Airworthiness directives: Royce plc,

[Federal Register: January 12, 2000 (Volume 65, Number 8)]

[Proposed Rules]

[Page 1831-1833]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr12ja00-30]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NE-61-AD]

RIN 2120-AA64

Airworthiness Directives; Rolls-Royce plc Tay 650-15 Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Rolls-Royce plc Tay 650-15 series turbofan engines. This proposal would establish 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 proposal is prompted by reports that on some engines disk cracks in the stage 1 HPT and stage 1 LPT 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 the proposed 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.

DATES: Comments must be received by March 13, 2000.

ADDRESSES: Submit comments to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-61-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be submitted to the Rules Docket by using the following Internet address: ``9-ane- adcomment@faa.gov''. Comments may be inspected at this location between 8:00a.m. and 4:30 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: James Lawrence, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone 781- 238-7176, fax 781-238-7199.

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

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they may desire. Communications should identify the Rules Docket number and be submitted 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 filedin 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-61-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

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-61-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom (UK), recently notified the Federal Aviation Administration (FAA) that an unsafe condition may exist on Rolls-Royce plc (R-R) Tay 650-15 series turbofan engines. The CAA advises that on engines installed on Fokker F.28 Mark 0100 (F100) series airplanes cracks 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. These published flight plan profiles, A and B, provide cyclic life limits for affected engine components, specifically the stage 1 high pressure turbine (HPT), part numbers (P/Ns) JR32013 and JR33838, and stage 1 low pressure turbine (LPT) disks, P/N JR32318A. Rolls-Royce has developed two new flight plan profiles, C and D, and published life limits for the stage 1 HPT and stage 1 LPT disks associated with operating under those new flight plan profiles. The FAA has determined that three domestic engines must be categorized as having operated under flight plan profiles C and D, as described in the R-R Tay Engine Manual, 70-01-10, pages 1-10. Engines operating under flight plan profiles C and D have faster HPT and LPT disk crack initiation and propagation rates than engines operated under flight plan profiles A or B. Therefore, the FAA has determined that the stage 1 HPT and stage 1 LPT disks must be removed from these three domestic engines at lower cyclic life limits than if operated under flight plan profiles A or B. This condition, if not corrected, could result in crack initiation and propagation leading to turbine disk failure, which could result in an uncontained engine failure and damage to the aircraft.

CAA Airworthiness Directive (AD) Differences with This Proposed Rule

The CAA issued AD 004-07-99 on July 20, 1999, in order to assure the airworthiness of R-R Tay 650-15 series turbofan engines in the UK. The CAA AD published a drawdown plan which allows operators with engines near or slightly over the reduced life limit to remove those disks from service in a scheduled, but safe manner. The three engines operated on aircraft of US registry do not have disks that are approaching the new, lower cyclic life limits, therefore, this proposed rule does not contain a drawdown schedule, but only establishes the cyclic life limits for the new flight plan profiles.

Bilateral Airworthiness Agreement

This engine model is manufactured in the UK and is type certificated for operation in the United States under the provisions of Sec. 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the CAA has kept the FAA informed of the situation described above. The FAA has examined the findings of the CAA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Proposed Actions

Since an unsafe condition has been identified that is likely to exist or develop on other engines of the same type design registered in the United States, the proposed AD would establish life limits for stage 1 HPT and stage 1 LPT disks operated under the new flight plan profiles, C and D, require removing from service stage 1 HPT and stage 1 LPT disks prior to reaching new, lower cyclic life limits, and replacing those disks with serviceable parts.

Economic Analysis

There are approximately 242 engines of the affected design in the worldwide fleet. The FAA estimates that 3 engines installed on aircraft of U.S. registry would be affected by this proposed AD, that the prorated life reduction would cost $26,658 per engine. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $79,974.

Regulatory Impact

This proposal 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 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 proposal.

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.

   [[Page 1833]]

   Sec. 39.13 [Amended]

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

   Rolls-Royce plc: Docket No. 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 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 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 AD, if any, may be obtained from the ECO.

   Ferry Flights

   (d) Special flight permits may be issued in accordance with Secs. 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.

   Issued in Burlington, Massachusetts, on January 5, 2000. Thomas A. Boudreau, Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.

   [FR Doc. 00-601Filed1-11-00; 8:45 am]

   BILLING CODE 4910-13-U