AD 2000-23-11

This amendment adopts a new airworthiness directive (AD), applicable to Rolls-Royce (RR) plc. Spey 555-15, -15H, -15N, and -15P turbofan engines, that requires modification of the low pressure (LP) turbine stage 2 nozzle guide vane (NGV) support ring seal assembly. This amendment is prompted by two instances of disk drive arm damage. In both cases, heavy damage to the stage 1 LP turbine-to-stage 2 LP turbine disk drive arm occurred as a result of an out-of-balance condition following the failure of a stage 2 LP turbine blade. The actions specified by this AD are intended to prevent damage to the disk drive arm which could result in loss of stage 1 LP turbine-to- stage 2 LP turbine disk drive, a turbine overspeed condition, and possible uncontained disk failure and damage to the airplane.

Final rule.

2000-23-11 Rolls-Royce: Amendment 39-11981. Docket 2000-NE-03-AD.

Applicability: Rolls-Royce (RR) plc. Spey 555-15, -15H, -15N, and -15P turbofan engines. These engines are installed on but not limited to Fokker F.28 Mark 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 (b) 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 damage to the disk drive arm which could result in loss of stage 1 LP turbine-to- stage 2 LP turbine disk drive, a turbine overspeed condition and possible uncontained disk failure, and damage to the airplane, do the following:

Rework Instructions
(a) Within three years after the effective date of this AD, rework the low pressure (LP) turbine stage 2 nozzle guide vane (NGV) support ring seal assembly in accordance with paragraphs 2.A. through 2.C. of the Accomplishment Instructions of RR service bulletin (SB) No. Sp 72-1063, dated May 1999.

Alternative Methods of Compliance
(b) 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
(c) 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.

(d) The rework shall be done in accordance with the following Rolls-Royce service bulletin: (SB) No. Sp 72-1063, dated May 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, PO Box 31, Derby, England, DE248BJ; telephone no. 011-44-1332-242-424; fax no. 011-44-1332-245-418. 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
(e) This amendment becomes effective on December 20, 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 (RR) plc. Spey 555-15, -15H, -15N, and -15P turbofan engines was published in the Federal Register on July 7, 2000 (65 FR 41884). That action proposed to require modification of the low pressure (LP) turbine stage 2 nozzle guide vane (NGV) support ring seal assembly in accordance with Service Bulletin (SB) No. Sp 72-1063, dated May 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 Impact
There are approximately 310 engines of the affected design in the worldwide fleet. The FAA estimates that 60 engines installed on aircraft of U.S. registry would be affected by this AD. It will take approximately 2.0 work hours per engine to accomplish the proposed actions. The average labor rate is $60 per work hour. Since this action is a rework of existing parts, there is no required parts cost. Based on these figures, the FAA estimates the total cost impact of the proposed AD on U.S. operators to be $7,200.

Regulatory Impact
This proposed rule does not have federalism implications, as defined in Executive Order No. 13132, because it would not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the [the next 2 typos I think are in the boilerplate. I keep seeing them]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 proposed rule.

For the reasons discussed above, I certify that this action (1) is not a "significantregulatory 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 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 Code of Federal 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: