 
trim control to indicate to the pilot the direction of trim control 
movement relative to airplane motion. In addition, there must be means 
to indicate to the pilot the position of the trim device with respect 
to both the range of adjustment and, in the case of lateral and 
directional trim, the neutral position. This means must be visible to 
the pilot and must be located and designed to prevent confusion. The 
pitch trim indicator must be clearly marked with a position or range 
within which it has been demonstrated that take-off is safe for all 
center or gravity positions and each flap position approved for 
takeoff.
* * * * *
    3. A new Sec. 23.691 is added to read as follows:


Sec. 23.691  Artificial stall barrier system.

    If the function of an artificial stall barrier, for example, stick 
pusher, is necessary to show compliance with Sec. 23.201(c), the system 
must comply with the following:
    (a) With the system adjusted for operation, the plus and minus 
airspeeds at which downward pitching control will be provided must be 
established.
    (b) Considering the plus and minus airspeed tolerances established 
by paragraph (a) of this section, and airspeed must be selected for the 
activation of the downward pitching control that provides a safe margin 
above any airspeed at which any unsatisfactory stall characteristics 
occur.
    (c) In addition to the stall warning required by Sec. 23.207, a 
warning that is clearly distinguishable to the pilot under all expected 
flight conditions without requiring the pilot's attention, must be 
provided for faults that would prevent the system from providing the 
required pitching motion.
    (d) Each system must be designed so that the artificial stall 
barrier can be quickly and positively disengaged by the pilots to 
prevent unwanted downward pitching of the airplane by a quick release 
(emergency) control that meets the requirements of Sec. 23.1329(b).
    (e) A preflight check of the complete system must be established 
and the procedure for this check made available in the Airplane Flight 
Manual (AFM). Preflight checks that are critical to the safety of the 
airplane must be included in the limitations section of the AFM.
    (f) For those airplanes whose design includes an autopilot system:
    (1) A quick release (emergency) control installed in accordance 
with Sec. 23.1329(b) may be used to meet the requirements of paragraph 
(d) of this section, and
    (2) The pitch servo for that system may be used to provide the 
stall downward pitching motion.
    (g) In showing compliance with Sec. 23.1309, the system must be 
evaluated to determine the effect that any announced or unannounced 
failure may have on the continued safe flight and landing of the 
airplane or the ability of the crew to cope with any adverse conditions 
that may result from such failures. This evaluation must consider the 
hazards that would result from the airplane's flight characteristics if 
the system was not provided, and the hazard that may result from 
unwanted downward pitching motion, which could result from failures at 
airspeeds above the selected stall speed.
    4. Section 23.697 is amended by adding a new paragraph (c) to read 
as follows:


Sec. 23.697  Wing flap controls.

* * * * *
    (c) If compliance with Sec. 23.145(b)(3) necessitates wing flap 
retraction to positions that are not fully retracted, the wing flap 
control lever settings corresponding to those positions must be 
positively located such that a definite change of direction of movement 
of the lever is necessary to select settings beyond those settings.
    5. Section 23.701 is amended by revising paragraphs (a)(1) and 
(a)(2) to read as follows:


Sec. 23.701  Flap interconnection.

    (a) * * *
    (1) Be synchronized by a mechanical interconnection between the 
movable flap surfaces that is independent of the flap drive system; or 
by an approved equivalent means; or
    (2) Be designed so that the occurrence of any failure of the flap 
system that would result in an unsafe flight characteristic of the 
airplane is extremely improbable; or
* * * * *
    6. A new Sec. 23.703 is added to read as follows:


Sec. 23.703  Takeoff warning system.

    For commuter category airplanes, unless it can be shown that a lift 
or longitudinal trim device which affects the takeoff performance of 
the aircraft would not give an unsafe takeoff configuration when 
selected out of an approved takeoff position, a takeoff warning system 
must be installed and meet the following requirements:
    (a) The system must provide to the pilots an aural warning that is 
automatically activated during the initial portion of the takeoff roll 
if the airplane is in a configuration that would not allow a safe 
takeoff. The warning must continue until--
    (1) The configuration is changed to allow safe takeoff, or
    (2) Action is taken by the pilot to abandon the takeoff roll.
    (b) The means used to activate the system must function properly 
for all authorized takeoff power settings and procedures and throughout 
the ranges of takeoff weights, altitudes and temperatures for which 
certification is requested.


Sec. 23.723  [Amended]

    7. Section 23.723(b) is amended by changing the word ``reserved'' 
to ``reserve''.
    8. Section 23.729 is amended by revising paragraph (e) and by 
adding a new paragraph (g) to read as follows:


Sec. 23.729  Landing gear extension and retraction system.

* * * * *
    (e) Position indicator. If a retractable landing gear is used, 
there must be a landing gear position indicator (as well as necessary 
switches to actuate the indicator) or other means to inform the pilot 
that each gear is secured in the extended (or retracted) position. If 
switches are used, they must be located and coupled to the landing gear 
mechanical system in a manner that prevents an erroneous indication of 
either ``down and locked'' if each gear is not in the fully extended 
position, or of ``up and locked'' if each landing gear is not in the 
fully retracted position.
* * * * *
    (g) Equipment located in the landing gear bay. If the landing gear 
bay is used as the location for equipment other than the landing gear, 
that equipment must be designed and installed to minimize damage.

    9. Section 23.735 is amended by redesignating paragraph (c) as 
paragraph (d), by revising the introductory text of paragraph (a), and 
by adding new paragraphs (c) and (e) to read as follows:


Sec. 23.735  Brakes.

    (a) Brakes must be provided. The landing brake kinetic energy 
capacity rating of each main wheel brake assembly must not be less than 
the kinetic energy absorption requirements determined under either of 
the following methods:
* * * * *
    (c) During the landing distance determination required by 
Sec. 23.75, the pressure on the wheel braking system must not exceed 
the pressure specified by the brake manufacturer.
* * * * *
    (e) In addition, for commuter category airplanes, the rejected 
takeoff brake kinetic energy capacity rating of each main wheel brake 
assembly must not be less than the kinetic energy absorption 
requirements determined under either of the following methods--
    (1) The brake kinetic energy absorption requirements must be based 
on a conservative rational analysis of the sequence of events expected 
during a rejected takeoff at the design takeoff weight.
    (2) Instead of a rational analysis, the kinetic energy absorption 
requirements for each main wheel brake assembly may be derived from the 
following formula--

KE=0.0443 WV\2\/N
where,
KE=Kinetic energy per wheel (ft.-lbs.);
W=Design takeoff weight (lbs.);
V=Ground speed associated with the maximum value of V1 selected in 
accordance with Sec. 23.51(c)(1);
N=Number of main wheels with brakes.

    10. A new Sec. 23.745 is added to read as follows:


Sec. 23.745  Nose/tail wheel steering.

    (a) If nose/tail wheel steering is installed, it must be 
demonstrated that its use does not require exceptional pilot skill 
during takeoff and landing, in crosswinds and in the event of an engine 
failure; or its use must be limited to low speed maneuvering.
    (b) Movement of the pilot's steering control must not interfere 
with the retraction or extension of the landing gear.

    11. Section 23.775 is amended by revising paragraphs (a) and (c), 
by redesignating paragraph (d) as (e) and paragraph (e) as (d), by 
revising the newly designated paragraph (e), and by adding a new 
paragraph (h) to read as follows:


Sec. 23.775  Windshields and windows.

    (a) The internal panels of windshields and windows must be 
constructed of a nonsplintering material, such as nonsplintering safety 
glass.
* * * * *
    (c) On pressurized airplanes, if certification for operation up to 
and including 25,000 feet is requested, an enclosure canopy including a 
representative part of the installation must be subjected to special 
tests to account for the combined effects of continuous and cyclic 
pressurization loadings and flight loads, or compliance with the fail-
safe requirements of paragraph (d) of this section must be shown.
* * * * *
    (e) The windshield and side windows forward of the pilot's back 
when the pilot is seated in the normal flight position must have a 
luminous transmittance value of not less than 70 percent.
* * * * *
    (h) In addition, for commuter category airplanes, the following 
applies:
    (1) Windshield panes directly in front of the pilots in the normal 
conduct of their duties, and the supporting structures for these panes 
must withstand, without penetration, the impact of a two-pound bird 
when the velocity of the airplane (relative to the bird along the 
airplane's flight path) is equal to the airplane's maximum approach 
flap speed.
    (2) The windshield panels in front of the pilots must be arranged 
so that, assuming the loss of vision through any one panel, one or more 
panels remain available for use by a pilot seated at a pilot station to 
permit continued safe flight and landing.
    12. Section 23.783 is amended by revising paragraph (b) and by 
adding a new paragraph (g) to read as follows:


Sec. 23.783  Doors.

* * * * *
    (b) Passenger doors must not be located with respect to any 
propeller disk or any other potential hazard so as to endanger persons 
using that door.
* * * * *
    (g) If lavatory doors are installed, they must be designed to 
preclude an occupant from becoming trapped inside the lavatory. If a 
locking mechanism is installed, it must be capable of being unlocked 
from outside of the lavatory.
    13. Section 23.785 is amended by adding introductory text and by 
revising paragraph (b) to read as follows:


Sec. 23.785  Seats, berths, litters, safety belts and shoulder 
harnesses.

    There must be a seat or berth for each occupant that meets the 
following:
* * * * *
    (b) Each forward-facing or aft-facing seat/restraint system in 
normal, utility, or acrobatic category airplanes must consist of a 
seat, a safety belt, and a shoulder harness, with a metal-to-metal 
latching device as required by Sec. 23.1413, that are designed to 
provide the occupant protection provisions required in Sec. 23.562. 
Other seat orientations must provide the same level of occupant 
protection as a forward-facing or aft-facing seat with a safety belt 
and a shoulder harness, and must provide the protection provisions of 
Sec. 23.562.
* * * * *
    14. Section 23.787 is revised to read as follows:


Sec. 23.787  Baggage and cargo compartments.

    (a) Each baggage and cargo compartment must:
    (1) Be designed for its placarded maximum weight of contents and 
for the critical load distributions at the appropriate maximum load 
factors corresponding to the flight and ground load conditions of this 
part.
    (2) Have means to prevent the contents of any compartment from 
becoming a hazard by shifting, and to protect any controls, wiring, 
lines, equipment or accessories whose damage or failure would affect 
safe operations.
    (3) Have a means to protect occupants from injury by the contents 
of any compartment, located aft of the occupants and separated by 
structure, when the ultimate forward inertial load factor is 9g and 
assuming the maximum allowed baggage or cargo weight for the 
compartment.
    (b) Designs that provide for baggage or cargo to be carried in the 
same compartment as passengers must have a means to protect the 
occupants from injury when the baggage or cargo is subjected to the 
inertial loads resulting from the ultimate static load factors of 
Sec. 23.561(b)(3), assuming the maximum allowed baggage or cargo weight 
for the compartment.
    (c) For airplanes that are used only for the carriage of cargo, the 
flightcrew emergency exits must meet the requirements of Sec. 23.807 
under any cargo loading conditions.

    15. A new Sec. 23.791 is added to read as follows:


Sec. 23.791  Passenger information signs.

    For those airplanes in which the flightcrew members cannot observe 
the other occupants' seats or where the flightcrew members' compartment 
is separated from the passenger compartment, there must be at least one 
illuminated sign (using either letters or symbols) notifying all 
passengers when seat belts should be fastened. Signs that notify when 
seat belts should be fastened must:
    (a) When illuminated, be legible to each person seated in the 
passenger compartment under all probable lighting conditions; and
    (b) Be installed so that a flightcrew member can, when seated at 
the flightcrew member's station, turn the illumination on and off.

    16. Section 23.807 is amended by revising paragraphs (b) 
introductory text and (b)(5) and by adding new paragraphs (a)(4) and 
(b)(6) to read as follows:


Sec. 23.807  Emergency exits.

    (a) * * *
    (4) Emergency exits must not be located with respect to any 
propeller disk or any other potential hazard so as to endanger persons 
using that exit.
    (b) Type and operation. Emergency exits must be movable windows, 
panels, canopies, or external doors, openable from both inside and 
outside the airplane, that provide a clear and unobstructed opening 
large enough to admit a 19-by-26-inch ellipse. Auxiliary locking 
devices used to secure the airplane must be designed to be overridden 
by the normal internal opening means. The inside handles of emergency 
exits that open outward must be adequately protected against 
inadvertent operation. In addition, each emergency exit must--
* * * * *
    (5) In the case of acrobatic category airplanes, allow each 
occupant to abandon the airplane at any speed between VSO and 
VD; and
    (6) In the case of utility category airplanes certificated for 
spinning, allow each occupant to abandon the airplane at the highest 
speed likely to be achieved in the maneuver for which the airplane is 
certificated.
* * * * *


Sec. 23.841  [Amended]

    17. Section 23.841 is amended in paragraph (a) by removing the 
number ``31,000'' and replacing it with ``25,000''.
    18. Section 23.853 is amended by revising the section heading to 
read as follows:


Sec. 23.853  Passenger and crew compartment interiors.

* * * * *
    19. A new Sec. 23.855 is added to read as follows:


Sec. 23.855  Cargo and baggage compartment fire protection.

    (a) Sources of heat within each cargo and baggage compartment that 
are capable of igniting the compartment contents must be shielded and 
insulated to prevent such ignition.
    (b) Each cargo and baggage compartment must be constructed of 
materials that meet the appropriate provisions of Sec. 23.853(d)(3).
    (c) In addition for commuter category airplanes, each cargo and 
baggage compartment must:
    (1) Be located where the presence of a fire would be easily 
discovered by the pilots when seated at their duty station, or it must 
be equipped with a smoke or fire detector system to give a warning at 
the pilots' station, and provide sufficient access to enable a pilot to 
effectively reach any part of the compartment with the contents of a 
hand held fire extinguisher, or
    (2) Be equipped with a smoke or fire detector system to give a 
warning at the pilots' station and have ceiling and sidewall liners and 
floor panels constructed of materials that have been subjected to and 
meet the 45 degree angle test of Appendix F of this part. The flame may 
not penetrate (pass through) the material during application of the 
flame or subsequent to its removal. The average flame time after 
removal of the flame source may not exceed 15 seconds, and the average 
glow time may not exceed 10 seconds. The compartment must be 
constructed to provide fire protection that is not less than that 
required of its individual panels; or
    (3) Be constructed and sealed to contain any fire within the 
compartment.

    20. Section 23.867 is amended by revising the heading that precedes 
the section and the section heading to read as follows:

Electrical Bonding and Lightning Protection


Sec. 23.867  Electrical bonding and protection against lightning and 
static electricity.

* * * * *
    21. Section 23.1303 is amended by revising the introductory text; 
by amending paragraph (d) by inserting the words ``reciprocating 
engine-powered airplanes of more than 6,000 pounds maximum weight and'' 
between the words ``For'' and ``turbine''; by amending paragraph (e) 
concluding text by adding a line to read, ``The lower limit of the 
warning device must be set to minimize nuisance warning;'' at the end 
of the paragraph and by adding new paragraphs (f) and (g) to read as 
follows:


Sec. 23.1303  Flight and navigation instruments.

    The following are the minimum required flight and navigation 
instruments:
* * * * *
    (f) When an attitude display is installed, the instrument design 
must not provide any means, accessible to the flightcrew, of adjusting 
the relative positions of the attitude reference symbol and the horizon 
line beyond that necessary for parallax correction.
    (g) In addition, for commuter category air planes:
    (1) If airspeed limitations vary with altitude, the airspeed 
indicator must have a maximum allowable airspeed indicator showing the 
variation of VMO with altitude.
    (2) The altimeter must be a sensitive type.
    (3) Having a passenger seating configuration of 10 or more, 
excluding the pilot's seats and that are approved for IFR operations, a 
third attitude instrument must be provided that:
    (i) Is powered from a source independent of the electrical 
generating system;
    (ii) Continues reliable operation for a minimum of 30 minutes after 
total failure of the electrical generating system;
    (iii) Operates independently of any other attitude indicating 
system;
    (iv) Is operative without selection after total failure of the 
electrical generating system;
    (v) Is located on the instrument panel in a position acceptable to 
the Administrator that will make it plainly visible to and usable by 
any pilot at the pilot's station; and
    (vi) Is appropriately lighted during all phases of operation.


Sec. 23.1307  [Amended]

    22. Section 23.1307 is amended by removing paragraphs (a) and (b); 
and by removing the designation from paragraph (c).
    23. Section 23.1309 is amended by adding a new paragraph (a)(4) to 
read as follows:


Sec. 23.1309  Equipment, systems, and installations.

    (a) * * *
    (4) In a commuter category airplane, must be designed to safeguard 
against hazards to the airplane in the event of their malfunction or 
failure.
* * * * *
    24. Section 23.1311 is revised to read as follows:


Sec. 23.1311  Electronic display instrument systems.

    (a) Electronic display indicators, including those with features 
that make isolation and independence between powerplant instrument 
systems impractical, must:
    (1) Meet the arrangement and visibility requirements of 
Sec. 23.1321.
    (2) Be easily legible under all lighting conditions encountered in 
the cockpit, including direct sunlight, considering the expected 
electronic display brightness level at the end of an electronic display 
indicator's useful life. Specific limitations on display system useful 
life must be contained in the Instructions for Continued Airworthiness 
required by Sec. 23.1529.
    (3) Not inhibit the primary display of attitude, airspeed, 
altitude, or powerplant parameters needed by any pilot to set power 
within established limitations, in any normal mode of operation.
    (4) Not inhibit the primary display of engine parameters needed by 
any pilot to properly set or monitor powerplant limitations during the 
engine starting mode of operation.
    (5) Have an independent magnetic direction indicator and either an 
independent secondary mechanical altimeter, airspeed indicator, and 
attitude instrument or individual electronic display indicators for the 
altimeter, airspeed, and attitude indicator that are independent from 
the airplane's primary electrical power system. These secondary 
instruments may be installed in panel positions that are displaced from 
the primary positions specified by Sec. 23.1321(d), but must be located 
where they meet the pilots' visibility requirements of Sec. 23.1321(a).
    (6) Incorporate sensory cues for the pilot that are equivalent to 
those in the instrument being replaced by the electronic display 
indicators.
    (7) Incorporate visual displays of instrument markings, required by 
Secs. 23.1541 through 23.1553, or visual displays that alert the pilot 
to abnormal operational values or approaches to established limitation 
values, for each parameter required to be displayed by this part.
    (b) The electronic display indicators, including their systems and 
installations, and considering other airplane systems, must be designed 
so that one display of information essential for continued safe flight 
and landing will remain available to the crew, without need for 
immediate action by any pilot for continued safe operation, after any 
single failure or probable combination of failures.
    (c) As used in this section, ``instrument'' includes devices that 
are physically contained in one unit, and devices that are composed of 
two or more physically separate units or components connected together 
(such as a remote indicating gyroscopic direction indicator that 
includes a magnetic sensing element, a gyroscopic unit, an amplifier, 
and an indicator connected together). As used in this section, 
``primary'' display refers to the display of a parameter that is 
located in the instrument panel such that the pilot looks at it first 
when wanting to view that parameter.


Sec. 23.1321  [Amended]

    25. Section 23.1321 is amended by removing the words ``certificated 
for flight under instrument flight rules or of more than 6,000 pounds 
maximum weight'' from paragraph (d) introductory test.
    26. Section 23.1323 is amended by redesignating paragraph (c) as 
(e); by removing paragraph (d); by redesignating paragraph (e) as new 
paragraph (d); by removing the words ``in flight and'' from the first 
sentence of redesignated paragraph (e); and by adding new paragraphs 
(c) and (f) to read as follows:


Sec. 23.1323  Airspeed indicating system.

* * * * *
    (c) The design and installation of each airspeed indicating system 
must provide positive drainage of moisture from the pitot static 
plumbing.
* * * * *
    (f) For commuter category airplanes, where duplicate airspeed 
indicators are required, their respective pitot tubes must be far 
enough apart to avoid damage to both tubes in a collision with a bird.


Sec. 23.1325  [Amended]

    27. Section 23.1325 is amended by inserting the words ``or icing'' 
between the words ``meteorological'' and ``conditions'' in paragraph 
(g).
    28. A new Sec. 23.1326 is added to read as follows:


Sec. 23.1326  Pitot heat indication systems.

    If a flight instrument pitot heating system is installed to meet 
the requirements specified in Sec. 23.1323(d), an indication system 
must be provided to indicate to the flight crew when that pitot heating 
system is not operating. The indication system must comply with the 
following requirements:
    (a) The indication provided must incorporate an amber light that is 
in clear view of a flightcrew member.
    (b) The indication provided must be designed to alert the flight 
crew if either of the following conditions exist:
    (1) The pitot heating system is switched ``off''.
    (2) The pitot heating system is switched ``on'' and any pitot tube 
heating element is inoperative.


Sec. 23.1329  [Amended]

    29. Section 23.1329(b) is amended by adding the parenthetical 
phrase ``(both stick controls, if the airplane can be operated from 
either pilot seat)'' between the words, ``or on the stick control,'' 
and the word ``such''.
    30. Section 23.1337 is amended by revising the section heading, by 
revising the introductory text of paragraph (b), by redesignating 
paragraphs (b)(4) and (b)(5) as paragraph (b)(5) and (b)(6), 
respectively, and by adding a new paragraph (b)(4) to read as follows:


Sec. 23.1337  Powerplant instruments installation.

* * * * *
    (b) Fuel quantity indication. There must be a means to indicate to 
the flightcrew members the quantity of usable fuel in each tank during 
flight. An indicator calibrated in appropriate units and clearly marked 
to indicate those units must be used. In addition:
* * * * *
    (4) There must be a means to indicate the amount of usable fuel in 
each tank when the airplane is on the ground (such as by a stick 
gauge);
* * * * *
    31. Section 23.1351 is amended by removing paragraph (b)(4), by 
redesignating paragraphs (b)(5) as (b)(4), by adding a sentence to the 
end of paragraph (f) that reads, ``The external power connection must 
be located so that its use will not result in a hazard to the airplane 
or ground personnel'', and by revisiting paragraphs (b)(2), (b)(3), and 
(c)(3) to read as follows:


Sec. 23.1351  General.

* * * * *
    (b) * * *
    (2) Electric power source must function properly when connected in 
combination or independently.
    (3) No failure or malfunction of any electric power source may 
impair the ability of any remaining source to supply load circuits 
essential for safe operation.
* * * * *
    (c) * * *
    (3) Automatic means must be provided to prevent either damage to 
any generator/alternator or adverse effects on the airplane electrical 
system due to reverse current. A means must also be provided to 
disconnect each generator/alternator from the battery and other 
generators/alternators.
* * * * *
    32. Section 23.1353 is amended by adding a new paragraph (h) to 
read as follows:


Sec. 23.1353  Storage battery design and installation.

* * * * *
    (h) In the event of a complete loss of the primary electrical power 
generating system, the battery must be capable of providing at least 30 
minutes of electrical power to those loads that are essential to 
continue safe flight and landing. The 30 minute time period includes 
the time needed for the pilots to recognize the loss of generated power 
and take appropriate load shedding action.
    33. A new Sec. 23.1359 is added to read as follows:


Sec. 23.1359  Electrical system fire protection.

    (a) Each component of the electrical system must meet the 
applicable fire protection requirement of Secs. 23.863 and 23.1182.
    (b) Electrical cables, terminals, and equipment in designated fire 
zones that are used during emergency procedures must be fire-resistant.
    (c) Insulation on electrical wire and electrical cable must be 
self-extinguishing when tested at an angle of 60 degrees in accordance 
with the applicable portions of Appendix F of this part, or other 
approved equivalent methods. The average burn length must not exceed 3 
inches (76 mm) and the average flame time after removal of the flame 
source must not exceed 30 seconds. Drippings from the test specimen 
must not continue to flame for more than an average of 3 seconds after 
falling.


Sec. 23.1361  [Amended]

    34. Section 23.1361(c) is amended by removing the last two words 
``in flight''.
    35. Section 23.1365 is amended by revising paragraph (b) and by 
adding new paragraphs (d), (e), and (f) to read as follows:


Sec. 23.1365  Electrical cables and equipment.

* * * * *
    (b) Any equipment that is associated with any electrical cable 
installation and that would overheat in the event of circuit overload 
or fault must be flame resistant. The equipment and the electrical 
cables must not emit dangerous quantities of toxic fumes.
* * * * *
    (d) Means of identification must be provided for electrical cables, 
terminals, and connectors.
    (e) Electrical cables must be installed such that the risk of 
mechanical damage and/or damage caused by fluids, vapors, or sources of 
heat, is minimized.
    (f) Where a cable cannot be protected by a circuit protection 
device or other overload protection, it must not cause a fire hazard 
under fault conditions.
    36. Section 23.1383 is revised to read as follows:


Sec. 23.1383  Taxi and landing lights.

    Each taxi and landing light must be designed and installed so that:
    (a) No dangerous glare is visible to the pilots.
    (b) The pilot is not seriously affected by halation.
    (c) It provides enough light for night operations.
    (d) It does not cause a fire hazard in any configuration.
    37. Section 23.1401 is amended by revising the introductory text of 
paragraph (a) to read as follows:


Sec. 23.1401  Anticollision light system.

    (a) General. The airplane must have an anticollision light system 
that:
* * * * *
    38. Section 23.1431 is amended by adding new paragraphs (c), (d), 
and (e) to read as follows:


Sec. 23.1431  Electronic equipment.

* * * * *
    (c) For those airplanes required to have more than one flightcrew 
member, or whose operation will require more than one flightcrew 
member, the cockpit must be evaluated to determine if the flightcrew 
members, when seated at their duty station, can converse without 
difficulty. If the airplane design includes provision for the use of 
communication headsets, the evaluation must also consider conditions 
where headsets are being used. If the evaluation shows conditions under 
which it will be difficult to converse, an intercommunication system 
must be provided.
    (d) If installed communication equipment includes transmitter 
``off-on'' switching, that switching means must be designed to return 
from the ``transmit'' to the ``off'' position when it is released and 
ensure that the transmitter will return to the off (non transmitting) 
state.
    (e) If provisions for the use of communication headsets are 
provided, it must be demonstrated that the flightcrew members will 
receive all aural warnings when any headset is being used.
    39. Section 23.1435 is amended by revising paragraph (c) to read as 
follows:


Sec. 23.1435  Hydraulic systems.

* * * * *
    (c) Accumulators. A hydraulic accumulator or reservoir may be 
installed on the engine side of any firewall if--
    (1) It is an integral part of an engine or propeller system, or
    (2) The reservoir is nonpressurized and the total capacity of all 
such nonpressurized reservoirs is one quart or less.
    40. Section 23.1447 is amended by revising paragraphs (d) and (e) 
and by adding a new paragraph (a)(4) to read as follows:


Sec. 23.1447  Equipment standards for oxygen dispensing units.

* * * * *
    (a) * * *
    (4) If radio equipment is installed, the flightcrew oxygen 
dispensing units must be designed to allow the use of that equipment 
and to allow communication with any other required crew member while at 
their assigned duty station.
* * * * *
    (d) For a pressurized airplane designed to operate at flight 
altitudes above 25,000 feet (MSL), the dispensing units must meet the 
following:
    (1) The dispensing units for passengers must be connected to an 
oxygen supply terminal and be immediately available to each occupant 
wherever seated.
    (2) The dispensing units for crewmembers must be automatically 
presented to each crewmember before the cabin pressure altitude exceeds 
15,000 feet, or the units must be of the quick-donning type, connected 
to an oxygen supply terminal that is immediately available to 
crewmembers at their station.
    (e) If certification for operation above 30,000 feet is requested, 
the dispensing units for passengers must be automatically presented to 
each occupant before the cabin pressure altitude exceeds 15,000 feet.
* * * * *
    41. A new Sec. 23.1451 is added to read as follows:


Sec. 23.1451  Fire protection for oxygen equipment.

    Oxygen equipment and lines must:
    (a) Not be installed in any designated fire zones.
    (b) Be protected from heat that may be generated in, or escape 
from, any designated fire zone.
    (c) Be installed so that escaping oxygen cannot come in contact 
with and cause ignition of grease, fluid, or vapor accumulations that 
are present in normal operation or that may result from the failure or 
malfunction of any other system.
    42. A new Sec. 23.1453 is added to read as follows:


Sec. 23.1453  Protection of oxygen equipment from rupture.

    (a) Each element of the oxygen system must have sufficient strength 
to withstand the maximum pressure and temperature, in combination with 
any externally applied loads arising from consideration of limit 
structural loads, that may be acting on that part of the system.
    (b) High pressure oxygen sources and the lines between the source 
and the shutoff means must be:
    (1) Protected from unsafe temperatures; and
    (2) Located where the probability and hazard of rupture in a crash 
landing are minimized.
    43. Section 23.1461 is amended by revising paragraph (a) to read as 
follows:


Sec. 23.1461  Equipment containing high energy rotors.

    (a) Equipment, such as Auxiliary Power Units (APU) and constant 
speed drive units, containing high energy rotors must meet paragraphs 
(b), (c), or (d) of this section.
* * * * *
    44. Appendix F to part 23 is amended by revising the introductory 
paragraph, by amending paragraph (c) to change the reference from 
paragraph (e) to paragraph (g), by amending paragraph (d) to change the 
reference from paragraph (f) to paragraph (h), by redesignating current 
paragraph (f) as paragraph (h), and by revising paragraph (b) and 
adding new paragraphs (f) and (g) to read as follows:

Appendix F to Part 23--Test Procedure

    An acceptable test procedure for self-extinguishing materials for 
showing compliance with Secs. 23.853, 23.855 and 23.1359.
* * * * *
    (b) Specimen configuration. Except as provided for materials used 
in electrical wire and cable insulation and in small parts, materials 
must be tested either as a section cut from a fabricated part as 
installed in the airplane or as a specimen simulating a cut section, 
such as: a specimen cut from a flat sheet of the material or a model of 
the fabricated part. The specimen may be cut from any location in a 
fabricated part; however, fabricated units, such as sandwich panels, 
may not be separated for a test. The specimen thickness must be no 
thicker than the minimum thickness to be qualified for use in the 
airplane, except that: (1) Thick foam parts, such as seat cushions, 
must be tested in \1/2\-inch thickness; (2) when showing compliance 
with Sec. 23.853(d)(3)(v) for materials used in small parts that must 
be tested, the materials must be tested in no more than \1/8\-inch 
thickness; (3) when showing compliance with Sec. 23.1359(c) for 
materials used in electrical wire and cable insulation, the wire and 
cable specimens must be the same size as used in the airplane. In the 
case of fabrics, both the warp and fill direction of the weave must be 
tested to determine the most critical flammability conditions. When 
performing the tests prescribed in paragraphs (d) and (e) of this 
appendix, the specimen must be mounted in a metal frame so that (1) in 
the vertical tests of paragraph (d) of this appendix, the two long 
edges and the upper edge are held securely; (2) in the horizontal test 
of paragraph (e) of this appendix, the two long edges and the edge away 
from the flame are held securely; (3) the exposed area of the specimen 
is at least 2 inches wide and 12 inches long, unless the actual size 
used in the airplane is smaller; and (4) the edge to which the burner 
flame is applied must not consist of the finished or protected edge of 
the specimen but must be representative of the actual cross section of 
the material or part installed in the airplane. When performing the 
test prescribed in paragraph (f) of this appendix, the specimen must be 
mounted in a metal frame so that all four edges are held securely and 
the exposed area of the specimen is at least 8 inches by 8 inches.
* * * * *
    (f) Forty-five degree test. A minimum of three specimens must be 
tested and the results averaged. The specimens must be supported at an 
angle of 45 degrees to a horizontal surface. The exposed surface when 
installed in the aircraft must be face down for the test. The specimens 
must be exposed to a Bunsen or Tirrill burner with a nominal \3/8\-inch 
I.D. tube adjusted to give a flame of 1\1/2\ inches in height. The 
minimum flame temperature measured by a calibrated thermocouple 
pyrometer in the center of the flame must be 1550  deg.F. Suitable 
precautions must be taken to avoid drafts. The flame must be applied 
for 30 seconds with one-third contacting the material at the center of 
the specimen and then removed. Flame time, glow time, and whether the 
flame penetrates (passes through) the specimen must be recorded.
    (g) Sixty-degree test. A minimum of three specimens of each wire 
specification (make and size) must be tested. The specimen of wire or 
cable (including insulation) must be placed at an angle of 60 degrees 
with the horizontal in the cabinet specified in paragraph (c) of this 
appendix, with the cabinet door open during the test or placed within a 
chamber approximately 2 feet high x 1 foot x 1 foot, open at the top 
and at one vertical side (front), that allows sufficient flow of air 
for complete combustion but is free from drafts. The specimen must be 
parallel to and approximately 6 inches from the front of the chamber. 
The lower end of the specimen must be held rigidly clamped. The upper 
end of the specimen must pass over a pulley or rod and must have an 
appropriate weight attached to it so that the specimen is held tautly 
throughout the flammability test. The test specimen span between lower 
clamp and upper pulley or rod must be 24 inches and must be marked 8 
inches from the lower end to indicate the central point for flame 
application. A flame from a Bunsen or Tirrill burner must be applied 
for 30 seconds at the test mark. The burner must be mounted underneath 
the test mark on the specimen, perpendicular to the specimen and at an 
angle of 30 degrees to the vertical plane of the specimen. The burner 
must have a nominal bore of three-eighths inch, and must be adjusted to 
provide a three-inch-high flame with an inner cone approximately one-
third of the flame height. The minimum temperature of the hottest 
portion of the flame, as measured with a calibrated thermocouple 
pyrometer, may not be less than 1,750  deg.F. The burner must be 
positioned so that the hottest portion of the flame is applied to the 
test mark on the wire. Flame time, burn length, and flaming time of 
drippings, if any, must be recorded. The burn length determined in 
accordance with paragraph (h) of this appendix must be measured to the 
nearest one-tenth inch. Breaking of the wire specimen is not considered 
a failure.
* * * * *

PART 91--GENERAL OPERATING AND FLIGHT RULES

    45. The authority citation for part 91 continues to read as 
follows:

    Authority: 49 U.S.C. 1301(7), 1303, 1344, 1348, 1352 through 
1355, 1401, 1421 through 1431, 1471, 1472, 1502, 1510, 1522, and 
2121 through 2125; Articles 12, 29, 21, and 32(a) of the Convention 
on International Civil Aviation (61 Stat. 1180); 42 U.S.C. 4321 et 
seq.; E.O. 11514; 49 U.S.C. 106(g).

    46. Section 91.205 is amended by redesignating paragraphs (b)(11) 
through (b)(16) as paragraphs (b)(12) through (b)(17), respectively, 
and by adding a new paragraph (b)(11) to read as follows:


Sec. 91.205  Powered civil aircraft with standard category U.S. 
airworthiness certificates: Instrument and equipment requirements.

* * * * *
    (b) * * *
    (11) For small civil airplanes certificated after [INSERT DATE OF 
THIS AMENDMENT], in accordance with part 23, as amended by amendment 
23-[INSERT AMENDMENT NUMBER], an approved aviation red or aviation 
white anticollision light system. In the event of failure of any light 
of the anticollision light system, operation of the aircraft may 
continue to a location where repairs or replacement can be made.
* * * * *


47. Section 91.209 is revised to read as follows:

Sec. 91.209  Aircraft lights.

    No person may:
    (a) During the period from sunset to sunrise (or, in Alaska, during 
the period a prominent unlighted object cannot be seen from a distance 
of 3 statute miles or the sun is more than 6 degrees below the 
horizon)--
    (1) Operate an aircraft unless it has lighted position lights;
    (2) Park or move an aircraft in, or in dangerous proximity to, a 
night flight operations area of an airport unless the aircraft--
    (i) Is clearly illuminated;
    (ii) Has lighted position lights; or
    (iii) Is in an area that is marked by obstruction lights;
    (3) Anchor an aircraft unless the aircraft--
    (i) Has lighted anchor lights; or
    (ii) Is in an area where anchor lights are not required on vessels; 
or
    (b) Operate an aircraft that is equipped with an anticollision 
light system, unless it has lighted anticollision lights. However, the 
anticollision lights need not be lighted when the pilot-in-command 
determines that, because of operating conditions, it would be in the 
interest of safety to turn the lights off.

    Issued in Washington DC on July 14, 1994.
Thomas E. McSweeny,
Director, Aircraft Certification Service.
[FR Doc. 94-17798 Filed 7-21-94; 8:45 am]
BILLING CODE 4910-13-M