[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]
BILLING CODE 4910-13-U