[Federal Register Volume 61, Number 233 (Tuesday, December 3, 1996)]
[Proposed Rules]
[Pages 64230-64240]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-30365]



[[Page 64229]]

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Part IV

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Department of Transportation





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Federal Aviation Administration



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14 CFR Part 135



Commercial Passenger-Carrying Operations in Single-Engine Aircraft 
under Instrument Flight Rules; Proposed Rule

  Federal Register / Vol. 61, No. 233 / Tuesday, December 3, 1996 / 
Proposed Rules  

[[Page 64230]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 135

[Docket No. 28743; Notice No. 96-14]
RIN 2120-AG22


Commercial Passenger-Carrying Operations in Single-Engine 
Aircraft under Instrument Flight Rules

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of Proposed Rulemaking.

-----------------------------------------------------------------------

SUMMARY: The Federal Aviation Administration (FAA) is proposing to 
revise the conditions and limitations in Part 135 for instrument flight 
rule (IFR), passenger-carrying operations in single-engine aircraft. 
The proposed rule will expand the passenger-carrying provisions of the 
current rule, add equipment requirements, as well as maintenance 
requirements to monitor engine reliability, and delete the limited IFR 
provisions of the existing rule for both single and multi-engine 
aircraft. Currently, operation of single-engine aircraft carrying 
passengers is authorized for visual flight rules (VFR) or for limited 
operations in instrument meteorological conditions (IMC). Single-engine 
cargo operations are authorized to operate under IFR without these 
limitations. VFR flight into IMC is the most significant cause of fatal 
accidents in Alaska and is a serious problem for single-engine aircraft 
nationally. This action would increase the safety of single-engine, 
passenger-carrying operations by allowing planned instrument flight in 
the IFR system and by imposing certain other conditions and 
limitations.

DATES: Comments must be received by February 3, 1997.

ADDRESSES: Comments on this notice should be submitted in triplicate 
to: Federal Aviation Administration, Office of the Chief Counsel, Attn: 
Rules Docket (AGC-200), Room 915-G, Docket No. 28743, 800 Independence 
Ave., SW, Washington, DC 20591. Comments must be marked Docket No. 
28743. Comments also may be submitted electronically to the following 
Internet address: [email protected]. Comments may be examined in 
room 915G weekdays between 8:30 a.m. and 5 p.m. except on Federal 
holidays.

FOR FURTHER INFORMATION CONTACT:
Ms. Katherine Hakala, Flight Standards Service, Federal Aviation 
Administration, 800 Independence Ave, SW, Washington, DC 20591 (202) 
267-8166/3760.

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, 
federal, or economic impact that might result from adopting the 
proposals in this notice are also invited. Substantive comments should 
be accompanied by cost estimates, if appropriate. 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 dates for comments, in the Rules 
Docket, for examination by interested persons. A report summarizing 
each substantive contact with FAA personnel concerned with this 
rulemaking 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 pre-addressed, stamped postcard on which the 
following statement is made: ``Comments to Docket No. 28743.'' The 
postcard will be date stamped and returned to the commenter.

Availability of NPRMs

    An electronic copy of this document may be downloaded, using a 
modem and suitable communications software, from the FAA regulations 
section of the Fedworld electronic bulletin board service ((703) 321-
3339), the Federal Register's electronic bulletin board service ((202) 
512-1661), or the FAA's Aviation Rulemaking Advisory Committee Bulletin 
Board service ((800) 322-2722 or (202) 267-5948).
    Internet users may reach the FAA's web page at http://www.faa.gov 
or the Federal Register's web page a http://www.access.gpo.gov/su__docs 
for access to recently published rulemaking documents.
    Any person may obtain a copy of this NPRM by submitting a request 
to the Federal Aviation Administration, Office of Rulemaking, ARM-1, 
800 Independence Ave, SW, Washington, DC 20591, or by calling (202) 
267-9677. Communications must identify the notice number or docket 
number of this NPRM.
    Persons interested in being placed on the mailing list for future 
NPRMs 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.

Rationale

    In the past, the rationale against single-engine IFR passenger-
carrying operations centered on the hazards of losing an engine. 
Analysis indicates, however, a far more significant accident category: 
flight under visual flight rules (VFR) into instrument meteorological 
conditions (IMC). A recent NTSB study of aviation in Alaska indicated 
that VFR flight into IMC caused a disproportionate number of fatal 
accidents in part 135 operations in that state. Multi-engine airplanes 
are able to file and fly with passengers under IFR, while single-engine 
airplanes are only able (with few exceptions) to carry passengers under 
VFR. Thus, multi-engine airplanes have the advantage of contact with 
ATC, position following, en route and terminal weather information, and 
the higher altitude ensuring obstacle clearance and radio reception in 
the IFR system. The FAA Administrator, in a November 18, 1994, letter 
to pilots (``Winter Operations Emphasis Program 1994,'' available in 
the docket), expressed his concern about the number of accidents that 
occur when pilots are flying just below a low ceiling and collide with 
the terrain. He stated that one of the safest steps available was to 
take advantage of the IFR system. Aircraft flying at published cruising 
altitude that guarantees obstacle clearance and radio reception have 
considerably more time to glide to a landing and maneuver to a safe 
landing area than those flying below the ceiling.
    The number of accidents involving VFR flight into IMC is 
substantial. It is concern with this safety hazard that prompted the 
FAA to reconsider its limitations on single-engine IFR flight with 
passengers under part 135. Additionally, the FAA has considered the 
action of Canada that allowed single-engine passenger-carrying IFR 
under certain conditions, and the petitions for exemption of the Alaska 
Air Carrier Association and individual operators. While this action 
will not eliminate VFR flight into IFR conditions accidents, it is 
expected that it will reduce the accident rate.

Background

    Prior to October 10, 1978, passenger-carrying, single-engine 
instrument flight rule (SEIFR) operations were permitted

[[Page 64231]]

if an aircraft could descend to VFR conditions in the event of an 
engine failure. This provision allowed operations in IMC or over-the-
top of a ceiling, as long as VFR conditions existed below that ceiling 
(i.e., a buffer zone). In 1978, part 135 was substantially revised for 
passenger-carrying operations over the top or in IFR conditions to 
require an aircraft to be able to descend under VFR if its engine fails 
(43 FR 46742, October 10, 1978). This revision also provided for 
``limited IFR'' operations which, if VFR conditions were forecast 
within 15 minutes flying time, allowed flight in IMC for the first 15 
minutes of flight, and thereafter only if those IFR conditions were 
unforecast. The pilot can operate in IFR conditions if unforecast 
weather conditions are encountered while en route on a flight planned 
to be conducted under VFR. The pilot can make an IFR approach at the 
destination airport if unforecast weather conditions are encountered 
that do not allow an approach under VFR. This rule had the effect of 
eliminating the buffer zone provisions, restricting planned flights 
under IFR in IMC, and restricting VFR over-the-top flights to scattered 
or broken sky conditions. An exception to the two-pilot requirement, or 
autopilot requirement, is provided for limited IFR operations in 
Sec. 135.103. Limited IFR can be conducted as a single-pilot operation 
in aircraft with nine or fewer passenger seats. Cargo-only, single-
engine aircraft can operate under IFR or over the top without these 
restrictions.
    Since 1978, the FAA has received 12 petitions for exemptions from 
or amendments to Sec. 135.181 to allow the use of all or specific 
models of single-engine aircraft in passenger-carrying IFR operations. 
The most recent petitions are still pending. Internationally, 
commercial operators in several countries have sought permission to 
conduct passenger operations in IMC with single-engine aircraft. 
Canada, following a cooperative effort with the engine manufacturers, 
aircraft manufacturers, and users that produced a well-documented case, 
has allowed SEIFR passenger-carrying operations in turbine-powered 
airplanes since February 1993, with a number of specific requirements 
for equipment and training. Other countries are also considering 
permitting SEIFR passenger-carrying operations.
    In response to the petitions, the Canadian action, and changes in 
technology that have resulted in increasingly reliable engines and 
aircraft systems, the FAA asked its Office of Integrated Safety 
Analysis to conduct a study to determine if demonstrable differences 
exist between single- and multi-engine aircraft in visual 
meteorological conditions (VMC) and IMC. The study, Part 135 Single-
Engine Instrument Flight Rules Operations in Instrument Meteorological 
Conditions, February 24, 1994, (available in the docket) reviewed the 
basis for the Canadian action and available data from a number of 
sources on powerplant/systems reliability and activity exposure data.
    In September 1994, the FAA asked the Aviation Rulemaking Advisory 
Committee (ARAC) to review the Canadian policy on SEIFR, re-examine FAA 
policies for commercial IMC and night operations by single-engine 
aircraft, determine conditions or limitations that such operations 
should meet, and recommend any changes. The ARAC formed a working group 
that included representatives of the FAA, Transport Canada-Aviation, 
the European Joint Aviation Authority, Australian Civil Aviation, 
several European national aviation authorities, aircraft and engine 
manufacturers, trade associations, pilot unions, and commercial 
operators. The committee recommended that Sec. 135.181 be revised to 
permit SEIFR passenger-carrying operations provided certain 
requirements for equipment and training were met. The ARAC proposal, 
although not technically limited to a particular type of aircraft, 
proposed certain conditions that are met at present only by turbine-
powered aircraft. The ARAC also recommended approval of the Alaska Air 
Carrier Association's (AACA) petition for exemption, which covers both 
turbine-powered and reciprocating engine aircraft. Both the ARAC and 
the FAA study focused on the issue of engine reliability.
    Recently, the National Transportation Safety Board (NTSB) completed 
a study of operations in Alaska Aviation Safety In Alaska, (Safety 
Study NTSB/SS-95/03, PB95-917006). The NTSB noted that unlike the rest 
of the U.S., commuter airline service in Alaska is ``dominated by 
single-engine airplanes powered by a reciprocating engine operating 
under VFR and crewed by one pilot.'' After reviewing Alaska aviation 
accidents from 1988 to 1993 (which include single and multi-engine 
aircraft), the NTSB concluded that ``VFR flight into IMC that results 
in fatal accidents continues to be the most significant safety problem 
in Alaskan aviation.'' VFR flight in IMC in Alaska accounted for 67 
percent (6 of 9) fatal commuter airline accidents and 47 percent (7 of 
15) fatal air taxi accidents. Overall, in Alaska, VFR flight into IMC 
accounted for only 15 percent of the total accidents, but 54 percent of 
the fatal accidents. The NTSB recommended that the FAA proceed with 
rulemaking to allow SEIFR passenger-carrying operations in turbine-
powered aircraft and evaluate whether extending the rule to all single-
engine aircraft would provide a positive effect on safety.
    Prior to the Alaska aviation study, the NTSB conducted a study of 
the emergency medical service (EMS) helicopters because their accident 
rate was twice the rate experienced by part 135 on demand helicopter 
operations and one and half times the rate for all turbine-powered 
helicopters. For the report, ``Safety Study--Commercial Emergency 
Medical Service Helicopter Operations'' (NTSB 1988), an exploration of 
the rapidly growing commercial EMS helicopter industry and its 
operations, the NTSB investigated and evaluated 59 helicopter 
accidents. The Board determined that marginal weather conditions and 
inadvertent flight into IMC remain the most serious hazard that VFR 
helicopters encounter. ``The Board believes that although the IFR 
system is not designed optimally for IFR helicopters and that the 
nature of the EMS helicopter mission further complicates this problem, 
the safety advantages offered by IFR helicopters flown by current and 
proficient pilots are great enough that EMS programs should seriously 
consider obtaining this capability.''
    The Alaska Air Carriers Association in its petition for exemption 
has stated, and the NTSB study confirmed, that in many areas, only 
single-engine aircraft can be operated because of the limitations of 
the landing strips, which severely restrict the availability of air 
transport in these areas. The petitioners further stated that under the 
current rule, unless clear weather is forecast over the entire route 
from 15 minutes from the departure airport to the destination, 
passenger-carrying, single-engine commercial operations are not 
permitted. In many areas, aircraft are the only means of 
transportation; weather forecasts, when available, rarely predict 
continuing VFR conditions. Alaska, they stated, was particularly 
disadvantaged by the current rule. Recent legislation requires the FAA 
to consider the special needs of Alaska when developing its rules.
    As suggested by the NTSB, the FAA reviewed accident data from 1983 
to 1996 on both reciprocating and turbine engines. Data indicated that 
there were 67 accidents in on-demand operations that involved VFR 
flight into IFR

[[Page 64232]]

conditions; single-engine aircraft were involved in 75 percent of these 
accidents. Although the number of such accidents is known, the rate of 
such accidents cannot be determined because the FAA does not collect 
data on the number of flights or flight hours for on-demand operations 
under part 135; therefore, it is not possible to evaluate existing data 
on accidents involving turbine-powered and reciprocating-powered 
single-engine aircraft.

Disposition of Pending Petitions

    The FAA currently has similar petitions for exemptions to 
Sec. 135.181 from the Alaskan Air Carriers Association, Mid-Atlantic 
Freight, Atlantic Aero, Wright Air Service, Inc., Taquan Air Service, 
Inc., and Telford Aviation, Inc. In developing this Notice of Proposed 
Rulemaking, the FAA considered the merits of each of the individual 
petitions and proposed appropriate points and recommendations from 
them. This notice formally disposes of those petitions.

Discussion of the Proposed Rule

    The purpose of this rule is to improve the safety of single-engine, 
passenger-carrying operations by allowing operators to take advantage 
of the IFR system. This proposal would allow planned flight at a 
minimum en route altitude that ensures obstacle clearance and ATC 
communications over a published route, thereby reducing the occurrence 
of continued VFR flight into IMC. Parts 91 and 135 currently require 
additional aircraft equipment, pilot training, experience, and 
qualification, and weather and fuel requirements to operate under IFR. 
Operations under the existing limited IFR rules must meet the 
requirements for IFR operations with the exception that a second pilot 
or autopilot authorization is not needed. The current equipment, pilot, 
weather, fuel, and other differences for VFR and IFR operations are 
outlined in the Table at the end this section. This NPRM proposes to 
remove the limited IFR operations and allow SEIFR operations with 
additional conditions and limitations that will further enhance the 
safety of SEIFR operations over VFR and limited IFR operations.
    The FAA is proposing to change part 135 to allow passenger-carrying 
SEIFR subject to the following conditions:
     A means of engine trend monitoring would be required in 
addition to the inspection requirements of 14 CFR part 91; and
     Two independent electrical power generating sources or, in 
addition to the original electrical power source, a standby battery 
that can maintain 150 percent of the minimum electrical load for at 
least one hour would be required.
    In addition, the limited IFR conditions of current Sec. 135.181 
would be eliminated. The proposed rule changes would not affect cargo-
only operations.
    The FAA originally limited passenger-carrying SEIFR operations 
because of concern about the consequences of engine loss. The February 
1994 FAA study, which focused on the difference between single-engine 
and multi-engine aircraft, found that data that specifically address 
the issue of the reliability of single-engine aircraft in IMC under 
part 135 are necessarily limited to cargo-only operations because 
relatively few passenger-carrying operations occur under these 
conditions. In addition, the FAA does not require manufacturers and 
operators of small aircraft and powerplants to have established 
databases capable of providing information needed to support 
reliability evaluations. Data available collected from various sources 
were found to be frequently incomplete and inconsistent in reporting 
format, limiting their usefulness.
    The 1994 FAA study analysis of NTSB data for part 135 on-demand 
airplane accidents for 1988 to 1990 indicated that although propulsion 
system accidents account for a higher percent of total accidents for 
single-engine (18 percent) than for multi-engine airplanes (6 percent), 
only 2 of the 24 accidents caused by propulsion systems occurred in 
IMC. Accidents involving propulsion system failure in IMC appear to be 
very infrequent occurrences. This can be attributed in part to the 
limits on passenger-carrying operations of aircraft in IMC; however, 
cargo-only IFR operations are included in these data. Weather was a 
casual factor in 24 percent of all accidents; improper flightcrew 
actions contributed to 95 percent of weather-related accidents. 
Mechanical problems, however, were a factor in only one-single-engine 
and one multi-engine weather-related accident, suggesting that 
accidents involving equipment failure during flight in instrument 
conditions are relatively rare events in on-demand air carrier 
operations. The data also show that most accidents in IMC result in 
fatal or serious injuries, regardless of the type of flight plan or 
class of airplane. FAA data on part 135 accidents involving single-
engine aircraft from 1985 to 1992 indicated that the most common causes 
of accidents were weather, poor in-flight planning and decision-making, 
and other weather-related errors resulting from attempts to maintain 
VFR flight.
    Analysis of part 135 scheduled airplane accident data revealed 
patterns in accident causal factors that are very similar to those for 
on demand operations. Analysis of business airplane accidents that 
occurred during part 91 operations provided additional perspective on 
the relative contribution of systems and equipment reliability problems 
to accidents. Accidents involving propulsion and other system failures 
in IMC were infrequent occurrences even though part 91 operators are 
not subject to the same restrictions or level of regulation and 
oversight as part 135 operators.
    The FAA recognizes that engine failure in a single-engine aircraft 
results in an inability to sustain flight. The FAA has determined, 
however, that allowing SEIFR passenger-carrying operations will enhance 
safety over VFR flights in marginal weather conditions and over flights 
under the limited IFR provisions of part 135. Aircraft operating under 
IFR are part of the national IFR system, which includes air traffic 
monitoring and control system; this system ensures that both pilots and 
air traffic controllers know where the aircraft is and can work 
together to avoid hazards and complete the flight safely. Immediate 
emergency assistance is available in the event of an emergency. Data 
from the Rescue Coordination Center have shown that should an accident 
occur, aircraft that were operating under the IFR system are located 
within a few hours; aircraft that were operating under the VFR system 
often take days to locate.
    The FAA does not expect that operators currently flying multi-
engine aircraft will switch to single-engine aircraft simply because of 
this rule change; decisions about the type of aircraft to operate are 
complex. Operators must weigh numerous factors when selecting aircraft, 
including customer base and geographical location. Whatever choice 
operators make, the FAA remains convinced that the proposed rule change 
will increase safety of single-engine, passenger-carrying operations.

New Requirements

    In addition to the inspections requirements of part 43, the FAA is 
proposing to adopt the ARAC suggestion for engine wear and trend 
monitoring. Such monitoring provides an early indication of engine wear 
and increases engine reliability. The engine trend monitoring system 
would require an oil analysis at 100-hour inspection or every

[[Page 64233]]

annual inspection if less than 100 hours have accrued.
    The oil analysis program is an important tool in determining the 
relative state of engine health. Samples of engine oil are collected at 
selected intervals (usually around the 100-hour interval or less) The 
oil samples are identified by make and model of engine, total time on 
the engine, and last oil and filter change. The sample is then sent to 
a laboratory in which the oil is subjected to a series of tests in 
which the amount of trace elements, such as iron and aluminum, are 
identified. A report is sent back to the operator recommending another 
100 hours of operation or, because of an abnormal amount of a 
particular element found in the oil, a particular maintenance action; 
this action may be a simple filter change, or a borescope inspection, 
other maintenance inspection/test, or a complete teardown and rebuild 
of the engine. Regular oil analysis allows the operator to track the 
engine's condition accurately and predict failures before they would 
occur.
    Current IFR requirements require a generator or generators (or 
alternator) able to supply all probable combinations of continuous in-
flight electrical loads for required equipment and for recharging the 
battery. The FAA is also proposing to adopt a modification of the ARAC 
suggestion for two independent electrical power generating sources; the 
proposed rule would specifically allow a standby battery to serve as a 
second power source if the battery can maintain 150 percent of the 
minimum electrical load for at least one hour. This requirement 
introduces redundancy for the generator and alternator and ensures 
that, if a generator or alternator fails, the aircraft will still be 
able to use critical navigation and communication equipment, for a 
period of time in which to effect a safe approach and landing. The FAA 
will consider, and requests comments on other redundant or standby 
electrical systems.
    Section 135.163 (h) currently requires two independent sources of 
energy (with means of selecting either) for powering all gyroscopic 
instruments. Of these sources, at least one must be an engine-driven 
pump or generator; each source must be capable of driving all 
gyroscopic instruments, and installed so that failure of one instrument 
or source does not interfere with the energy supply to the remaining 
instruments or the other energy source, unless, for single-engine 
aircraft, the rate-of-turn indicator has a source of energy separate 
from the bank and pitch and direction indicators.
    The FAA considered requiring electrical or vacuum redundancy to 
drive the gyroscopic instruments, however, the precise configuration of 
that redundancy is not proposed. The FAA is requesting comments on the 
feasibility, benefit, and cost of two independent sources of energy for 
gyroscopic instruments for single engine aircraft. If, for single-
engine aircraft, the rate of turn exception is maintained as stated in 
the current 135.163(h), the FAA will require that training and testing 
on emergency and partial panel operations be provided and evaluated. 
Comments are further requested on whether the rate-of-turn indicator 
powered from a separate source, coupled with required training and 
testing, should be considered adequate for single-engine IFR passenger 
operations.
    Based on the comments received, the FAA may adopt additional 
provisions for a redundant source of power for the gyroscopic 
instruments or electrical systems in the final rule.
    The FAA is proposing to delete the existing limited IFR provisions, 
which allow opeators to take off in IFR conditions if VFR conditions 
are forecast for the remainder of the route from a distance no further 
than 15 minutes flight time for the departure airport. This revision 
eliminates safety deficiencies of the conduct of ``unplanned'' IFR 
flight. Under the limited IFR rule, pilots can only conduct IFR 
operations en route and on an approach if weather conditions were 
unforecast, which means the pilots may not have planned for IFR and may 
have to develop and file a flight plan in flight, while coping with 
unexpected weather conditions. Limited IFR also allows these operations 
to be conducted as a single pilot operation, without a second pilot or 
autopilot that is required for other IFR operations. In addition, the 
limitations on weather forecasting have made this provisions 
impractical in many parts of the U.S.
    It is the FAA's intent that, because multi-engine operators can 
already avail themselves of unrestricted IFR, the proposed removal of 
the limited IFR provision in Sec. 135.181(c) (2) and the exception to 
the second-in-command requirement for limited IFR operations in 
Sec. 135.103 would not impact these operators. The FAA invites comments 
from operators who used the limited IFR provision regarding the 
economic impact of this proposal.
    The proposed changes would allow SEIFR operations in single-engine 
airplanes and turbine-powered helicopters that can be equipped for IFR 
flight. A number of single-engine reciprocating-powered airplanes will 
not be able to upgrade for IFR or would find the cost prohibitive. 
Single-engine, reciprocating-powered helicopters as they currently 
exist are not certificated for IFR operations. Consequently, they would 
not be affected by this rule change.

Other Issues Considered

    The FAA reviewed suggestions made by the ARAC and the petitions 
submitted, but decided against adopting other limitations on SEIFR 
passenger-carrying operations. Some of the ARAC suggestions would have 
limited the rule to turbine-powered aircraft (e.g., use of auto-
ignition/continuous ignition system); the suggested requirement for 
mean time between failure data and simulator training would have 
severely limited the rule, at least in the short-term, to a single 
aircraft, the Cessna Caravan. The FAA does not believe that such a 
limitation is justified because flying IFR improves the safety of all 
operations over flying VFR in marginal weather conditions and flight 
under the current limited IFR provisions.
    A number of suggested requirements were not adopted because they 
are already covered under existing rules; for example, autopilot 
training and proficiency checks are currently required. The FAA decided 
that the suggested requirement for an air transport pilot certificate 
for commuter operations was unnecessary because of size and complexity 
of single-engine aircraft. Current requirements for single-engine, IFR 
provide for at least a commercial certificate with appropriate category 
and class ratings, and if required, type ratings, 1,200 hours of flight 
time including 500 hours of cross country, 100 hours of night, and at 
least 50 hours of actual instrument flight time. Other ARAC suggestions 
were not proposed because they go beyond what is required for aircraft 
certification (e.g., manual throttles and auto ignition); the FAA 
decided that it was inappropriate to alter certification rules through 
this rulemaking. The ARAC proposal for IFR-approved area navigation 
equipment that provides immediate identification of and heading to the 
nearest airport was not proposed in this NPRM. The safety benefit of 
this equipment has not been established. Finally, the FAA has not 
proposed the ARAC and other petitioners' suggestion for a radar 
altimeter. Such altimeters are only required for Category II and III 
operations; the FAA believes that the benefits of such altimeters for 
other operations have not been established to a sufficient degree to 
justify the considerable costs.

[[Page 64234]]

    Canada adopted a limitation on flights in mountainous areas in its 
SEIFR rule; the AACA in its petition proposed a limitation for 
mountainous areas as defined by Sec. 95.17. The Atlantic Aero, Inc. and 
Mid-Atlantic Freight Inc. 1994 petition for exemption proposed to limit 
SEIFR operations to routes where the minimum en route altitude (MEA) 
was no greater than 10,000 feet mean sea level (MSL). Taquan Air 
proposed to limit SEIFR operations to routes where the MEA was no 
greater than 12,000 feet MSL. The FAA decided that a mountainous 
terrain restriction was not needed. The definition of mountainous 
terrain in part 95 is very broad and would limit flight unnecessarily. 
Under part 95, almost all of Alaska, Hawaii, and the western third of 
the country are classified as mountainous. Single-engine cargo IFR 
operations and limited IFR operations are not similarly restricted. The 
FAA notes that some single-engine airplanes are limited by their 
service ceilings; others are limited by the lack of pressurization or 
oxygen. In some areas, the lack of navigational equipment also will 
limit flight over mountainous terrain. The FAA further notes that some 
pressurized single-engine aircraft can cruise at altitudes that provide 
much more time for making a safe landing should the engine fail. 
Finally, the difficulties of finding a safe landing area for all 
aircraft are not unique to mountainous terrain; densely populated areas 
may pose similar problems.

Section-by-Section Discussion of Proposed Changes

    Section 135.83 would be amended to change the reference to 
Sec. 135.181 to make it consistent with the revised rule.
    Section 135.101 would be revised to eliminate the reference to 
Sec. 135.103, which would be deleted, and to delete the work 
``conditions'' after IFR. Deletion of the word ``conditions'' clarifies 
that any operation for which an IFR flight plan is filed must have a 
second pilot or an autopilot, even if the flight can be conducted in 
VFR conditions.
    Section 135.103 would be deleted because it is no longer needed.
    Section 135.163 would be revised to add, for single-engine aircraft 
reference to alternators as well as the proposed requirement for two 
independent electrical power generating sources or a standby battery.
    Section 135.181 would be revised by dropping all of the limited IFR 
conditions. Only the performance requirements for multi-engine aircraft 
would remain.
    Section 135.421 would be revised to add the requirement for engine 
trend monitoring for aircraft used in passenger-carrying SEIFR 
operations.

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Regulatory Evaluation Summary

    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 effect of regulatory changes on international trade. In conducting 
these analyses, the FAA has determined that this rule: (1) Would 
generate benefits that justify its costs and is not ``significant 
regulatory action'' as defined in the Executive Order; (2) is not 
significant as defined in Department of Transportation Regulatory 
Policies and procedures; and (3) would not constitute a barrier to 
international trade. These analyses, available in the docket, are 
summarized below.

Cost-Benefit Analysis

    The FAA proposes to update and revise the regulations to allow 
single-engine, passenger carrying aircraft to operate under the safer 
instrument flight rules. This proposal would require additional 
conditions and requirements that will further enhance the safety of 
single engine instrument flight rules (SEIFR) operations.
    The cost of this proposed rule is estimated at $33.9 million ($27.5 
million, discounted). The most costly provision is on the requirement 
for an autopilot, which is estimated at $25.6 million ($20.9 million 
discounted) and represents about 76 percent of the total. The FAA 
concludes that the expected quantitative benefits would be a minimum of 
$185.0 million or $129.9 million discounted. This action would increase 
the safety of single-engine passenger-carrying operations because it 
would allow them to operate under instrument flight rules. The proposal 
would reduce the incentive for operators to conduct low altitude 
operations under marginal weather conditions in order to not lose 
business. It would require operators to meet the more stringent 
requirements for such flights including additional aircraft equipment.

Initial Regulatory Flexibility Assessment

    The Regulatory Flexibility Act of 1980 (RFA) was enacted by 
Congress to ensure that small entities are not unnecessarily or 
disproportionately burdened by Federal Regulations. The RFA requires an 
analysis if a proposed rule would have ``a significant economic impact 
on a substantial number of small entities.'' The definitions of small 
entities and guidance material for making determinations required by 
the RFA are contained in the Federal Register (47 FR 32825, July 29, 
1982). Federal Aviation Administration (FAA) order 2100.14A outlines 
the agency's procedures and criteria for implementing the RFA.
    With respect to the propose rule, a ``small entity'' is an operator 
of aircraft for hire with nine or fewer aircraft. A ``significant 
economic impact on a small entity'' is defined as an annualized net 
compliance cost for operators of aircraft for hire which in 1996 
dollars is $125,100 for scheduled operators whose aircraft have more 
than 60 seats. It is $69,900 for scheduled operators whose fleets have 
aircraft with seating capacities of 60 or fewer seats (other scheduled 
operators) and $4,900 for unscheduled operators. A substantial number 
of small entities is defined as a number that is 11 or more and which 
is more than one-third of small operators subject to the proposed rule:
    The analysis shows that the annualized cost of the proposed rule 
(assuming no cost savings) is about $1,400 per aircraft and the 
annualized safety and non-safety benefits is about $2,050 per aircraft. 
Therefore, the annualized net savings is about $650 per aircraft.
    The FAA has determined that operators with eight aircraft or more 
would incur a significant positive impact. However, fewer than one-
third of the entities would incur a significant positive cost impact. 
Therefore, the FAA has determined that a substantial number of 
operators would not be positively or negatively impacted in a 
significant way.

International Trade Impact Statement

    This proposed rule is not expected to have any impact on trade 
opportunities for U.S. firms doing business overseas or foreign firms 
doing business in the United States. The proposed rule would primarily 
affect U.S. operators of aircraft for hire that provide domestic 
service.

Unfunded Mandates Reform Act Assessment

    Title II of the Unfunded Mandates Reform Act of 1995 (the Act), 
enacted as Pub. L. 104-4 on March 22, 1995, requires each Federal 
agency, to the extent permitted by law, to prepare a written assessment 
of the effects of any Federal mandate in a proposed or final agency 
rule that may result in the expenditure by State, local, and tribal 
governments, in the aggregate, or by the private sector, of $100 
million or more (adjusted annually for inflation) in any one year. 
Section 204(a) of the Act, 2 U.S.C. 1534(a), require the Federal agency 
to develop an effective process to permit timely input by elected 
officers (or their designees) of State, local, and tribal governments 
on a proposed ``significant intergovernmental mandate.'' A 
``significant intergovernmental mandate'' under the Act is any 
provision in a Federal agency regulation that would impose an 
enforceable duty upon State, local, and tribal governments, in the 
aggregate, of $100 million (adjusted annually for inflation) in any one 
year. Section 203 of the Act, 2 U.S.C. 1533, which supplements section 
204(a), provides that before establishing any regulatory requirements 
that might significantly or uniquely affect small governments, the 
agency shall have developed a plan that, among other things, provides 
for notice to potentially affected small governments, if any, and for a 
meaningful and timely opportunity to provide input in the development 
of regulatory proposals.
    This proposal rule does not meet the cost thresholds described 
above. Furthermore, this proposed rule would not impose a significant 
cost on small governments and would not uniquely affect those small 
governments. Therefore, the requirements of Title II of the Unfunded 
Mandates Reform Act of 1995 do not apply.

Paperwork Reduction Act

    This proposed rule contains not information collection requests 
requiring approval of the Office of Management and Budget pursuant to 
the Paperwork Reduction Act (44 U.S.C. 3507 et seq.).

International Civil Aviation Organization and Joint Aviation 
Regulations

    In keeping with U.S. obligations under the Convention on 
International Civil Aviation, it is FAA policy to comply with 
International Civil Aviation Organization Standards and Recommended 
Practices to the maximum extent practicable. The FAA has determined 
that this proposal, if adopted, would not present any major 
differences.

Federalism Implications

    The changes proposed by this NPRM would not have a substantial 
direct effect on the States, on the relationship between the National 
Government and

[[Page 64240]]

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 the proposed amendments 
would not have federalism implications requiring the preparation of a 
Federalism Assessment.

Conclusion

    For the reasons discussed in the preamble, and based on the 
findings in the Initial Regulatory Flexibility Determination and the 
International Trade Impact Analysis, 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 on a substantial number of small 
entities under the criteria of the Regulatory Flexibility Act. This 
proposal is not considered significant under DOT Order 2100.5, Policies 
and Procedures for Simplification, Analysis, and Review of Regulations.

List of Subjects in 14 CFR Part 135

    Air taxis, Aircraft, Aviation safety, Safety, Single-engine 
aircraft.
    For the reasons set out in the preamble, 14 CFR part 135 is 
proposed to be amended as set forth below:

PART 135--AIR TAXI OPERATORS AND COMMERCIAL OPERATORS

    1. The authority citation for part 135 continues to read as 
follows:

    Authority: 49 USC 106(g), 40113, 44701-44702, 44705, 44709, 
44711-44713, 44715-44717, 44722.

    2. Section 135.101 is revised to read as follows:


Sec. 135.101  Second in command required under IFR.

    Except as provided in Sec. 135.105, no person may operate an 
aircraft carrying passengers under IFR unless there is a second in 
command in the aircraft.
    3. Section 135.103 is removed and reserved.
    4. Section 135.163 is amended to revise paragraphs (f) and (g) to 
read as follows:


Sec. 135.163  Equipment requirements: Aircraft carrying passengers 
under IFR.

* * * * *
    (f) For a single-engine aircraft:
    (1) two independent electrical power generating sources each of 
which is able to supply all probable combinations of continuous 
inflight electrical loads for required instruments and equipment; or
    (2) in addition to single electrical power generating source, a 
standby battery that is capable of providing 150 percent of the minimum 
electrical load for at least one hour to operate navigation and 
communication equipment.
    (g) For multi-engine aircraft, at least two generators or 
alternators each of which is on a separate engine, of which any 
combination of one-half of the total number are rated sufficiently to 
supply the electrical loads of all required instruments and equipment 
necessary for safe emergency operation of the aircraft except that for 
multi-engine helicopters, the two required generators may be mounted on 
the main rotor drive train; and
* * * * *
    5. Section 135.181 is amended to revise paragraph (a)(1) and (c) to 
read as follows:


Sec. 135.181  Performance requirements: Multi-engine aircraft operated 
over-the-top or in IFR conditions.

    (a) * * *
    (1) Operate a single-engine aircraft carrying passengers over-the-
top; or
* * * * *
    (c) Without regard to paragraph (a) of this section, if the latest 
weather reports or forecasts, or any combination of them, indicate that 
the weather along the planned route (including takeoff and landing) 
allows flight under VFR under the ceiling (if a ceiling exists) and 
that the weather is forecast to remain so until at least 1 hour after 
the estimated time of arrival at the destination, a person may operate 
an aircraft over-the-top.
 * * * * *
    6. Section 135.421 is amended to add paragraph (c) to read as 
follows:


Sec. 135.421  Additional maintenance requirements.

* * * * *
    (c) For each single engine aircraft to be used in passenger-
carrying IFR operations, each certificate holder must incorporate into 
the manufacturer's recommended maintenance program or FAA approved 
maintenance program, an engine trend monitoring program including an 
oil analysis at each 100 hour interval and a record of the findings.

    Issued in Washington, DC. on November 21, 1996.
Thomas C. Accardi,
Director, Flight Standards Service.
[FR Doc. 96-30365 Filed 12-2-96; 8:45 am]
BILLING CODE 4910-13-M