[Federal Register Volume 61, Number 156 (Monday, August 12, 1996)]
[Proposed Rules]
[Pages 41751-41753]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-20396]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-ANE-15]
RIN 2120-AA64
Airworthiness Directives; AlliedSignal Inc. 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 supersedure of an existing
airworthiness directive (AD), applicable to AlliedSignal Inc. (formerly
Garrett Auxiliary Power Division) GTCP85 Series auxiliary power units
(APUs), that currently requires removing the existing turbine wheel
shroud and installing one constructed of Hastelloy ``S'' material, or
installing a containment augmentation ring. This action would delete
the option of installing a turbine shroud constructed of Hastelloy
``S'' material. This proposal is prompted by a report of insufficient
APU containment capability with the Hastelloy ``S'' shroud alone
installed. The actions specified by the proposed AD are intended to
prevent turbine shroud fragments from exiting the APU and puncturing
the APU compartment, which could result in reduced fire extinguishing
capability in the APU compartment.
DATE: Comments must be received by October 11, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), New England Region, Office of the Assistant Chief
Counsel, Attention: Rules Docket No. 96-ANE-15, 12 New England
Executive Park, Burlington, MA 01803-5299. Comments may also be
submitted to the Rules Docket by using the following Internet address:
``[email protected]''. All comments must contain the
Docket No. in the subject line of the comment. 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, Attn: Data Distribution, M/S 64-
3/2101-201, P.O. Box 29003, Phoenix, AZ 85038-9003; telephone (602)
365-2493, fax (602) 365-5577. 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, 3960 Paramount Blvd., Lakewood, CA 90712-4137; telephone
(310) 627-5245; fax (310) 627-5210.
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 96-ANE-15.'' 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. 96-ANE-15, 12 New England Executive Park,
Burlington, MA 01803-5299.
Discussion
On April 13, 1993, the Federal Aviation Administration (FAA) issued
airworthiness directive (AD) 93-07-13, Amendment 39-8545 (58 FR 21917,
April 26, 1993), applicable to AlliedSignal Inc. (formerly Garrett
Auxiliary Power Division) GTCP85 Series auxiliary power units (APUs),
to require removing the existing turbine wheel shroud and installing
one constructed of Hastelloy ``S'' material, or installing a
containment
[[Page 41752]]
augmentation ring. That action was prompted by an incident in which the
one-piece cast turbine wheel separated and subsequently impacted the
turbine wheel shroud, fragmenting the shroud into four segments. Two of
these shroud fragments exited the APU. In that instance, the shroud was
constructed of Inconel 718 material, and a containment augmentation
ring, Part Number (P/N) 3612249-1, had been installed. That condition,
if not corrected, could result in turbine shroud fragments exiting the
APU and puncturing the APU compartment, which could result in reduced
fire extinguishing capability in the APU compartment.
Since the issuance of that AD, the FAA received a report that an
APU with turbine shroud constructed of Hastelloy ``S'' material, P/N
3611904-1, experienced an uncontained failure. The FAA's investigation
revealed that the turbine shroud alone may not provide adequate
containment under all conditions, and that a containment augmentation
ring must be added to ensure that engine fragments do not puncture the
APU compartment.
The FAA has reviewed and approved the technical contents of
AlliedSignal Aerospace Alert Service Bulletin (ASB) No. GTCP85-49-
A7189, Revision 1, dated July 19, 1996; and AlliedSignal Aerospace ASB
No. GTCP85-49-A6706, Revision 2, dated November 28, 1994, AlliedSignal
Aerospace ASB No. GTCP85-49-A6706, Revision 1, dated November 12, 1993,
or Garrett ASB No. GTCP85-49-A6706, Original, dated December 7, 1992.
These ASB's describe procedures for installing a containment
augmentation ring.
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 supersede AD 93-07-13 to require installing an
improved containment augmentation ring, P/N 3616426-1, or P/N 3616426-
3, which is a redesigned containment augmentation ring to allow
installation on certain APU's that cannot accept the -1 containment
augmentation ring. The containment augmentation rings, P/Ns 3616426-1
and 3616426-3, improve the containment capability of the APU relative
to the earlier containment augmentation ring, P/N 3612249-1, by
preventing turbine shroud fragments from passing around the containment
augmentation ring. The installation must be accomplished within 24
months after the effective date of this AD, for flight operable APUs,
and within 36 months after the effective date of this AD, for APUs that
are operable on the ground only. The actions would be required to be
accomplished in accordance with the ASB's described previously.
There are approximately 1,050 APU's of the affected design in the
worldwide fleet. The FAA estimates that 350 APU's installed on aircraft
of U.S. registry would be affected by this proposed AD, and that it
would take no additional work hours if the proposed actions are
accomplished when the APU is already disassembled in the shop. Required
parts would cost approximately $1,550 per APU. Based on these figures,
the total cost impact of the proposed AD on U.S. operators is estimated
to be $542,500.
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 USC 106(g), 40113, 44701.
39.13 [Amended]
2. Section 39.13 is amended by removing amendment 39-8545 (52 FR
45163, November 25, 1987) and by adding a new airworthiness directive
to read as follows:
Allied Signal Inc.: Docket No. 96-ANE-15. Supersedes AD 93-07-
13, Amendment 39-8545.
Applicability: AlliedSignal Inc. (formerly Garrett Auxiliary
Power Division) GTCP85 series auxiliary power units (APU's),
incorporating a one-piece cast turbine wheel, Part Numbers (P/Ns)
968095-X, 3604604-X, 3606982-1, or 3842072-X (where ``X'' denotes
any number). These APUs are installed on but not limited to the
following aircraft: British Aerospace BAC 1-11 series; Boeing 707,
727, and 737 series; Lockheed L382 series; and McDonnell Douglas DC-
8-70, DC-9, and MD-88 series aircraft.
Note: This airworthiness directive (AD) applies to each APU
identified in the preceding applicability provision, regardless of
whether it has been modified, altered, or repaired in the area
subject to the requirements of this AD. For APUs that have been
modified, altered, or repaired so that the performance of the
requirements of this AD is affected, the owner/operator must request
approval for an alternative method of compliance in accordance with
paragraph (c) of this AD. The request should include an assessment
of the effect of the modification, alteration, or repair on the
unsafe condition addressed by this AD; and, if the unsafe condition
has not been eliminated, the request should include specific
proposed actions to address it.
Compliance: Required as indicated, unless accomplished
previously.
To prevent turbine shroud fragments from exiting the APU and
puncturing the APU compartment, which could result in reduced fire
extinguishing capability in the APU compartment, accomplish the
following:
(a) For flight operable APUs, within 24 months after the
effective date of this AD, accomplish either of the following:
(1) Install a containment augmentation ring, P/N 3616426-3, in
accordance with AlliedSignal Aerospace Alert Service Bulletin (ASB)
No. GTCP85-49-A7189, Revision 1, dated July 19, 1996; or
(2) Install a containment augmentation ring, P/N 3616426-1, in
accordance with AlliedSignal Aerospace ASB No. GTCP85-49-A6706,
Revision 2, dated November 28, 1994, AlliedSignal Aerospace ASB No.
GTCP85-49-A6706, Revision 1, dated November 12, 1993, or Garrett ASB
No. GTCP85-49-A6706, Original, dated December 7, 1992.
(b) For APUs that are operable on the ground only, within 36
months after the effective date of this AD, accomplish either of the
following:
(1) Install a containment augmentation ring, P/N 3616426-3, in
accordance with AlliedSignal Aerospace ASB No. GTCP85-49-A7189,
Revision 1, dated July 19, 1996; or
(2) Install a containment augmentation ring, P/N 3616426-1, in
accordance with AlliedSignal Aerospace ASB No. GTCP85-49-A6706,
Revision 2, dated November 28, 1994, AlliedSignal Aerospace ASB No.
GTCP85-49-A6706, Revision 1, dated
[[Page 41753]]
November 12, 1993, or Garrett ASB No. GTCP85-49-A6706, Original,
dated December 7, 1992.
(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 31, 1996.
Mark C. Fulmer,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 96-20396 Filed 8-9-96; 8:45 am]
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