[Federal Register Volume 61, Number 59 (Tuesday, March 26, 1996)]
[Proposed Rules]
[Pages 13113-13115]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-7245]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-ANE-68]


Airworthiness Directives; AlliedSignal, Inc. TSCP700-4B, -4E, and 
-5 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, Inc. (formerly 
Garrett) Models TSCP700-4B, -4E, and -5 auxiliary power units (APU's). 
This proposal would require removal from service of certain high 
pressure turbine (HPT) disks identified by serial number, and 
replacement with serviceable parts. This proposal is prompted by the 
discovery of a material defect in certain HPT disk forgings that may 
result in HPT disk rupture prior to reaching the disk cyclic life 
limit. The actions specified by the proposed AD are intended to prevent 
an HPT disk rupture.

DATES: Comments must be received by May 28, 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. 95-ANE-68, 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 Engines, P.O. Box 52181, Phoenix, AZ 85072-
2181; telephone (800) 338-3378, fax (602) 231-4402. 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

[[Page 13114]]
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 95-ANE-68.'' 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. 95-ANE-68, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    The Federal Aviation Administration (FAA) received a report from 
the manufacturer that a material defect exists in certain forgings of 
high pressure turbine (HPT) disks installed on AlliedSignal, Inc. 
(formerly Garrett) Models TSCP700-4B, -4E, and -5 auxiliary power units 
(APU's). Analysis indicates that HPT disks forged from this material 
may rupture prior to reaching the disk cyclic life limit of 30,000 
cycles since new (CSN). This condition, if not corrected, could result 
in an HPT disk rupture.
    The FAA has reviewed and approved the technical contents of 
AlliedSignal Aerospace Service Bulletin (SB) No. TSCP700-49-A7168, 
dated November 7, 1995, that identifies by serial number HPT disks that 
may have been forged with a material defect.
    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 removal from service of certain HPT disks 
identified by serial number, and replacement with serviceable parts, 
prior to accumulating 7,500 CSN, or 3 years after the effective date of 
this AD, whichever occurs first. The FAA determined this calendar end-
date based upon the effect of the material defect on the HPT disks' 
cyclic life. In addition, the FAA considered the rate of cyclic 
accumulation on disks in service. The actions would be required to be 
accomplished in accordance with the SB described previously.
    There are approximately 31 APU's of the affected design in the 
worldwide fleet. The FAA estimates that 20 APU's installed on aircraft 
of U.S. registry would be affected by this proposed AD, and that no 
additional work hours would be required if the disk is replaced during 
overhaul. The manufacturer has advised the FAA that they will supply 
required parts at no charge to the operator. The FAA has therefore 
determined that this AD would impose no additional cost on U.S. 
operators.
    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.


Sec. 39.13  [Amended]

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

AlliedSignal, Inc.: Docket No. 95-ANE-68.

    Applicability: AlliedSignal, Inc. (formerly Garrett) Models 
TSCP700-4B, -4E, and -5 auxiliary power units (APU's), with high 
pressure turbine (HPT) disks identified by serial number in 
AlliedSignal Aerospace Service Bulletin (SB) No. TSCP700-49-A7168, 
dated November 7, 1995. These APU's are installed on, but not 
limited to, McDonnell Douglas DC-10, KC-10 (military), and MD-11 
series, and Airbus A300 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 APU's that have been 
modified, altered, or repaired so that the performance of the 
requirements of this AD is affected, the owner/operator must use the 
authority provided in paragraph (d) to request approval from the 
Federal Aviation Administration (FAA). This approval may address 
either no action, if the current configuration eliminates the unsafe 
condition, or different actions necessary to address the unsafe 
condition described in this AD. Such a request should include an 
assessment of the effect of the changed configuration on the unsafe 
condition addressed by this AD. In no case does the presence of any 
modification, alteration, or repair remove any APU from the 
applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent an HPT disk rupture, accomplish the following:
    (a) Prior to accumulating 7,500 cycles since new (CSN), or 3 
years after the effective date of this AD, whichever occurs first, 
remove from service affected HPT disks and replace with a 
serviceable part.
    (b) The definition of a disk cycle may be found in the 
applicable AlliedSignal, Inc. APU Component Maintenance Manual.
    (c) Auxiliary Power Unit maintenance records may be used to 
determine if the HPT disk installed in the APU has a serial number 
listed in AlliedSignal Aerospace SB No. TSCP700-49-A7168, dated 
November 7, 1995.
    (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.


[[Page 13115]]

    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.

    Issued in Burlington, Massachusetts, on March 12, 1996.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 96-7245 Filed 3-25-96; 8:45 am]
BILLING CODE 4910-13-P