[Federal Register Volume 61, Number 133 (Wednesday, July 10, 1996)]
[Proposed Rules]
[Pages 36310-36311]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-17534]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-ANE-08]
RIN 2120-AA64
Airworthiness Directives; AlliedSignal Inc. TFE731 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. TFE731 series
turbofan engines. This proposal would require removal from service of
certain low pressure turbine (LPT) seal plates prior to accumulating
the new, reduced cyclic life limit, and replacement with serviceable
LPT seal plates. This proposal is prompted by a report that the
machined LPT seal plate geometry did not meet the design intent due to
drawing ambiguity. The actions specified by the proposed AD are
intended to prevent fatigue cracking and subsequent uncontained failure
of an LPT seal plate.
DATES: Comments must be received by September 9, 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. 96-ANE-08, 12 New England
Executive Park, Burlington, MA 01803-5299. Comments may also be
submitted to the Rules Docket by using the following Internet address:
epd-adcomments@mail.hq.faa.gov''. 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: Joseph Costa, Aerospace Engineer, Los
Angeles Aircraft Certification Office, FAA, Transport Airplane
Directorate, 3960 Paramount Blvd., Lakewood, CA 90712-4137; telephone
(310) 627-5246; 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 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 96-ANE-08.'' The postcard will be date stamped and
returned to the commenter.
[[Page 36311]]
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. 96-ANE-08, 12 New England Executive Park,
Burlington, MA 01803-5299.
Discussion
The Federal Aviation Administration (FAA) has received a report
that on certain AlliedSignal Inc. TFE731-2A, -3C and -3CR series
turbofan engines the machined low pressure turbine (LPT) seal plate
geometry did not meet the design intent due to drawing ambiguity. This
drawing ambiguity affected all seal plates, Part Number (P/N) 3073552-2
and P/N 3074053-1. Stress analysis of these seal plates indicated that
a reduction in the FAA-approved low cycle fatigue (LCF) life limit was
necessary. This condition, if not corrected, could result in fatigue
cracking and subsequent uncontained failure of an LPT seal plate.
The FAA has reviewed and approved the technical contents of
AlliedSignal Inc. Service Bulletin (SB) No. TFE731-72-3573, dated
August 15, 1995, that describes procedures for removal from service of
certain part numbered LPT seal plates and replacement 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 require removal from service LPT seal plates, Part
Number (P/N) 3073552-2 and P/N 3074053-1, prior to accumulating the
new, reduced cyclic life limit of 3,700 cycles since new (CSN), and
replacement with serviceable parts. The actions would be required to be
accomplished in accordance with the SB described previously.
The FAA estimates that 268 engines installed on aircraft of U.S.
registry would be affected by this proposed AD, that it would take
approximately 1 work hour during scheduled maintenance to accomplish
the proposed actions, and that the average labor rate is $60 per work
hour. Required parts would cost approximately $5,000 per engine. Based
on these figures, the total cost impact of the proposed AD on U.S.
operators is estimated to be $1,356,080.
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. 96-ANE-08.
Applicability: AlliedSignal Inc. Models TFE731-2A, -3C and -3CR
series turbofan engines, with low pressure turbine (LPT) seal
plates, Part Number (P/N) 3073552-2 and P/N 3074053-1, installed.
These aircraft are installed on but not limited to Cessna Model 650
Citation III and Israel Aircraft Industries Model 1125 Westwind
Astra aircraft.
Note: This airworthiness directive (AD) applies to each engine
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 engines 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 (c) 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 engine from the
applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent fatigue cracking and subsequent uncontained failure
of an LPT seal plate, accomplish the following:
(a) Prior to accumulating 3,700 cycles since new (CSN) on LPT
seal plates, P/N 3073552-2 and 3074053-1, remove from service these
LPT seal plates, and replace with serviceable parts, in accordance
with the Accomplishment Instructions of AlliedSignal Inc. Service
Bulletin (SB) No. TFE731-72-3573, dated August 15, 1995.
(b) This action establishes a new, reduced cyclic life limit of
3,700 CSN for LPT seal plates, P/N 3073552-2 and P/N 3074053-1.
(c) 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.
(d) 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 June 11, 1996.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 96-17534 Filed 7-9-96; 8:45 am]
BILLING CODE 4910-13-U
