[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: 
``[email protected]''. 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