AD 95-03-15

This amendment adopts a new airworthiness directive (AD), applicable to Textron Lycoming ALF502R series turbofan engines, that reduces the service life for the No. 2 stage turbine disk, reduces the service lives for No. 1 and No. 3 through No. 7 stage compressor rotor disks, and requires a scheduled removal of these disks from service. This amendment is prompted by reports of cracks in disks returned from the field and in disks tested by the manufacturer. The actions specified by this AD are intended to prevent disk failure resulting in a possible uncontained engine failure.

Final rule.

95-03-15 Textron Lycoming: Amendment 39-9151. Docket 92-ANE-11.
Applicability: Textron Lycoming ALF502R series turbofan engines installed on but not limited to British Aerospace BAe-146 aircraft.
Compliance: Required as indicated, unless accomplished previously.
To prevent No. 2 stage turbine disk, and No. 1 and No. 3 through No. 7 stage compressor rotor disk, failure resulting in possible uncontained engine failure, accomplish the following:
(a) Remove from service No. 2 stage turbine disks, P/Ns 2-121-058-18, 2-121-058-20, and 2-121-058-R24, in accordance with the schedule defined in paragraph B(1) of Table 1 of Textron Lycoming Service Bulletin (SB) ALF502R 72-281, dated February 7, 1992, and replace with a disk with cycle accumulation no greater than the reduced service life limit of 10,000 cycles.
(b) Remove from service No. 1 stage compressor rotor disks, P/N 2-101-331-04, in accordance with paragraph A(1) of Table 1 of Textron Lycoming SB No. ALF502R 72-281,dated February 7, 1992, and replace with a disk with cycle accumulation no greater than the reduced service life limit of 12,500 cycles.
(c) Remove from service No. 3 stage compressor rotor disks, P/Ns 2-101-263-02, 2-101- 263-05, 2-101-263-06, 2-101-263-09, and 2-101-263-R10, in accordance with paragraph A(2) of Table 1 of Textron Lycoming SB No. ALF502R 72-281, dated February 7, 1992, and replace with a disk with cycle accumulation no greater than the reduced service life limit of 11,800 cycles.
(d) Remove from service No. 4 stage compressor rotor disks, P/Ns 2-100-042-03, 2-100- 042-07, 2-100-042-09, and 2-100-042-R08, in accordance with paragraph A(3) of Table 1 of Textron Lycoming SB No. ALF502R 72-281, dated February 7, 1992, and replace with a disk with cycle accumulation no greater than the reduced service life limit of 9,000 cycles.
(e) Remove from service No. 5 stage compressor rotor disks, P/Ns 2-100-043-01, 2-100- 043-07, 2-100-043-09, and 2-100-043-R08, in accordance with paragraph A(4) of Table 1 of Textron Lycoming SB No. ALF502R 72-281, dated February 7, 1992, and replace with a disk with cycle accumulation no greater than the reduced service life limit of 12,300 cycles.
(f) Remove from service No. 6 stage compressor rotor disks, P/Ns 2-100-044-01, 2-100- 044-05, 2-100-044-07, and 2-100-044-R06, in accordance with paragraph A(5) of Table 1 of Textron Lycoming SB No. ALF502R 72-281, dated February 7, 1992, and replace with a disk with cycle accumulation no greater than the reduced service life limit of 12,500 cycles.
(g) Remove from service No. 7 stage compressor rotor disks, P/Ns 2-100-045-01, 2-100- 045-05, 2-100-045-07, and 2-100-045-R06, in accordance with paragraph A(6) of Table 1 of Textron Lycoming SB No. ALF502R 72-281, dated February 7, 1992, and replace with a disk with cycle accumulation no greater than the reduced service life limit of 9,200 cycles.
(h) 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, Engine Certification Office. The request should be forwarded through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office. NOTE: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.
(i) The actions required by this AD shall be done in accordance with the following Textron Lycoming service bulletin:

Document No.
Pages
Date
ALF502R 72-281
1-5
February 7, 1992
Total pages: 5.

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 Textron Lycoming, 550 Main Street, Stratford, CT 06497. Copies may be inspected at the FAA, New England Region, Office of the Assistant Chief 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.
(j) This amendment becomes effective on May 8, 1995.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to Textron Lycoming ALF502R series turbofan engines was published in the Federal Register on March 16, 1993 (58 FR 14185). That action proposed to reduce the service life for the No. 2 stage turbine disk, reduce the service lives for No. 1 and No. 3 through No. 7 stage compressor rotor disks, and require a scheduled removal of these disks from service in accordance with Textron Lycoming Service Bulletin (SB) ALF502R 72-281, dated February 7, 1992.
The compliance section of this final rule has been revised to specify the reduced service lives for each affected disk, to clarify that the reduced service lives are the new life limits.
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. The FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously.
On October 28, 1994, AlliedSignal Inc. purchased the turbine engine product line of Textron Lycoming, but as of this date the anticipated name change on the type certificate for the ALF502R series engines has not occurred.
There are approximately 700 Textron Lycoming ALF502R series turbofan engines of the affected design in the worldwide fleet. The FAA estimates that 200 engines installed on aircraft of U.S. registry will be affected by this AD. The required reduction in service life will cost $41,400 per engine based on the cost of a new disk prorated over the reduced service life as compared to the current service life. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $8,280,000.
The regulations adopted herein will 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 final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
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 it 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 39Air 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 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89. 39.13 - [AMENDED]
2. Section 39.13 is amended by adding the following new airworthiness directive: