[Federal Register Volume 62, Number 52 (Tuesday, March 18, 1997)]
[Proposed Rules]
[Pages 12774-12776]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-6745]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 97-ANE-03]
RIN 2120-AA64


Airworthiness Directives; AlliedSignal Inc. TSCP700-4B 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 supersedure of an existing 
airworthiness directive (AD), applicable to AlliedSignal Inc. (formerly 
AirResearch and Garrett) TSCP700-4B and -5 Series Auxiliary Power 
Units, that currently requires restretching the first stage low 
pressure compressor (LPC) tie rods, or replacing affected disks at or 
before 8,000 cycles since new (CSN). This action would eliminate the 
option of restretching the tie rods, and would require removing from 
service affected disks, replacing them with serviceable parts, and 
establishing a life limit of 8,000 CSN for affected disks. This 
proposal is prompted by a report of a first stage LPC disk rim 
separation due to low cycle fatigue on an APU that had its tie rods 
restretched in accordance with the current AD. The actions specified by 
the proposed AD are intended to prevent first stage LPC disk rim 
separation due to low cycle fatigue, which could result in an 
uncontained APU failure and damage to the aircraft.

DATES: Comments must be received by May 19, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 97-ANE-03, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: ``<a href="/cdn-cgi/l/email-protection#f3cade9297def9969d949a9d9683819c83b3959292dd979c87dd949c85">9-ad-
<span class="__cf_email__" data-cfemail="d8bdb6bfb1b6bda8aab7a898beb9b9f6bcb7acf6bfb7ae">[email protected]</span></a>''. Comments sent via the Internet must contain 
the docket number in the subject line. 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

[[Page 12775]]

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 97-ANE-03.'' 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. 97-ANE-03, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    On October 31, 1988, the Federal Aviation Administration (FAA) 
issued airworthiness directive AD 88-24-07, Amendment 39-6062 (53 FR 
46439, November 17, 1988), applicable to AlliedSignal Inc. (formerly 
AirResearch and Garrett) TSCP700-4B and -5 series auxiliary power units 
(APUs), to require restretching the tie rods, or replacing affected 
disks at or before 8,000 cycles since new (CSN). That action was 
prompted by reports of compressor tie rod separation in the event of 
disk rim separation. That condition, if not corrected, could result in 
compressor tie rod separation in the event of disk rim separation, 
which could result in an uncontained APU failure and damage to the 
aircraft.
    Since the issuance of that AD, the FAA has received a report that a 
first stage LPC disk, installed on an APU with restretched tie rods in 
accordance with AD 88-24-07, experienced an uncontained disk rim 
separation at 9,408 CSN and caused aircraft damage. The FAA has 
therefore determined that it is necessary to eliminate the tie rod 
restretching option and institute the life limit of 8,000 CSN for all 
affected disks.
    The FAA has reviewed and approved the technical contents of 
AlliedSignal Service Bulletin (SB) No. TSCP700-49-7266, dated June 16, 
1996, that describes procedures for calculating when to remove from 
service affected disks, and describes procedures for removing from 
service affected disks, and replacing them with serviceable parts.
    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 88-24-07 to eliminate the option of 
restretching the tie rods, and require removing from service affected 
disks in accordance with a schedule derived from calculations in the 
SB, replacing affected disks with serviceable parts, and establishing a 
life limit of 8,000 CSN for affected disks.
    The FAA estimates that 100 APUs installed on aircraft of U.S. 
registry would be affected by this proposed AD, that it would take no 
additional work hours per APU to accomplish the proposed actions if the 
actions are accomplished during APU overhaul, 8 work hours to 
accomplish the proposed actions if the actions are not accomplished 
during APU overhaul, and that the average labor rate is $60 per work 
hour. Based on these figures, and that the work would not be performed 
during overhaul, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $48,000.
    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-6062 (53 FR 
46439, November 17, 1988) and by adding a new airworthiness directive 
to read as follows:

AlliedSignal Inc.: Docket No. 97-ANE-03. Supersedes AD 88-24-07, 
Amendment 39-6062.

    Applicability: AlliedSignal Inc. (formerly AirResearch and 
Garrett) TSCP700-4B and -5 auxiliary power units (APUs), with first 
stage low pressure compressor (LPC) disks, Part Number (P/N) 
3606429-1, installed on but not limited to Airbus A300 series, and 
McDonnell Douglas DC-10 and KC-10 (military) series aircraft.

    Note 1: 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 (e) 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 first stage LPC disk rim separation due to low cycle 
fatigue, which could result in an uncontained APU failure and damage 
to the aircraft, accomplish the following:
    (a) Remove from service first stage LPC disks, P/N 3606429-1, in 
accordance with the schedule derived from calculations in paragraph 
C.(3) of AlliedSignal Service Bulletin (SB) No. TSCP700-49-7266, 
dated June 16, 1996, and the removal procedures described in the 
Accomplishment Instructions of that SB, and replace with serviceable 
parts.
    (b) Except as provided in paragraph (a), this AD establishes a 
life limit of 8,000 cycles

[[Page 12776]]

since new (CSN) for first stage LPC disks, P/N 3606429-1.
    (c) The definition of a disk cycle may be found in the 
applicable AlliedSignal Inc. APU Component Maintenance Manual.
    (d) Except as provided in paragraph (e) of this AD, no 
alternative replacement times may be approved for first stage LPC 
disks, P/N 3606429-1.
    (e) 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 2: 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.

    (f) 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 February 25, 1997.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 97-6745 Filed 3-17-97; 8:45 am]
BILLING CODE 4910-13-U


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