[Federal Register Volume 64, Number 57 (Thursday, March 25, 1999)]
[Proposed Rules]
[Pages 14408-14410]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-7319]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM152; Notice No. 25-99-01-SC]


Special Conditions: Boeing Model 717-200 Airplane; Operation 
Without Normal Electrical Power

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This notice proposes special conditions for the Boeing Model 
717-200 airplane. This airplane will have novel or unusual design 
features associated with its electronic flight and engine control 
systems. The applicable airworthiness regulations do not contain 
adequate or appropriate safety standards for these design features. 
These proposed special conditions contain the additional safety 
standards that the Administrator considers necessary to establish a 
level of safety equivalent to that established by the existing 
airworthiness standards.

DATES: Comments must be received on or before April 26, 1999.

ADDRESSES: Comments on this proposal may be mailed in duplicate to: 
Federal

[[Page 14409]]

Aviation Administration, Office of the Assistant Chief Counsel, 
Attention: Rules Docket (ANM-7), Docket No. NM152, 1601 Lind Avenue SW, 
Renton, Washington 98055-4056, or delivered in duplicate to the Office 
of the Assistant Chief Counsel at the above address. Comments must be 
marked: NM152. Comments may be inspected in the Rules Docket weekdays, 
except Federal holidays, between 7:30 a.m. and 4:00 p.m.

FOR FURTHER INFORMATION CONTACT: Gerry Lakin, FAA, Standardization 
Branch, ANM-113, Transport Standards Staff, Transport Airplane 
Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., 
Renton, Washington 98055-4056; telephone (425) 227-1187, facsimile 
(425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of 
these proposed special conditions by submitting such written data, 
views, or arguments as they may desire. Communications should identify 
the regulatory docket or notice number and be submitted in duplicate to 
the address specified above. All communications received on or before 
the closing date for comments will be considered by the Administrator. 
The proposals described in this notice may be changed in light of the 
comments received. All comments received will be available in the Rules 
Docket for examination by interested persons, both before and after the 
closing date for comments. A report summarizing each substantive public 
contact with FAA personnel concerning this rulemaking will be filed in 
the docket. Persons wishing the FAA to acknowledge receipt of their 
comments submitted in response to this notice must include with those 
comments a self-addressed, stamped postcard on which the following 
statement is made: ``Comments to Docket No. NM152.'' The postcard will 
be date stamped and returned to the commenter.

Background

    On August 8, 1994, the Los Angeles Certification Office received an 
application from the McDonnell Douglas Corporation, now a wholly owned 
subsidiary of The Boeing Company, informing the FAA of their intention 
to seek an amendment to FAA Type Certificate No. A6WE to add the new 
Model MD-95-30, which was later renamed the Boeing Model 717-200.
    The Boeing Model 717-200 is a derivative of the DC-9/MD-80/MD-90 
series of airplanes, Type Certificate No. A6WE, and is scheduled to be 
certificated in July 1999. The Boeing Model 717-200 is a low-wing, 
pressurized airplane with twin, body-mounted, jet engines that is 
configured for approximately 100 passengers. The airplane has a maximum 
takeoff weight of 121,000 pounds, a maximum landing weight of 104,000 
pounds, a maximum operating altitude of 37,000 feet, and a range of 
1500 nautical miles at a cruise speed of Mach 0.76. The overall length 
of the Boeing Model 717-200 is 124 feet, the height is 29 feet, 1 inch, 
and the wing span is 93 feet, 4 inches. Features have been added to the 
Boeing Model 717-200 to provide cost-efficient performance and 
decreased crew workload. These features include an advanced flight 
compartment, BMW/Rolls-Royce BR715 engines, an advanced auxiliary power 
unit (APU), advanced environmental systems, and an updated interior.
    The advanced flight compartment includes an electronic instrument 
system, with six liquid crystal displays, to show navigation, engine, 
and system data. For decreased crew workload, the Boeing Model 717-200 
has a flight management system and an autoflight system, with Category 
IIIa autoland capability. A central fault display system allows 
maintenance personnel access to fault data to perform return-to-service 
tests.
    The Boeing Model 717-200 is equipped with two electronically 
controlled BMW/Rolls-Royce BR715 high-bypasss ratio engines capable of 
supplying up to 21,000 pounds of thrust. For reverse thrust, the engine 
has fixed pivot door type thrust reversers.
    The advanced APU is a simple design with a single-stage compressor 
and turbine. The APU uses modular components for increased reliability 
and decreased maintenance and is controlled by an electronic control 
unit.
    The Boeing Model 717-200 has a simplified pneumatic system to 
supply bleed-air for the airplane systems. The dual cabin pressure 
control system has automatic control, with a manual backup.
    The passenger compartment interior has overhead stowage 
compartments, forward and aft lavatories, and two forward service 
galleys. The interior also has a full-grip lighted handrail attached to 
the overhead stowage compartments, for safety and convenience. Class C 
cargo compartments are located in the lower forward and aft ends of the 
airplane.

Type Certification Basis

    Under the provisions of Sec. 21.101, The Boeing Company must show 
that the Boeing Model 717-200 meets the applicable provisions of the 
regulations incorporated by reference in Type Certificate No. A6WE or 
the applicable regulations in effect on the date of application for the 
change to the type certificate. The regulations incorporated by 
reference in the type certificate are commonly referred to as the 
``original type certification basis.'' The regulations incorporated by 
reference in Type Certificate No. A6WE are as follows:
    The type certification basis for the Boeing Model 717-200 airplane 
is 14 CFR part 25, effective February 1, 1965, as amended by Amendments 
25-1 through 25-82, except for certain reversions to earlier amendments 
for parts of the airplane not affected by these special conditions.
    In addition, the certification basis for the Boeing Model 717-200 
includes the fuel vent and exhaust emission requirements of 14 CFR part 
34, effective September 10, 1990, plus any amendments in effect at the 
time of certification; and the noise certification requirements of 14 
CFR part 36, effective December 1, 1969, as amended by Amendment 36-1 
through the amendment in effect at the time of certification. These 
special conditions will form an additional part of the type 
certification basis. The certification basis may also include other 
special conditions and exemptions that are not relevant to these 
special conditions.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., part 25 as amended) do not contain adequate or 
appropriate safety standards for the Boeing Model 717-200 because of a 
novel or unusual design feature, special conditions are prescribed 
under the provisions of Sec. 21.16.
    Special conditions, as appropriate, are issued in accordance with 
Sec. 11.49 after public notice, as required by Secs. 11.28 and 
11.29(b), and become part of the type certification basis in accordance 
with Sec. 21.101(b)(2).
    Special conditions are initially applicable to the model for which 
they are issued. Should the type certificate for that model be amended 
later to include any other model that incorporates the same novel or 
unusual design feature, or should any other model already included on 
the same type certificate be modified to incorporate the same novel or 
unusual design feature, the special conditions would also apply to the 
other model under the provisions of Sec. 21.101(a)(1).

Novel or Unusual Design Features

    The Boeing Model 717-200 will utilize electronic flight and engine 
control systems that establish the

[[Page 14410]]

criticality of the electrical power generation and distribution 
systems. Since the loss of all electrical power may be catastrophic to 
the airplane, a special condition is proposed to retain the level of 
safety envisioned by Sec. 25.1351(d).
    The Boeing Model 717-200 airplane requires a continuous source of 
electrical power in order for the electronic flight instrument system 
to remain operable. Section Sec. 25.1351(d), ``Operation without normal 
electrical power,'' requires safe operation in visual flight rule (VFR) 
conditions for a period of not less than five minutes with inoperative 
normal power. This rule was structured around a traditional design 
utilizing analog/mechanical flight instrumentation, which allows the 
crew to sort out the electrical failure, start engine(s) if necessary, 
and re-establish some of the electrical power generation capability. 
However, with today's aircraft, complex electronic/avionics systems are 
now performing critical functions that may require uninterrupted 
electrical power for continued safe flight (in instrument 
meteorological conditions (IMC)) and landing.
    In addition, Sec. 121.161 states that an operator may fly a twin-
engine airplane over a route that allows up to one hour flying time 
from a suitable airport. If Boeing seeks operational approval for 
extended over water operations, with a possible diversion time of one 
hour, the emergency power system must be capable of providing at least 
one hour of operation to critical and essential systems. If, however, 
Boeing intends to exclude extended over water operations, then only 30 
minutes of emergency power will be required.
    In order to maintain the same level of safety associated with 
traditional designs, the Boeing Model 717-200 design must provide at 
least 30 minutes of emergency power without the normal source of engine 
or APU generated electrical power. It should be noted that service 
experience has shown that the loss of all electrical power generated by 
the airplane's engine generators or APU is not extremely improbable. 
Thus, it must be demonstrated that the airplane can continue through 
safe flight and landing with only the use of its emergency electrical 
power systems. These emergency electrical power systems must be able to 
power loads that are essential for continued safe flight and landing. 
The emergency electrical power system must be designed to:
    1. Continue to operate the airplane for immediate safety without 
the need for crew action following the loss of the normal engine (which 
includes APU power) generator electrical power system,
    2. Supply electrical power required for continued safe flight and 
landing, and
    3. Supply electrical power required to restart the engines.
For compliance purposes a test demonstration of the loss of normal 
engine generator power is to be established such that:
    1. The failure condition is assumed to occur during night IMC at 
the most critical phase of the flight relative to the electrical power 
system design and distribution of equipment loads on the system.
    2. The airplane engine restart capability must be provided and 
operations continued in IMC after the unrestorable loss of normal 
engine generator power.
    3. The airplane is demonstrated to be capable of continuous safe 
flight and landing. The length of time must be computed based on the 
maximum diversion time capability for which the airplane is being 
certified. Consideration for speed reductions resulting from the 
associated failure must be made.
    4. The availability of APU operation should not be considered in 
establishing emergency power system adequacy.

Applicability

    As discussed above, these special conditions are applicable to the 
Boeing Model 717-200. Should The Boeing Company apply at a later date 
for a change to the type certificate to include another model 
incorporating the same novel or unusual design feature, the special 
conditions would apply to that model as well under the provisions of 
Sec. 21.101(a)(1).

Conclusion

    This action affects only certain novel or unusual design features 
on Boeing Model 717-200 airplanes. It is not a rule of general 
applicability, and it affects only the applicant who applied to the FAA 
for approval of these features on the airplane.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

    The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.

The Proposed Special Conditions

    Accordingly, the Federal Aviation Administration (FAA) proposes the 
following special conditions as part of the type certification basis 
for Boeing Model 717-200 airplanes.
    1. Operation Without Normal Electrical Power. In lieu of compliance 
with Sec. 25.1351(d), ``It must be demonstrated by test, or combination 
of test and analysis, that the airplane can continue safe flight and 
landing with inoperative normal engine and APU generator electrical 
power (electrical power sources excluding the battery and any other 
standby electrical sources). The airplane operation must be considered 
at the critical phase of flight and include the ability to restart the 
engines and maintain flight for the maximum diversion time capability 
being certified.''

    Issued in Renton, Washington on March 17, 1999.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service, ANM-100.
[FR Doc. 99-7319 Filed 3-24-99; 8:45 am]
BILLING CODE 4910-13-P