Airworthiness directives: Allison Engine Co.,

[Federal Register: October 12, 1999 (Volume 64, Number 196)]

[Proposed Rules]

[Page 55196-55197]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr12oc99-34]

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).

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- adcomment@faa.gov''. 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 filedin 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. 99-26574Filed10-8-99; 8:45 am]

   BILLING CODE 4910-13-P