AD 2000-13-01

This amendment adopts a new airworthiness directive (AD) that is applicable to Allison Engine Company, Inc. AE 3007A and AE 3007C series turbofan engines. This AD requires the removal from service of certain turbine wheels before exceeding new, reduced cyclic life limits. This amendment is prompted by a refined life analysis that was performed by the manufacturer. The actions specified by this AD are intended to prevent an uncontained turbine wheel failure, which could result in damage to the airplane.

Final rule.

2000-13-01 Allison Engine Company, Inc.: Amendment 39-11800. 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 (d) 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:
Remove and Replace
(a) Remove stage 1 turbine wheels, part numbers (P/Ns) 23065891 and 23062373, and replace with new or serviceable parts as follows:
(1) For stage 1 turbine wheels with serial numbers (SNs) 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 wheel SNs with P/Ns 23065891 and 23062373, replace before accumulating 13,100 engine CSN.
(b) Remove stage 2 turbine wheels, P/Ns 23065892 and 23063462, and replace with new or serviceable parts as follows:
(1) For stage 2 turbine wheels with SNs 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 wheel SNs with P/Ns 23065892 and 23063462, replace before accumulating 8,400 engine CSN.
Alternative Life Limits
(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.
Alternative Method of Compliance
(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.
Special Flight Permits
(e) Special flight permits may be issued in accordance with 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.
Documents Incorporated by Reference
(f) This AD references Rolls-Royce Alert Service Bulletin AE 3007A-A-72-105/AE 3007C-A-72-105, dated January 29, 1999. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Rolls-Royce Allison, P.O. Box 420, Indianapolis, IN 46206-0420; telephone: (888) 255-4766. Copies may be inspected at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.
Effective Date
(g) This amendment becomes effective on September 1, 2000.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) applicable to Allison Engine Company, Inc. AE 3007A and AE 3007C series turbofan engines was published in the Federal Register on August 5, 1999 (64 FR 42622). That action proposed to require the removal of certain turbine wheels from service before exceeding new, reduced cyclic life limits listed in Rolls-Royce Alert Service Bulletin (ASB) AE 3007A-A-72-105/AE 3007C-A-72-105, dated January 29, 1999.
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.
Support for the Rule
One commenter supports the proposed rule as written.
Part Numbers
One commenter requests the addition of part numbers (P/N) to the compliance section. The commenter states that the way the NPRM is written, paragraphs (a)(2) and (b)(2) could be interpreted to mean that all stage 1 and stage 2 turbine wheels, respectively, should have lower lives. In fact, the life reduction is limited to a few part numbers. The addition of the affected part numbers would prevent confusion.
The FAA agrees. To eliminate confusion, paragraph (a)(2) of the compliance section of the final rule has been revised to specify P/Ns 23065891 and 23062373. Paragraph (b)(2) of the compliance section of the final rule has been revised to specify P/Ns 23065892 and 23063462.
Conclusion
After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.
Economic Analysis
There are approximately 325 engines of the affected design in the worldwide fleet. The FAA estimatesthat 260 engines installed on aircraft of U.S. registry will be affected by this AD, that it will take approximately 63 work hours per engine to accomplish the required 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. Based on these figures, the total cost impact of the 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.
Regulatory Impact
This rule does not have federalism implications, as defined in Executive Order 13132, because it does 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 rule. For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action and is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part39) 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.
39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: