[Federal Register Volume 66, Number 36 (Thursday, February 22, 2001)]
[Proposed Rules]
[Pages 11126-11127]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-4393]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NE-41-AD]
RIN 2120-AA64


Airworthiness Directives; Rolls-Royce Corporation (Formerly 
Allison Engine Company) AE 3007A and AE 3007C Model 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 Rolls-Royce (RR) Corporation 
(formerly Allison Engine Company) AE 3007A and AE 3007C model engines 
with high pressure turbine (HPT) 1st to 2nd stage turbine spacer part 
number (P/N) 23058369 installed. This proposal would require removal 
and replacement of the HPT 1st to 2nd stage turbine spacer P/N 23058369 
before it reaches its new reduced engine cycle life limit. This 
proposal is prompted by the results of a detailed component analysis 
that indicates that the HPT 1st to 2nd stage turbine spacer stresses 
are higher than predicted. The actions specified by the proposed AD are 
intended to prevent HPT 1st to 2nd stage turbine spacer failure which 
could result in an uncontained engine failure and damage to the 
airplane.

DATES: Comments must be received by April 23, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 2000-NE-41-AD, 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.

FOR FURTHER INFORMATION CONTACT: Michael Downs, Aerospace Engineer, 
Chicago Aircraft Certification Office, FAA, Small Airplane Directorate, 
2300 E. Devon Ave., Des Plaines, IL 60018; telephone (847) 294-7870, 
fax (847) 294-7834.

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 action 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 proposal must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NE-41-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRM's

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 2000-NE-41-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

[[Page 11127]]

Discussion

    The manufacturer's original analysis of the HPT 1st to 2nd stage 
turbine spacer P/N 23058369 low-cycle fatigue life computed a cleared 
life of 20,000 cycles. When the part number was reanalyzed for low-
cycle fatigue life, it was determined that the stress concentration 
factor in the cooling slots was incorrect and the stresses associated 
with the forward cooling slots were higher than predicted. The updated 
analysis indicates that the low-cycle fatigue life limit of P/N 
23058369 should be reduced from 20,000 cycles to 9,400 cycles.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other RR AE 3007A and AE 3007C model engines of the 
same type design, the proposed AD would require removal and replacement 
of HPT 1st to 2nd stage turbine spacer P/N 23058369 before it reaches 
its new reduced engine cycle life limit. This condition, if not 
corrected, could result in HPT 1st to 2nd stage turbine spacer failure, 
which could result in an uncontained engine failure and damage to the 
airplane.

Economic Impact

    There are approximately 378 engines of the affected design in the 
worldwide fleet. The FAA estimates that 300 engines installed on 150 
airplanes of U.S. registry would be affected by this proposed AD. It 
will take approximately 13 work hours per engine to accomplish the 
removal and replacement of the affected HPT 1st to 2nd stage spacer. 
The 13 work hours cited include teardown and rebuilding from the module 
level, but not engine removal. Engines are rarely scheduled off-wing 
solely for the purpose of replacement of time-expired components.The 
average labor rate is $60 per work hour. Required parts will cost 
approximately $10,012 per engine. Based on these figures, the FAA 
estimates the total cost impact of the proposed AD on U.S. operators, 
to be $3,237,600. Because most of the fleet field parts are below the 
new value, special scheduling should not be required.

Regulatory Impact

    This proposed rule does not have federalism implications, as 
defined in Executive Order 13132, because it would not have a 
substantial direct effect 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. 
Accordingly, the FAA has not consulted with state authorities prior to 
publication of this proposed rule.
    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Rolls-Royce Corporation:  Docket No. 2000-NE-41-AD.

    Applicability: This AD is applicable to Rolls-Royce (RR) 
Corporation (formerly Allison Engine Company) AE 3007A and AE 3007C 
model engines with high pressure turbine (HPT) 1st to 2nd stage 
turbine spacer part number (P/N) 23058369 installed. These engines 
are installed on but not limited to Empresa Brasileira de 
Aeronautica S.A. (EMBRAER) EMB-145 and Cessna 750 series airplanes.

    Note 1: 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 request 
approval for an alternative method of compliance in accordance with 
paragraph (c) of this AD. The request should include an assessment 
of the effect of the modification, alteration, or repair on the 
unsafe condition addressed by this AD; and, if the unsafe condition 
has not been eliminated, the request should include specific 
proposed actions to address it.

Compliance

    Compliance with this AD is required as indicated, unless 
accomplished previously.
    To prevent HPT 1st to 2nd stage turbine spacer-failure, which 
could result in an uncontained engine failure and damage to the 
airplane, accomplish the following:

New Reduced Engine Cycle Life Limit

    (a) For all RR Corporation AE 3007A and AE 3007C model engines 
with HPT 1st to 2nd stage turbine spacer, P/N 23058369 installed, 
remove spacer before reaching the new reduced engine cycle life 
limit of 9,400 cycles and replace with a serviceable part.
    (b) Revise the airworthiness limitations section of the 
Instruction for Continued Airworthiness, as follows: P/N 
23058369=9,400 cycles.

Alternative Methods of Compliance

    (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, Chicago Aircraft Certification 
Office. Operators shall submit their request through an appropriate 
FAA Principal Maintenance Inspector, who may add comments and then 
send it to the Manager, Chicago Aircraft Certification Office (ACO).

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Chicago ACO.

Special Flight Permits

    (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 February 13, 2001.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 01-4393 Filed 2-21-01; 8:45 am]
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