[Federal Register Volume 67, Number 60 (Thursday, March 28, 2002)]
[Proposed Rules]
[Pages 14889-14891]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-7416]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NE-01-AD]
RIN 2120-AA64


Airworthiness Directives; Hamilton Sundstrand Power Systems 
(Formerly Sundstrand Power Systems, Turbomach, and Solar) T-62T Series 
Auxiliary Power Units

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The Federal Aviation Administration (FAA) proposes to adopt a 
new airworthiness directive (AD) that is applicable to Hamilton 
Sundstrand Power Systems (formerly Sundstrand Power Systems, Turbomach, 
and Solar) T-62T series auxiliary power units (APU's) with compressor 
wheel part number (P/N) 100636-1 installed. This proposal would require 
the replacement of compressor wheels P/N 100636-1. This proposal is 
prompted by a manufacturer's stress analysis that indicates stress 
levels high enough to initiate and drive crack growth in these 
compressor wheels. The actions specified by the proposed AD are 
intended to mandate the replacement of the affected compressor wheels, 
which if not replaced, could result in uncontained compressor wheel 
failure and damage to the airplane.

DATES: Comments must be received by May 28, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 2002-NE-01-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location, by appointment, between 8:00 a.m. and 4:30 p.m., Monday 
through Friday, except Federal holidays. Comments may also be sent via 
the Internet using the following address: ``[email protected]''. 
Comments sent via the Internet must contain the docket number in the 
subject line.
    The service information referenced in the proposed rule may be 
obtained from Hamilton Sundstrand Power Systems, Technical Publications 
Department, P.O. Box 7002, Rockford, IL, 61125-7002; telephone (815) 
623-5983; fax (815) 966-8525. This information may be examined, by 
appointment, at the FAA, New England Region, Office of the Regional 
Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Roger Pesuit, Aerospace Engineer, Los 
Angeles Aircraft Certification Office, FAA, Transport Airplane 
Directorate, 3960 Paramount Blvd., Lakewood, CA 90712-4137; telephone 
(562) 627-5251, fax (562) 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

[[Page 14890]]

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 action 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 action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2002-NE-01-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRM's

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 2002-NE-01-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    Hamilton Sundstrand Power Systems recently informed the FAA that 
models T-62T-2C, T-62T-25, T-62T-29, and T-62T-39 APU's with compressor 
wheel P/N 100636-1 installed, have high probability of uncontained 
compressor wheel failure caused by low-cycle fatigue. Several low-cycle 
fatigue failures of compressor wheels on the larger, Hamilton 
Sundstrand Power Systems model T-62T-40C APU, triggered the 
manufacturer to perform analysis of the geometrically similar 
compressor wheel P/N 100636-1. Although no uncontained failures of 
compressor wheel P/N 100636-1 have been known to occur in APU's 
installed on airplanes of U.S. registry, inspections of some compressor 
wheels during maintenance revealed cracks in attachment holes that are 
a precursor to failure. The manufacturer is aware also that four 
compressor wheels of the affected P/N have failed in APU's installed on 
U.S. military aircraft. This condition, if not corrected, could result 
in uncontained compressor wheel failure and damage to the airplane.

FAA's Determination of an Unsafe Condition and Proposed Actions

    Since an unsafe condition has been identified that is likely to 
exist or develop on other aircraft with Hamilton Sundstrand Power 
Systems (formerly Sundstrand Power Systems, Turbomach, and Solar) 
models T-62T-2C, T-62T-25, T-62T-29, and T-62T-39 APU's installed, the 
proposed AD would require replacement at new reduced cycle life limits 
of compressor wheels P/N 100636-1, with compressor wheel P/N 4503164, 
4504174, or M4504174. Two manufactured types of compressor wheel P/N 
100636-1 exist. One type is a cast steel compressor wheel, identifiable 
by a four-digit casting lot vendor identification number, used as a 
prefix to the serial number. The other type is a wrought steel 
compressor wheel, identifiable by a serial number beginning with the 
letter W.
    Cast steel compressor wheel replacement schedule:
     Replace compressor wheels with 2,350 or greater cycles-
since-new (CSN) on the effective date of the proposed AD within 250 
cycles-in-service (CIS) after the effective date of the proposed AD.
     Replace compressor wheels with less than 2,350 CSN on the 
effective date of the proposed AD before accumulating 2,600 CSN.

Wrought steel compressor wheel replacement schedule:

     Replace compressor wheels with 3,600 or greater CSN on the 
effective date of the proposed AD within 500 CIS after the effective 
date of the proposed AD.
     Replace compressor wheels with less than 3,600 CSN on the 
effective date of the proposed AD before accumulating 4,100 CSN.

Economic Analysis

    There are approximately 492 Hamilton Sundstrand Power Systems 
(formerly Sundstrand Power Systems, Turbomach, and Solar) models T-62T-
2C, T-62T-25, T-62T-29, and T-62T-39 APU's of the affected design in 
the worldwide fleet. The FAA estimates that 337 APU's installed on 
airplanes of U.S. registry would be affected by this proposed AD. The 
FAA also estimates that it would take approximately 40 work hours per 
APU to do the proposed actions, and that the average labor rate is $60 
per work hour. The cost of a replacement compressor wheel is estimated 
to be $16,799. Based on these figures, the total cost of the proposed 
AD on U.S. operators is estimated to be $6,470,063.

Regulatory Analysis

    This proposed rule does not have federalism implications, as 
defined in Executive Order 13132, because it would not have a 
substantial direct effect 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. 
Accordingly, the FAA has not consulted with state authorities prior to 
publication of this proposed rule.
    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 adding the following new 
airworthiness directive:

Hamilton Sundstrand Power Systems: Docket No. 2002-NE-01-AD.

    Applicability: This airworthiness directive (AD) is applicable 
to aircraft with Hamilton Sundstrand Power Systems (formerly 
Sundstrand Power Systems, Turbomach, and Solar) models T-62T-2C, T-
62T-25, T-62T-29, and T-62T-39 auxiliary power units (APU's) 
installed that have compressor wheel part number (P/N) 100636-1 
installed. These APU's are installed on, but not limited to, 
Fairchild FH-227, Dassault Falcon 20, Lockheed 1329 series 
(Jetstar), British Aerospace Jetstream 3101, Raytheon Aircraft 
HS125-600,--700,--800, and Sabreliner

[[Page 14891]]

Corporation 60 and 80 aircraft, and Boeing Defense & Space Group 234 
Series Helicopters.

    Note 1: This 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 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 of 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: Compliance with this AD is required as indicated, 
unless already done.
    To replace affected compressor wheels P/N 100636-1, which if not 
replaced, could result in uncontained compressor wheel failure and 
damage to the airplane, do the following.

Cast Steel Compressor Wheel Replacement

    (a) For compressor wheels, P/N 100636-1, made of cast steel, 
identifiable by a four-digit casting lot vendor identification 
number used as a prefix to the serial number, replace compressor 
wheels with compressor wheel P/N 4503164, 4504174, or M4504174 as 
follows:
    (1) Replace cast steel compressor wheels with 2,350 or greater 
cycles-since-new (CSN) on the effective date of this AD within 250 
cycles-in-service (CIS) after the effective date of this AD.
    (2) Replace cast steel compressor wheels with less than 2,350 
CSN on the effective date of this AD before accumulating 2,600 CSN.

Wrought Steel Compressor Wheel Replacement

    (b) For compressor wheels, P/N 100636-1 made of wrought steel, 
identifiable by a serial number beginning with the letter W, replace 
compressor wheels with compressor wheel P/N 4503164, 4504174, or 
M4504174 as follows:
    (1) Replace wrought steel compressor wheels with 3,600 or 
greater CSN on the effective date of this AD within 500 CIS after 
the effective date of this AD.
    (2) Replace wrought steel compressor wheels with less than 3,600 
CSN on the effective date of this AD before accumulating 4,100 CSN.
    (c) Information on procedures for replacing compressor wheel P/N 
100636-1 may be found in Hamilton Sundstrand Power Systems service 
bulletin No. SB-T-62T-49-148, Revision 1, dated December 20, 2001.

Reduced Life Limits

    (d) This AD establishes new cyclic life limits for compressor 
wheels P/N 100636-1, of 2,600 CSN for cast steel compressor wheels 
and 4,100 CSN for wrought steel compressor wheels. Except as 
provided in paragraph (e) of this AD, no alternate life limits for 
these parts may be approved.

Alternative Methods of Compliance

    (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 (ACO). Operators must submit their request through an 
appropriate FAA Principal Maintenance Inspector, who may add 
comments and then send it to the Manager, Los Angeles ACO.

    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 ACO.

Special Flight Permits

    (f) Special flight permits may be issued in accordance with 
Secs. 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 done.

    Issued in Burlington, Massachusetts, on March 20, 2002.
Francis A. Favara,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 02-7416 Filed 3-27-02; 8:45 am]
BILLING CODE 4910-13-U