03-11267. Airworthiness Directives; Rolls-Royce plc RB211 Trent 800 Series Turbofan Engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for Rolls-Royce plc (RR) RB211 Trent 875-17, Trent 877-17, Trent 884-17, Trent 892-17, Trent 892B-17, and Trent 895-17 turbofan engines with intermediate pressure (IP) turbine discs, part numbers (P/Ns) FK21117 and FK33083 installed. This proposed AD would require removal from service of these IP turbine discs in accordance with newly established reduced turbine disc life limits. This proposed AD is prompted by reports of two IP turbine blade release incidents as a result of dust caps separating from the blades, and subsequent improved modeling analysis. The actions specified in this proposed AD are intended to prevent uncontained IP turbine disc failure and damage to the airplane.

DATES:

We must receive any comments on this proposed AD by July 7, 2003.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD:

• Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2003-NE-08-AD, 12 New England Executive Park, Burlington, MA 01803-5299.
• By fax: [phone].
• By e-mail: [e-mail].

You may examine the AD docket, by appointment, at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

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

We invite you to submit any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “AD Docket No. 2003-NE-08-AD” in the subject line of your comments. If you want us to acknowledge receipt of your mailed comments, send us a self-addressed, stamped postcard with the docket number written on it; we will date-stamp your postcard and mail it back to you. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. If a person contacts us through a nonwritten communication, and that contact relates to a substantive part of this proposed AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You may get more information about plain language at http://www.plainlanguage.gov.

Examining the AD Docket

You may examine the AD Docket (including any comments and service information), by appointment, between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. See ADDRESSES for the location.

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 875-17, Trent 877-17, Trent 884-17, Trent 892-17, Trent 892B-17, and Trent 895-17 turbofan engines. The CAA advises that reports were received of two IP turbine blade release incidents as a result of dust caps separating from the blades. Subsequently, the manufacturer applied improved modeling techniques for analysis, which revealed higher than predicted operating temperatures at the IP turbine disc rim and surrounding area due to inflow of annulus exhaust gases. As a result of this analysis, the manufacturer has assigned new lower life limits of 8,600 cycles-since-new (CSN) for IP turbine disc P/N FK21117, and 3,000 CSN for IP turbine disc P/N FK33083.

FAA's Determination and Requirements of the Proposed AD

These RR RB211 Trent 875-17, Trent 877-17, Trent 884-17, Trent 892-17, Trent 892B-17, and Trent 895-17 turbofan engines, manufactured in the U.K., 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 us informed of the situation described above. We have examined the CAA's findings, 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. Therefore, we are proposing this AD, which would require replacing IP turbine discs, P/Ns FK21117 and FK33083, at or before reaching the new reduced life cycle limits of 8,600 CSN and 3,000 CSN respectively.

Changes to 14 CFR Part 39—Effect on the Proposed AD

On July 10, 2002, we published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's AD system. This regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.

Costs of Compliance

There are approximately 350 RR RB211 Trent 875-17, Trent 877-17, Trent 884-17, Trent 892-17, Trent 892B-17, and Trent 895-17 turbofan engines of the affected design in the worldwide fleet. We estimate that 114 engines installed on airplanes of U.S. registry would be affected by this proposed AD. We also estimate that the prorated cost of the life reduction per engine would be approximately $246,000. Based on these figures, the total cost of the proposed AD is estimated to be $28,044,000.

Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

For the reasons discussed above, I certify that the 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. Would not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

We prepared a summary of the costs to comply with this proposal and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include “AD Docket No. 2003-NE-08-AD” in your request.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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. The FAA amends § 39.13 by adding the following new airworthiness directive:

Rolls-Royce plc: Docket No. 2003-NE-08-AD.

Comments Due Date

(a) The Federal Aviation Administration must receive comments on this airworthiness directive (AD) action by July 7, 2003.

Affected ADs

(b) None.

Applicability

(c) This AD is applicable to Rolls-Royce plc (RR) RB211 Trent 875-17, Trent 877-17, Trent 884-17, Trent 892-17, Trent 892B-17, and Trent 895-17 turbofan engines with intermediate pressure (IP) turbine discs P/Ns FK21117 and FK33083 installed. These engines are installed on, but not limited to Boeing 777 airplanes.

Unsafe Condition

(d) This AD was prompted by reports of two IP turbine blade release incidents as a result of dust caps separating from the blades. Subsequently, the manufacturer applied improved modeling techniques for analysis, which revealed higher than predicted operating temperatures at the IP turbine disc rim and surrounding area due to inflow of annulus exhaust gases. The actions specified in this AD are intended to prevent uncontained IP turbine disc failure and damage to the airplane.

Compliance

(e) Compliance with this AD is required as indicated, unless already done.

(f) To prevent uncontained IP turbine disc failure and damage to the airplane, do the following:

(1) Remove IP turbine disc P/N FK21117 from service at or before accumulating 8,600 cycles-since-new (CSN), and remove IP turbine disc P/N FK33083 from service at or before accumulating 3,000 CSN.

(2) After the effective date of this AD, do not install any IP turbine disc P/N FK21117, that exceeds 8,600 CSN, or any IP turbine disc P/N FK33083, that exceeds 3,000 CSN.

Alternative Methods of Compliance

(g) Alternative methods of compliance must be requested in accordance with 14 CFR part 39.19, and must be approved by the Manager, Engine Certification Office, Engine and Propeller Directorate, FAA.

Material Incorporated by Reference

(h) None.

Related Information

(i) The subject of this AD is addressed in CAA airworthiness directive 002-01-2003, dated January 14, 2003.

Issued in Burlington, Massachusetts, on April 30, 2003.

Francis A. Favara,

Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.