03-5691. Airworthiness Directives; Rolls-Royce plc RB211 Trent 800 Series Turbofan Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The Federal Aviation Administration (FAA) proposes to adopt a new airworthiness directive (AD) that is applicable to Rolls-Royce plc (RR) RB211 Trent 875, Trent 877, Trent 884, Trent 892, Trent 892B, and Trent 895 turbofan engines with high pressure (HP) compressor rotor rear stage 5 and 6 discs and cone shafts, part numbers (P/Ns) FK25230 and FK27899 installed. This proposal would require removal from service of these HP compressor rotor rear stage 5 and 6 discs and cone shafts, before reaching newly reduced life limits. This proposal is prompted by three reports of crack indications in the stage 5 and stage 6 blade loading slots, found during engine overhaul. The actions specified by the proposed AD are intended to prevent crack initiation and propagation leading to uncontained disc failure and damage to the airplane.

DATES:

Comments must be received by May 12, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2003-NE-03-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may be inspected at this location, by appointment, between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. Comments may also be sent via the Internet using the following address: “[e-mail]”. Comments sent via the Internet must contain the docket number in the subject line.

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 [phone]; fax [phone].

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 they may desire. Communications should identify the Rules Docket number and be submitted in triplicate 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 action 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 filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2003-NE-03-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRM's

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. 2003-NE-03-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 (U.K.), recently notified the FAA that an unsafe condition may exist on RR RB211 Trent 875, Trent 877, Trent 884, Trent 892, Trent 892B, and Trent 895 turbofan engines. The CAA advises that three HP compressor rotor rear stage 5 and 6 discs and cone shafts, P/Ns FK25230 and FK27899, were found with crack indications in the stage 5 and 6 blade loading slots, during overhaul inspection. The manufacturer's analysis has not yet been able to identify the root cause of these cracks, or to fully explain the crack propagation rate. As a result of the analysis thus far, a new lower life limit of 7,500 cycles-since-new (CSN) has been assigned by the manufacturer to these HP compressor rotor rear stage 5 and 6 discs and cone shafts. This condition, if not corrected, could result in stage 5 and 6 disc crack initiation and propagation leading to uncontained disc failure and damage to the airplane.

Bilateral Agreement Information

These engine models are manufactured in the U.K. and are type certificated for operation in the United States under the provisions of section 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 Requirements of This AD

Since an unsafe condition has been identified that is likely to exist or develop on other RR RB211 Trent 875, Trent 877, Trent 884, Trent 892, Trent 892B, and Trent 895 turbofan engines of the same type design that are used on airplanes registered in the United States, the proposed AD would require replacing HP compressor rotor rear stage 5 and 6 discs and cone shafts, P/Ns FK25230 and FK27899, at or before reaching the new reduced life cycle limit of 7,500 CSN.

Interim Action

These proposed actions are considered interim action and the FAA may take additional actions in the future.

Economic Analysis

There are approximately 350 engines of the affected design in the worldwide fleet. The FAA estimates that 90 engines installed on airplanes of U.S. registry would be affected by this proposed AD. The FAA also estimates that the prorated cost of the life reduction per engine would be approximately $112,195. Based on these figures, the total cost of the proposed AD is estimated to be $10,097,550.

Regulatory Analysis

This proposed rule does not have federalism implications, as defined in Executive Order 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 proposed rule.

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.

§ 39.13

[Amended]

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

Rolls-Royce plc: Docket No. 2003-NE-03-AD.

Applicability: This airworthiness directive (AD) is applicable to Rolls-Royce plc (RR) RB211 Trent 875, Trent 877, Trent 884, Trent 892, Trent 892B, and Trent 895 turbofan engines with high pressure (HP) compressor rotor rear stage 5 and 6 discs and cone shafts, part numbers (P/Ns) FK25230 and FK27899 installed. These engines are installed on, but not limited to Boeing 777 airplanes.

Note 1:

This 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: Compliance with this AD is required as indicated, unless already done.

To prevent stage 5 and 6 disc crack initiation and propagation leading to uncontained disc failure and damage to the airplane, do the following:

(a) Remove HP compressor rotor rear stage 5 and 6 discs and cone shafts, from service at or before accumulating 7,500 cycles-since-new (CSN).

(b) After the effective date of this AD, do not install any HP compressor rotor rear stage 5 and 6 discs and cone shaft, listed in this AD, that exceed 7,500 CSN.

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 must 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 §§ 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be done.

Note 3:

The subject of this AD is addressed in CAA airworthiness directive 002-08-2002, dated November 22, 2002.

Issued in Burlington, Massachusetts, on March 5, 2003.

Jay J. Pardee,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.