[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]
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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).
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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
