AD 2000-08-01

This amendment adopts a new airworthiness directive (AD) that is applicable to Rolls-Royce plc Tay 650-15 series turbofan engines. This AD requires the establishment of cyclic life limits for stage 1 high pressure turbine (HPT) and stage 1 low pressure turbine (LPT) disks operating under new flight plan profiles. This amendment is prompted by reports that, on some engines, cracks in the stage 1 HPT and stage 1 LPT disks could initiate and propagate at a faster rate than forecast under the flight plan profiles originally published at the time the engine design was certified. The actions specified by this AD are intended to prevent crack initiation and propagation leading to turbine disk failure, which could result in an uncontained engine failure and damage to the aircraft.

Final rule.

2000-08-01 Rolls-Royce plc: Amendment 39-11687. Docket 99-NE-61-AD.
Applicability: Rolls-Royce plc (R-R) Tay 650-15 series turbofan engines, with stage 1 high pressure turbine (HPT) disks, part numbers (P/Ns) JR32013 and JR33838, and stage 1 low pressure turbine (LPT) disks, P/N JR32318A. These engines are installed on but not limited to Fokker F.28 Mark 0100 (F100) series aircraft.
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 unsafecondition 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 crack initiation and propagation leading to turbine disk failure, which could result in an uncontained engine failure and damage to the aircraft, accomplish the following:
Flight Plan Profile C
(a) Remove from service stage 1 HPT disks, P/Ns JR32013 and JR33838, and stage 1 LPT disks, P/N JR32318A, operated under flight plan profile C, as defined in the R-R Tay Engine Manual, 70-01-10, pages 1-10, prior to accumulating 18,000 cycles-since-new (CSN), and replace with serviceable parts.
Flight Plan Profile D
(b) Remove from service stage 1 HPT disks, P/Ns JR32013 and JR33838, and stage 1 LPT disks, P/N JR32318A, operated under flight plan profile D, as defined in the R-R Tay Engine Manual, 70-01-10, pages 1-10, prior to accumulating 14,250 CSN, and replace with serviceable parts.
Alternative Methods of Compliance
(c) 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 (ECO). Operators shall submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO.
Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO.
Special Flight Permits
(d) Special flight permits may be issued in accordance with sections 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.
Incorporation by Reference Material
(e) The actions of this AD shall be done in accordance with R-R Service Bulletin TAY-72-1479, dated July 20, 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 plc, P.O. Box 31, Derby, DE24 8BJ, UK, telephone 011-44-1332-242424 . 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 of This AD
(f) This amendment becomes effective on June 19, 2000.

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 Rolls-Royce plc (R-R) Tay 650-15 series turbofan engines was published in the Federal Register on January 12, 2000 (65 FR 1831). That action proposed to establish life limits for stage 1 HPT and stage 1 LPT disks operated under the new flight plan profiles, C and D; require the removal from service of stage 1 HPT and stage 1 LPT disks prior to reaching new, lower cyclic life limits; and replace those disks with serviceable parts in accordance with R-R Service Bulletin TAY-72-1479, dated July 20, 1999.
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 as proposed. Economic Analysis
There are approximately 242 engines of the affected design in the worldwide fleet. The FAA estimates that three engines installed on aircraft of U.S. registry will be affected by this AD, and that the prorated life reduction would cost $26,658 per engine. Based on these figures, the total cost impact of the proposed AD on US operators is estimated to be $79,974. Regulatory Impact
This rule does not have federalism implications, as defined in Executive Order (EO) No. 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 EO No. 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 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. 39.13 [Amended] 2. Section 39.13 is amended by adding the following new airworthiness directive: