Airworthiness Directives; Allison Engine Company, Inc. AE 3007A and AE 3007C Turbofan Engines

[Federal Register Volume 64, Number 150 (Thursday, August 5, 1999)] [Proposed Rules] [Pages 42622-42623] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 99-20183]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NE-15-AD] RIN 2120-AA64

Airworthiness Directives; Allison Engine Company, Inc. AE 3007A and AE 3007C 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 Allison Engine Company, Inc. AE 3007A and AE 3007C series turbofan engines. This proposal would require removing certain turbine wheels from service before exceeding new, reduced cyclic life limits. This proposal is prompted by a refined life analysis that was performed by the manufacturer. The actions specified by the proposed AD are intended to prevent an uncontained turbine wheel failure, which could result in damage to the airplane.

DATES: Comments must be received by October 4, 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-15-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. The service information referenced in the proposed rule may be obtained from Rolls-Royce Allison, P.O. Box 420, Speed Code U-15, Indianapolis, IN 46206-0420, telephone (317) 230-6674. This information may be examined at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

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-15-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. 99-NE-15-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

Allison Engine Company, Inc., also known as Rolls-Royce Allison, the manufacturer of AE 3007A and AE 3007C series turbofan engines, suspects that certain turbine wheels may have tungsten contamination. The suspect turbine wheels were manufactured between January 26, 1993, and August 27, 1993. The manufacturer has also re-evaluated the effect of a surface treatment on the service life of a wheel. A refined life analysis, which took into account both the possibility of tungsten inclusions and the surface treatment, revealed new maximum service lives that are significantly lower than those previously published. This condition, if not corrected, could result in an uncontained turbine wheel failure, which could result in damage to the airplane. The FAA has reviewed and approved the technical contents of Rolls- Royce Alert Service Bulletin (ASB) AE 3007A-A-72-105 and AE 3007C-A-72- 105, dated January 29,1999, that lists new, reduced engine cyclic life limits for affected turbine wheels. Rolls-Royce Allison produces and distributes the service documents that cover the Allison Engine Co. AE3007A and AE3007C turbofan engines. Since an unsafe condition has been identified that is likely to exist or develop on other engines of the same type design, the proposed AD would require removing affected turbine wheels from service before exceeding new, reduced cyclic life limits. The actions would be required to be accomplished in accordance with the ASB described previously. There are approximately 325 engines of the affected design in the worldwide fleet. The FAA estimates that 260

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engines installed on aircraft of U.S. registry would be affected by this proposed AD, that it would take approximately 63 work hours per engine to accomplish the proposed actions, and that the average labor rate is $60 per work hour. The estimated cost of the lost cycles due to the reduction of the engine cycle life limit is $57,800 per engine. Required parts would cost approximately $54,020 per engine. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $15,028,000. The manufacturer of the affected turbine wheels has advised the FAA that it may defray the cost of the reduced life limits, thus reducing the overall cost to operators. 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. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

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

Allison Engine Company, Inc.: Docket No. 99-NE-15-AD.

Applicability: Allison Engine Company, Inc. AE 3007A and AE 3007C series turbofan engines, installed on, but not limited to Cessna Aircraft Company 750 series airplanes and Empresa Brasileira de Aeronautica S.A. (Embraer) EMB-145 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: Required as indicated, unless accomplished previously. To prevent an uncontained turbine wheel failure, which could result in damage to the airplane, accomplish the following: (a) Remove stage 1 turbine wheels, part numbers (P/N's) 23065891 and 23062373, and replace with new or serviceable parts as follows: (1) For stage 1 turbine wheels with serial numbers (SN's) listed in table 5 of Rolls-Royce Alert Service Bulletin (ASB) AE 3007A-A- 72-105 and AE 3007C-A-72-105, dated January 29, 1999, replace before accumulating 9,000 engine cycles since new (CSN). (2) For all other stage 1 turbine wheels SN's, replace before accumulating 13,100 engine CSN. (b) Remove stage 2 turbine wheels, P/N's 23065892 and 23063462, and replace with new or serviceable parts as follows: (1) For stage 2 turbine wheels with SN's listed in table 6 of Rolls-Royce ASB AE 3007A-A-72-105 and AE 3007C-A-72-105, dated January 29,1999, replace before accumulating 7,800 engine CSN. (2) For all other stage 2 turbine wheels SN's, replace before accumulating 8,400 engine CSN. (c) This AD establishes new cyclic life limits for the turbine wheels identified in paragraphs (a) and (b) of this AD. Except in accordance with paragraph (d) of this AD, no alternative life limits may be approved for the turbine wheels identified in paragraphs (a) and (b) of this AD. (d) 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.

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

Issued in Burlington, Massachusetts, on July 30, 1999. Jorge A. Fernandez, Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service. [FR Doc. 99-20183 Filed 8-4-99; 8:45 am] BILLING CODE 4910-13-P