[Federal Register Volume 59, Number 5 (Friday, January 7, 1994)]
[Proposed Rules]
[Pages 984-986]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-363]


[[Page Unknown]]

[Federal Register: January 7, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 33

[Docket No. 93-ANE-65; Notice No. 33-ANE-04]

 

Special Conditions; Rolls-Royce Model(s) RB211-Trent-875-17/-877-
17/-884-17 Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This notice proposes special conditions for the Rolls-Royce 
Model(s) RB211-Trent-875-17, -877-17, and -884-17 turbofan engines. The 
applicable regulations do not contain adequate or appropriate safety 
standards for the protection of these systems from medium and large 
bird ingestion. This notice proposes the additional safety standards 
which the Administrator considers necessary to establish a level of 
safety equivalent to that established by the airworthiness standards of 
Part 33 of the Federal Aviation Regulations (FAR).

DATES: Comments must be submitted on or before February 22, 1994.

ADDRESSES: Comments on this proposal may be submitted in triplicate to: 
Federal Aviation Administration (FAA), New England Region, Office of 
the Assistant Chief Counsel, Attn: Rules Docket No. 93-ANE-65, 12 New 
England Executive Park, Burlington, Massachusetts 01803-5299. Comments 
must be marked: Docket No. 93-ANE-65. Comments may be inspected at this 
location between 8 a.m. and 4:30 p.m., Monday through Friday, except 
Federal holidays.

FOR FURTHER INFORMATION CONTACT:
John Golinski, Engine and Propeller Standards Staff, ANE-110, Engine 
and Propeller Directorate, Aircraft Certification Service, FAA, New 
England Region, 12 New England Executive Park, Burlington, 
Massachusetts 01803-5229; telephone (617) 238-7119; fax (617) 238-7199.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed special conditions by submitting such written data, views, or 
arguments as they may desire. Communications should identify the Rules 
Docket number and be submitted in triplicate to the address specified 
under ADDRESSES. All communications received on or before the closing 
date for comments, specified under DATES, will be considered by the 
Administrator before taking action on the proposal. The proposal 
contained in this notice may be changed in light of the comments 
received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed special 
conditions. All comments submitted 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 proposal will be filed in 
the docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit with those comments a 
self-addressed, stamped postcard on which the following statement is 
made: ``Comments to Docket No. 93-ANE-65.'' The postcard will be date 
stamped and returned to the commenter.

Background

    On August 4, 1992, Rolls-Royce applied for type certification of 
Rolls-Royce Model(s) RB211-Trent-870-17, -877-17, and -884-17 turbofan 
engines. The application for type certification of the Model RB211-
Trent-870-17 turbofan engine was withdrawn and a new application for 
type certification of the Model RB211-Trent-875-17 was made on April 6, 
1993. The FAA has determined that the current foreign object ingestion 
requirements of Sec. 33.77(a) for four pound birds; and Sec. 33.77(b) 
for one and one-half pound flocking birds, do not adequately represent 
the bird threat encountered in service. A study of in-service bird 
ingestion events has indicated a need to modify the bird ingestion 
requirements of this section to ensure design integrity and demonstrate 
an adequate level of safety.
    The FAA has concluded that additional safety standards must be 
applied to Rolls-Royce Model(s) RB211-Trent-875-17, -877-17, and -844-
17 turbofan engines to demonstrate that they are capable of acceptable 
operation after medium and large bird ingestion. The applicable 
airworthiness requirements do not contain adequate or appropriate 
safety standards for type certification with respect to the new design 
criteria. This new design criteria assumes the actual bird threat 
encountered in service.

Type Certification Basis

    Under the provisions of Sec. 21.101 of the FAR, Rolls-Royce must 
show that the Rolls-Royce Model(s) RB211-Trent-875-17, -877-17, and -
884-17 turbofan engines meet the requirements of the applicable 
regulations in effect on the date of the application. Those Federal 
Aviation Regulations are Sec. 21.21 and Part 33, effective February 1, 
1965, as amended through August 10, 1990, Amendment 33-14.
    The Administrator finds that the applicable airworthiness 
regulations in part 33, as amended, do not contain adequate or 
appropriate safety standards for the Rolls-Royce Model(s) RB211-Trent-
800 series turbofan engine because of its unique design criteria. 
Therefore, the Administrator proposes these special conditions under 
the provisions of Sec. 21.16 to establish a level of safety equivalent 
to that established in the regulations.
    Special conditions, as appropriate, are issued in accordance with 
Sec. 11.49 of the FAR after public notice and opportunity for comment, 
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).

Conclusion

    This action affects only Rolls-Royce Model(s) RB211-Trent-875-17, -
877-17, and -884-17 turbofan engines. It is not a rule of general 
applicability and affects only the manufacturer who applied to the FAA 
for approval of these new design criteria on the engine.

List of Subjects in 14 CFR Part 33

    Air transportation, Aircraft, Aviation safety, Safety.

    The authority citation for these special conditions continues to 
read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421, 1423; 49 U.S.C. 106(g); 
14 CFR 21.16, and 14 CFR 11.28.

The Proposed Special Conditions

    Accordingly, the Federal Aviation Administration (FAA) proposes the 
following special conditions as part of the type certification basis 
for the Rolls-Royce Model(s) RB211-Trent-875-17, -877-17, and -884-17 
turbofan engines.
    In lieu of the requirements of FAR Sec. 33.77(a) and (b), the 
following tests and analyses must be conducted, unless compliance can 
be shown by alternate methods acceptable to the Administrator:
    (a) It must be shown that the ingestion of a single large bird, 
under the conditions prescribed in Appendix A, will not cause the 
engine to:
    (1) catch fire;
    (2) release hazardous fragments through the engine casing;
    (3) generate loads greater than those ultimate loads specified 
under Sec. 33.23(a);
    (4) lose the ability to be shut down; or
    (5) generate other conditions hazardous to the aircraft.
    (b) Alternatively, if compliance with the bird ingestion 
requirements of paragraph (a) of this special condition is not 
established, the applicant must demonstrate that compliance with the 
containment requirements of Sec. 33.94(a) constitutes a more severe 
demonstration than the requirements of paragraph (a) of this special 
condition. The engine type certification documentation will then be 
endorsed to reflect this alternative compliance method.

Appendix A--Large Bird Ingestion Test Procedures

    (a) The test shall be conducted with the engine stabilized at 
rated takeoff thrust for the test day ambient conditions prior to 
the ingestion.
    (b) The test shall be conducted using one eight-pound bird 
targeted at the most critical location and ingested at a bird speed 
of 200 knots.
    (c) Power lever movement is not permitted within 15 seconds 
following the ingestion event.

End of Appendix A


    (c) It must be shown that the ingestion of medium birds, under the 
conditions prescribed in Appendix B, will not cause the engine to:
    (1) Sustain more than a 25 percent thrust loss;
    (2) Be shut down during the required run-on demonstration 
prescribed in Appendix B;
    (3) Exceed any engine operating limitations to the extent that the 
engine cannot comply with this section; or
    (4) Generate other conditions hazardous to the aircraft. 
Appendix B--Medium Bird Ingestion Test Procedures 
    (a) The ingestion test shall be conducted with the engine 
stabilized at rated takeoff thrust for the test day ambient 
conditions prior to the ingestion.
    (b) The test shall be conducted to simulate a flock encounter, 
with all birds ingested within approximately one second, and using 
the more severe of the following bird weight/quantity combinations:
    (1) Six 1.5-pound and one 2.5-pound birds.
    (2) Four 2.5-pound birds.
    (c) Bird targeting shall be one 2.5-pound bird at the core 
primary flow path, and the remaining birds targeted at critical fan 
rotor locations.
    (d) Bird ingestion velocity shall be the most critical velocity 
between V1 minimum through 250 knots.
    (e) Power lever movements between stages must occur in 10 
seconds or less. The following test schedule will be used as the 
post-ingestion run-on demonstration:
    (1) Two minutes with no power lever movement.
    (2) Three minutes at 75 percent of takeoff thrust.
    (3) Six minutes at 75 percent of maximum continuous thrust.
    (4) Six minutes at 50 percent of maximum continuous thrust.
    (5) One minute at approach idle.
    (6) Two minutes at 75 percent of takeoff thrust.
    (7) Retard throttle to idle.
    (8) Shut down the engine.
    (f) An analysis or component/engine test(s) acceptable to the 
Administrator shall be conducted to determine the critical ingestion 
parameters for medium bird ingestion that relates to airspeeds from 
V1 minimum through 250 knots. The analysis or test(s) must also show 
satisfactory engine operation for medium bird ingestion at the most 
severe ambient operating condition approved for the engine that may 
be experienced in service.

End of Appendix B

    (d) It must be shown that engine spinner impact by one large bird 
and by the single largest medium bird, under the respective conditions 
prescribed in Appendices A and B, will not affect the engine to the 
extent that it cannot comply with the requirements of paragraphs (a) 
and (b) of this special condition.

    Issued in Burlington, Massachusetts, on December 29, 1993.
Jay J. Pardee,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 94-363 Filed 1-6-94; 8:45 am]
BILLING CODE 4910-13-M