Airworthiness Directives; AlliedSignal Aerospace GTCP85 Series Auxiliary Power Units

[Federal Register Volume 60, Number 63 (Monday, April 3, 1995)]
[Rules and Regulations]
[Pages 16780-16782]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-7682]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-ANE-17; Amendment 39-9182; AD 95-07-03]


Airworthiness Directives; AlliedSignal Aerospace GTCP85 Series 
Auxiliary Power Units

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to AlliedSignal Aerospace (formerly Garrett Auxiliary Power 
Division and Garrett Turbine Engine Co.) GTCP85 series auxiliary power 
units (APU), that requires modifying the APU to install an exhaust 
centerbody. This amendment 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 this AD are 
intended to prevent an axially uncontained APU failure and damage to 
the aircraft.

DATES: Effective May 3, 1995.

    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 3, 1995.

ADDRESSES: The service information referenced in this AD 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 Federal Aviation Administration (FAA), New 
England Region, Office of the Assistant Chief Counsel, 12 New England 
Executive Park, Burlington, MA; or at the Office of the Federal 
Register, 800 North Capitol Street NW., suite 700, Washington, DC.

[[Page 16781]] 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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an 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) was published in the Federal 
Register on July 28, 1994 (59 FR 38384). That action proposed to 
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. These actions would be 
performed in accordance with AlliedSignal Aerospace Alert Service 
Bulletin (ASB) No. GTCP85-49-A6831, dated March 17, 1994, applicable to 
APU's installed on McDonnell Douglas DC-9/MD-80 series aircraft, and 
AlliedSignal Aerospace Service Bulletin (SB) No. GTCP85-49-6919, dated 
May 17, 1994, applicable to APU's installed on several other aircraft 
makes and models.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter states that the APU's installed on Boeing 737 series 
aircraft should not be affected by this AD because APU turbine rotor 
axial uncontainment does not pose a hazard to Boeing 737 series 
aircraft. The FAA concurs and has revised the AD accordingly.
    One commenter states that the APU's installed on British Aerospace 
BAC 1-11 series aircraft should also not be affected by this AD because 
APU turbine rotor axial uncontainment does not pose a hazard to British 
Aerospace BAC 1-11 series aircraft. The FAA concurs and has revised the 
AD accordingly.
    One commenter states that the AD should be applicable only to APU's 
with the cast material MAR-M-247 turbine wheel, as only these turbine 
wheels have experienced uncontained failures. The FAA concurs and the 
applicability paragraph of this final rule has been revised 
accordingly.
    Two commenters state that the AD should clearly specify the APU 
model numbers affected and agree with the model numbers listed in the 
applicable service bulletins. The FAA concurs and the applicability 
paragraph of this final rule has been revised accordingly.
    One commenter states that the AD should not be applicable to APU's 
installed on Boeing 727 aircraft, as the APU is ground operable only. 
The FAA does not concur. An APU turbine wheel axial uncontainment may 
pose an unsafe condition even with the aircraft on the ground.
    One commenter states that the AlliedSignal Aerospace ASB No. 
GTCP85-49-A6707, mandated by AD 93-07-13, provides adequate containment 
capability, and that requiring implementation of AlliedSignal Aerospace 
SB No. GTCP85-49-6919 is unnecessary. The FAA does not concur. 
Airworthiness directive 93-07-13 mandates compliance with Garrett SB 
No. GTCP85-49-A6706, not AlliedSignal Aerospace ASB No. GTCP85-49-A6707 
(Garrett has recently undergone a name change to AlliedSignal 
Aerospace). Even reading the comment as referring to AlliedSignal 
Aerospace ASB No. GTCP85-49-A6707, that SB only addresses radial, not 
axial, uncontainment. AlliedSignal Aerospace SB No. GTCP85-49-6919 
addresses axial uncontainment.
    One commenter states that the final rule should allow use of 
subsequent revisions to the SB's in order to avoid unnecessary 
alternate method of compliance requests. The FAA does not concur. If 
the SB's incorporated by reference in this AD are further revised, 
those revisions can be reviewed by the FAA in advance of publication 
and authorized as constituting alternate methods of compliance, thereby 
alleviating the need for each individual operator to obtain a separate 
approval to use the revised SB. Until those future revisions exist, 
however, the FAA cannot incorporate them into this AD.
    One commenter states that the AD should not be applicable to APU's 
with the standard two-piece turbine wheel. The two-piece turbine wheel 
has not experienced the failure mode addressed in the AD. The FAA 
concurs and has revised the applicability paragraph to limit the AD to 
APU's equipped with one-piece cast turbine wheels.
    Two commenters concur with the rule as proposed.
    Since issuance of the NPRM, the FAA has increased its labor 
estimate to $60 per work hour. The economic analysis of this AD has 
been revised accordingly.
    In addition, AlliedSignal Aerospace has issued Revision 1 to SB No. 
GTCP85-49-6919, and ASB No. GTCP85-49-A6831, both dated January 15, 
1995. This final rule now references these revised service documents.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.
    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 will be affected by this AD, that it will 
take approximately 5 work hours per APU to accomplish the proposed 
actions, and that the average labor rate is $60 per work hour. Required 
parts will 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 AD on U.S. operators is estimated 
to be $7,041,450.
    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.
List of Subjects in 14 CFR Part 39

    Air Transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety. [[Page 16782]] 

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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:

95-07-03  AlliedSignal Aerospace: Amendment 39-9182. Docket 94-ANE-
17.

    Applicability: AlliedSignal Aerospace (formerly Garrett 
Auxiliary Power Division and Garrett Turbine Engine Co.) GTCP85 
series auxiliary power units (APU's) with model numbers listed in 
AlliedSignal Aerospace Service Bulletin (SB) No. GTCP85-49-6919, 
Revision 1, dated January 15, 1995, except those APU's installed on 
Boeing 737 and British Aerospace BAC 1-11 series aircraft; and Alert 
Service Bulletin (ASB) No. GTCP85-49-A6831, Revision 1, dated 
January 15, 1995, having a one-piece cast turbine rotor with part 
numbers (P/N) 3842072-1, -2, -3, and P/N 3604604-1, -2, -3, P/N 
3606982-1, and P/N 96895-1 through -8. These APU's are installed on 
but not limited to Boeing 707 series and 727 series aircraft; 
Lockheed L382 series aircraft; and McDonnell Douglas DC-8-70 series 
and DC-9/MD-80 series aircraft.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent an axially 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 ASB No. 
GTCP85-49-A6831, Revision 1, dated January 15, 1995, or ASB No. 
GTCP85-49-A6831, dated March 17, 1994; or SB No. GTCP85-49-6919, 
Revision 1, dated January 15, 1995, 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, 
Revision 1, dated January 15, 1995, or SB No. GTCP85-49-6919, dated 
May 17, 1994.
    (c) No action is required if the APU is installed on a Boeing 
737 or British Aerospace BAC 1-11 series aircraft until the APU is 
removed and installed on a different type aircraft.
    (d) 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.

    (e) 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.
    (f) The installation of the exhaust center body shall be done in 
accordance with the following service documents:

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                       Document No.                          Pages       Revision                Date           
----------------------------------------------------------------------------------------------------------------
ASB No. GTCP85-49-A6831                                                                                         
  Revision Transmittal Sheet..............................        1  1..............  January 15, 1995.         
                                                                  1  1..............   January 15, 1995.        
                                                                2-5  Original.......  May 17, 1994.             
                                                                  6  1..............  January 15, 1995.         
                                                                7-8  Original.......  May 17, 1994.             
                                                               9-10  1..............  January 15, 1995.         
Total pages: 11.                                                                                                
SB No. GTCP85-49-6919.....................................        1  1..............  January 15, 1995.         
                                                                  2  Original.......  May 17, 1994.             
                                                                  3  1..............  January 15, 1995.         
                                                                  4  Original.......  May 17, 1994.             
                                                                  5  1..............  January 15, 1995.         
                                                                  6  Original.......  May 17, 1994.             
                                                               7-10  1..............  January 15, 1995.         
Total Pages: 10.                                                                                                
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    This incorporation by reference was approved by the Director of 
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51. Copies may be obtained from AlliedSignal Aerospace 
Services, P.O. Box 52170, Phoenix, AZ 85072-2170, Attn: Dept. 65-71, 
Mailstop 1802-AA. Copies may be inspected at the FAA, New England 
Region, Office of the Assistant Chief Counsel, 12 New England 
Executive Park, Burlington, MA; or at the Office of the Federal 
Register, 800 North Capitol Street NW., suite 700, Washington, DC.
    (g) This amendment becomes effective on May 3, 1995.
    Issued in Burlington, Massachusetts, on March 23, 1995.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 95-7682 Filed 3-31-95; 8:45 am]
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