[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
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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
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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
