[Federal Register Volume 60, Number 39 (Tuesday, February 28, 1995)]
[Proposed Rules]
[Pages 10811-10812]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-4852]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-ANE-56]


Airworthiness Directives; Textron Lycoming ALF502L 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 Textron Lycoming ALF502L series 
turbofan engines. This proposal would establish reduced retirement life 
limits for stage 1 and stage 3-7 compressor disks, and stage 2 turbine 
disks, and provide a drawdown schedule for disks already beyond the 
reduced retirement life limits. This proposal is prompted by new life 
analyses of these components. The actions specified by the proposed AD 
are intended to prevent disk failure, which could result in an inflight 
engine shutdown and extensive engine damage.

DATES: Comments must be received by May 1, 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-56, 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 Engines, 550 Main Street, Stratford, CT 
06497; telephone (203) 385-1470. 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: Eugene Triozzi, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7148, fax (617) 238-7199.

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-56.'' 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-56, 12 New England Executive Park, 
Burlington, MA 01803-5299. [[Page 10812]] 

Discussion

    Textron Lycoming conducted new life analyses for various components 
in ALF502L series turbofan engines. Textron Lycoming has determined 
that stage 1 and stage 3-7 compressor disks, and stage 2 turbine disks 
require reduced retirement life limits. No failures have occurred in 
service on the ALF502L series engines, but inspections of these 
components from ALF502R series engines have found cracks prior to 
attaining current service retirement lives. This condition, if not 
corrected, could result in disk failure, which could result in an 
inflight engine shutdown and extensive engine damage.
    On October 28, 1994, AlliedSignal Inc. purchased the turbine engine 
product line of Textron Lycoming, but as of this date the anticipated 
name change on the type certificate for the ALF502L series engines has 
not occurred. However, the service bulletins (SB) issued for these 
engines now bear the title, ``AlliedSignal Engines.'' The Federal 
Aviation Administration (FAA) has reviewed and approved the technical 
contents of AlliedSignal Engines SB No. ALF 502 72-0004, Revision 12, 
dated November 30, 1994, that describes reduced retirement lives for 
affected components; and AlliedSignal Engines SB No. ALF502L 72-281, 
dated November 30, 1994, that describes a drawdown schedule for disks 
already beyond the reduced retirement life limits.
    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 establish reduced retirement life limits for stage 1 
and stage 3-7 compressors disks, and stage 2 turbine disks, and provide 
a drawdown schedule for disks already beyond the reduced retirement 
life limits. The actions would be required to be accomplished in 
accordance with the service bulletins described previously.
    There are approximately 184 engines of the affected design in the 
worldwide fleet. The FAA estimates that 50 engines installed on 
aircraft of U.S. registry would be affected by this proposed AD, and 
that the prorated reduced service life cost based on the cost of a new 
disk would be approximately $16,400 per engine. Based on these figures, 
the total cost impact of the proposed AD on U.S. operators is estimated 
to be $820,000.
    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:

Textron Lycoming: Docket No. 94-ANE-56.
    Applicability: Textron Lycoming ALF502L, L-2, L-2A, L-2C, and L-
3 turbofan engines installed on but not limited to Canadair 
Challenger CL600 series aircraft.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent disk failure, which could result in an inflight 
engine shutdown and extensive engine damage, accomplish the 
following:
    (a) Remove from service stage 1 and stage 3-7 compressor disks, 
and stage 2 turbine disks, in accordance with the drawdown schedule 
and procedures described in AlliedSignal Engines Service Bulletin 
(SB) No. ALF502L 72-281, dated November 30, 1994.
    (b) This AD establishes new, reduced retirement life limits for 
stage 1 and stage 3-7 compressor disks, and stage 2 turbine disks, 
in accordance with AlliedSignal Engines SB No. ALF 502 72-0004, 
Revision 12, dated November 30, 1994.
    (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, Engine 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, Engine Certification Office.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Engine Certification Office.

    Issued in Burlington, Massachusetts, on February 16, 1995.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 95-4852 Filed 2-27-95; 8:45 am]
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