[Federal Register Volume 64, Number 196 (Tuesday, October 12, 1999)]
[Proposed Rules]
[Pages 55196-55197]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-26574]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NE-46-AD]
RIN 2120-AA64


Airworthiness Directives; Allison Engine Company AE 3007 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 certain Allison Engine Company AE 
3007 series turbofan engines. This proposal would require removing from 
service certain cone shafts prior to them reaching new cyclic life 
limits, and replacing with serviceable parts. This proposal is prompted 
by additional testing and low cycle fatigue (LCF) life analysis that 
indicates lower cyclic lives than originally determined. The actions 
specified by the proposed AD are intended to prevent LCF failure of 
cone shafts, which could result in an uncontained engine failure and 
damage to the aircraft.

DATES: Comments must be received by December 13, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 99-NE-46-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: ``9-ane-
[email protected]''. Comments sent via the Internet must contain the 
docket number in the subject line. 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: John Tallarovic, Aerospace Engineer, 
Chicago Aircraft Certification Office, FAA, Small Airplane Directorate, 
2300 East Devon Avenue, Des Plaines, IL 60018; telephone (847) 294-
8180, 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 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 99-NE-46-AD.'' 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 Regional Counsel, 
Attention: Rules Docket No. 99-NE-46-AD, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    Allison Engine Company, the manufacturer of models AE 3007A, AE 
3007A1, AE 3007A1/1, AE 3007A1/2, AE 3007A1/3, AE 3007A1/P, and AE 
3007C turbofan engines, recently conducted additional testing and low 
cycle fatigue (LCF) life analysis of cone shafts, part numbers (P/Ns) 
23050728 and 23070729. This testing and analysis revealed maximum 
approved service lives significantly lower than published maximum 
approved service lives. To date, however, no failures of cone shafts 
have been reported. This condition, if not corrected, could result in 
LCF failure of cone shafts, which could result in an uncontained engine 
failure and damage to the aircraft.

Proposed Actions

    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 of cone shafts, P/Ns 
23050728 and 23070729, prior to accumulating new cyclic life limits, 
depending on engine model.

Economic Analysis

    There are approximately 598 engines of the affected design in the 
worldwide fleet. The FAA estimates that 364 engines installed on 
aircraft of U.S. registry would be affected by this proposed AD, that 
it would take approximately 150 work hours per engine to accomplish the 
proposed actions, and that the average labor rate is $60 per work hour. 
Required parts would cost approximately $3,921 per engine. Based on 
these figures, the total cost impact of the proposed AD on US operators 
is estimated to be $4,703,244.

Regulatory Impact

    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

[[Page 55197]]

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:

Allison Engine Company: Docket No. 99-NE-46-AD.

    Applicability: Allison Engine Company Models AE 3007A, AE 
3007A1, AE 3007A1/
1, AE 3007A1/2, AE 3007A1/3, AE 3007A1/
P, and AE 3007C turbofan engines, with cone shafts, part numbers (P/
Ns) 23050728 and 23070729, installed. These engines are installed on 
but not limited to EMBRAER EMB-145 series and Cessna 750 (Citation 
X) 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 (f) 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: Required as indicated, unless accomplished 
previously.
    To prevent low cycle fatigue failure of cone shafts, which could 
result in an uncontained engine failure and damage to the aircraft, 
accomplish the following:

Removal From Service

    (a) For Allison Engine Company models AE 3007A, AE 3007A1, AE 
3007A1/1, AE 3007A1/2, and AE 3007C engines, remove cone shafts from 
service prior to accumulating 7,500 cycles-since-new (CSN), and 
replace with serviceable parts.
    (b) For Allison Engine Company model AE 3007A1/3 engines, remove 
cone shafts from service prior to accumulating 3,500 CSN, and 
replace with serviceable parts.
    (c) For Allison Engine Company model AE 3007A1/P engines, remove 
cone shafts from service prior to accumulating 2,400 CSN, and 
replace with serviceable parts.

New Life Limits

    (d) Paragraphs (a), (b), and (c) of this AD establish new, lower 
life limits for cone shafts, P/Ns 23050728 and 23070729.
    (e) Except for the provisions of paragraph (f) of this AD, no 
cone shafts, P/Ns 23050728 and 23070729, may remain in service 
exceeding the life limits established in paragraphs (a), (b), and 
(c) of this AD.

Alternate Method of Compliance

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

    (g) No special flight permits will be issued.

    Issued in Burlington, Massachusetts, on October 5, 1999.
Diane Romanosky,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 99-26574 Filed 10-8-99; 8:45 am]
BILLING CODE 4910-13-P