[Federal Register Volume 59, Number 228 (Tuesday, November 29, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-29304]


[[Page Unknown]]

[Federal Register: November 29, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-ANE-42]

 

Airworthiness Directives; AlliedSignal Inc. TFE731-3 Series 
Turbofan Engines

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 Turbine Engine Company) TFE731-3 series turbofan engines. This 
proposal would require the removal of suspect low pressure turbine 
(LPT) disks due to their susceptibility to creep fatigue. This proposal 
is prompted by reports of LPT disks that have separated through the 
disk web due to creep fatigue. The actions specified by the proposed AD 
are intended to prevent an LPT disk web separation, which may result in 
an uncontained engine failure and damage to the aircraft.

DATES: Comments must be received by January 30, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 94-ANE-42, 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 Inc., Aviation Services Division, Data 
Distribution, Dept. 64-3/2102-1M, P.O. Box 29003, Phoenix, AZ 85038-
9003; telephone (602) 365-2548. 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: Joseph Costa, Aerospace Engineer, Los 
Angeles Aircraft Certification Office, FAA, Transport Airplane 
Directorate, 3229 East Spring Street, Long Beach, CA 90806-2425; 
telephone (310) 988-5246; fax (310) 988-5210.

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 94-ANE-42.'' 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. 94-ANE-42, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    The Federal Aviation Administration (FAA) has received reports of 
three low pressure turbine (LPT) disks that have separated through the 
disk web due to creep fatigue on the AlliedSignal Inc. (formerly 
Garrett Turbine Engine Company) Models TFE731-3 and -3B turbofan 
engines. Two of the three disk failures were uncontained. Metallurgical 
examination of the failed second stage LPT disks revealed that two heat 
treatment production processes created a microstructure more 
susceptible to creep fatigue cracking. Both production processes 
affected AlliedSignal Inc. TFE731-3 series engines' first and second 
stage LPT disks. The FAA has determined that this microstructure in the 
AlliedSignal Inc. TFE731-3 series disks contributed to the separations. 
In addition, other factors contributed to the separations, such as 
engine misassembly, excessive seal clearance, and mismachining. This 
microstructural condition, if not corrected, could result in an LPT 
disk web separation, which may result in an uncontained engine failure 
and damage to the aircraft.
    The FAA has reviewed and approved the technical contents of 
AlliedSignal Inc. Alert Service Bulletin (ASB) No. TFE731-A72-3544, 
dated October 8, 1993, and ASB No. TFE731-A72-3557, dated May 12, 1994, 
that describe procedures for removal and replacement of specific serial 
numbered first and second stage LPT disks.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of this same type design, the 
proposed AD would require removal of suspect disks due to their 
susceptibility to creep fatigue cracking and disk separation. The 
actions would be required to be accomplished in accordance with the 
service bulletin described previously.
    There are approximately 350 engines with the affected serial 
numbered disks in the worldwide fleet. The FAA estimates that 175 
engines installed on aircraft of U.S. registry would be affected by 
this proposed AD, that it would take approximately 10 work hours per 
engine to accomplish the proposed actions, and that the average labor 
rate is $55 per work hour. Required parts would cost approximately 
$18,000 per engine. Based on these figures, the total cost impact of 
the proposed AD on U.S. operators is estimated to be $3,256,000.
    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. 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:

AlliedSignal Inc.: Docket No. 94-ANE-42.

    Applicability: AlliedSignal Inc. (formerly Garret Turbine Engine 
Company) TFE731-3, -3A, -3AR, -3B, -3BR, and -3R turbofan engine 
models installed on but not limited to Avions Marcel Dassault Falcon 
50, Lockheed 1329-23, -25 series (731 Jetstar, Jetstar II), Israel 
Aircraft Industries (IAI) Ltd. 1124 (Westwind), Raytheon Corporate 
Jets Inc. (formerly British Aerospace) (BAe) DH/HS/BH 125 series, 
Learjet 55 series, Cessna 650 Citation III, VI, Sabreliner NA-265 
series (Sabreliner 65). This airworthiness directive (AD) is not 
applicable to TFE731-3A and TFE731-3AR-200G engines installed on IAI 
1125 Westwind Astra aircraft.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent a low pressure turbine (LPT) disk web separation, 
which may result in an uncontained engine failure and damage to the 
aircraft, accomplish the following:
    (a) Remove from service first and second stage LPT disks, with 
Part Numbers (P/N) 3072351-(), 3072542-(), 3073113-(), and 3073114-
(), where () denotes any dash number, identified by serial number in 
the Compliance Sections of AlliedSignal Aerospace Alert Service 
Bulletin (ASB) No. TFE731-A72-3544, dated October 8, 1993, and 
AlliedSignal Aerospace ASB No. TFE731-A72-3557, dated May 12, 1994, 
within 1500 hours time in service (TIS) after the effective date of 
this airworthiness directive (AD), or at the next removal of the LPT 
assembly, whichever occurs first, in accordance with the 
Accomplishment Instructions of AlliedSignal Aerospace ASB No. 
TFE731-A72-3544, dated October 8, 1993, and AlliedSignal Aerospace 
ASB No. TFE731-A72-3557, dated May 12, 1994, and replace with 
serviceable disks.
    (b) 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.

    (c) 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 November 22, 1994.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 94-29304 Filed 11-28-94; 8:45 am]
BILLING CODE 4910-13-U