[Federal Register Volume 59, Number 144 (Thursday, July 28, 1994)]
[Unknown Section]
[Page ]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-18362]


[Federal Register: July 28, 1994]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-ANE-17]


Airworthiness Directives; AlliedSignal Aerospace GTCP85 Series 
Auxiliary Power Units

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to AlliedSignal Aerospace (formerly 
Garrett Auxiliary Power Division and Garrett Turbine Engine Co.) GTCP85 
series auxiliary power units (APU). This proposal would require 
modifying the APU to install an exhaust centerbody. This proposal is 
prompted by reports of two uncontained APU failures where turbine wheel 
fragments exited the APU exhaust axially and damaged the aircraft. The 
actions specified by the proposed AD are intended to prevent an axially 
uncontained APU failure and damage to the aircraft.

DATES: Comments must be received by September 26, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 94-ANE-17, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location between 8:00 a.m. and 4:30 p.m., Monday through Friday, 
except Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from AlliedSignal Aerospace Services, P.O. Box 52170, Phoenix, 
AZ 85072-2170, Attn. Dept. 65-71, Mailstop 1802-AA. This information 
may be examined at the FAA, New England Region, Office of the Assistant 
Chief Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Robert Baitoo, Aerospace Engineer, Los 
Angeles Aircraft Certification Office, FAA, Transport Airplane 
Directorate, 3229 E. Spring St., Long Beach, CA 90806-2425; telephone 
(310) 988-5245, fax (310) 988-5210.

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. Communications should identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals 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 rule. All 
comments submitted 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 Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 94-ANE-17.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Assistant Chief Counsel, 
Attention: Rules Docket No. 94-ANE-17, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    Federal Aviation Administration (FAA) has received reports of two 
incidents where AlliedSignal Aerospace (formerly Garrett Auxiliary 
Power Division and Garrett Turbine Engine Co.) GTCP85 series auxiliary 
power units (APU) experienced uncontained failures. In both incidents, 
the APU turbine wheel fragments exited the APU exhaust axially and 
damaged the aircraft while on the ground. The FAA has determined that 
this failure mode is a potential safety hazard both on the ground and 
in flight, as the APU can release turbine wheel fragments that can 
penetrate the aircraft APU exhaust duct and cause damage to other 
aircraft systems. In addition, the hot turbine wheel fragments can pose 
a fire hazard. This condition, if not corrected, could result in an 
axially uncontained APU failure and damage to the aircraft.
    FAA has reviewed and approved the technical contents of 
AlliedSignal Aerospace Service Bulletin (SB) No. GTCP85-49-A6831, dated 
March 17, 1994, applicable to APU's installed on McDonnell Douglas DC-
9/MD-80 series aircraft, and SB No. GTCP85-49-6919, dated May 17, 1994, 
applicable to APU's installed on several other aircraft makes and 
models. These SB's describe procedures for modifying the APU to install 
an exhaust centerbody.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require modifying the APU to install an exhaust 
centerbody to contain turbine wheel fragments from exiting the APU 
axially. Due to the increased risk associated with airborne failures, 
flight operable APU's would be required to be modified within 24 months 
after the effective date of the AD, and within 36 months after the 
effective date of this AD for APU's that are ground operable only. The 
actions would be required to be accomplished in accordance with the 
service bulletins described previously.
    There are approximately 3,000 APU's of the affected design in the 
worldwide fleet. The FAA estimates that 1,500 APU's installed on 
aircraft of U.S. registry would be affected by this proposed AD, that 
it would take approximately 5 work hours per APU to accomplish the 
proposed actions, and that the average labor rate is $55 per work hour. 
Required parts would cost approximately $7,055 per APU if the exhaust 
duct is not reworkable, $3,254 per APU if the exhaust duct is 
reworkable, and the FAA estimates that 1,050 domestic APU's are 
reworkable. Based on these figures, the total cost impact of the 
proposed AD on U.S. operators is estimated to be $7,003,950.
    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.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety. The Proposed 
Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (14 CFR part 39) as 
follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [AMENDED]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

AlliedSignal Aerospace: Docket No. 94-ANE-17.

    Applicability: AlliedSignal Aerospace (formerly Garrett 
Auxiliary Power Division and Garrett Turbine Engine Co.) GTCP85 
series auxiliary power units (APU's) installed on but not limited to 
British Aerospace BAC 1-11 series aircraft; Boeing 707 series 
aircraft, 727 series aircraft, 737 series aircraft; Lockheed L382 
series aircraft; McDonnell Douglas DC-8-70 series aircraft, and DC-
9/MD-80 series aircraft.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent an uncontained APU failure and damage to the 
aircraft, accomplish the following:
    (a) For flight-operable APU's, within 24 months after the 
effective date of this airworthiness directive (AD), install an 
exhaust centerbody in accordance with AlliedSignal Aerospace Service 
Bulletin (SB) No. GTCP85-49-A6831, dated March 17, 1994, or SB No. 
GTCP85-49-6919, dated May 17, 1994, as applicable.
    (b) For APU's that are ground-operable only, within 36 months 
after the effective date of this AD, install an exhaust centerbody 
in accordance with AlliedSignal Aerospace SB No. GTCP85-49-6919, 
dated May 17, 1994.
    (c) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Los Angeles Aircraft Certification 
Office. The request should be forwarded through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, Los Angeles Aircraft Certification Office.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Los Angeles Aircraft Certification 
Office.

    (d) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the aircraft to a location where 
the requirements of this AD can be accomplished.

    Issued in Burlington, Massachusetts, on July 21, 1994.
Jay J. Pardee,
Manager, Engine and Propeller Directorate,
Aircraft Certification Service.
[FR Doc. 94-18362 Filed 7-27-94; 8:45 am]
BILLING CODE 4910-13-P