[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]
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