2010-7830. Airworthiness Directives; Rolls-Royce plc RB211 Trent 700 and Trent 800 Series Turbofan Engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as: In completing a review of Engine Manual repair/acceptance limits for titanium compressor shafts, Rolls-Royce has found the specified limits to be incorrect such that the shot peened surface layer at life critical features (the axial dovetail slots) may have been inadvertently removed in-service. Removal of the shot peened layer results in increased vulnerability of the part to tensile stresses, which could reduce the life of the shaft to below the published life limits.

We are proposing this AD to prevent failure of the intermediate-pressure (IP) and high-pressure (HP) shaft, which could result in an overspeed condition, possible uncontained disc failure and damage to the airplane.

DATES:

We must receive comments on this proposed AD by May 24, 2010.

ADDRESSES:

You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-0001.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
• Fax: [phone].

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone [phone]) is the same as the Mail address provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

James Lawrence, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: [e-mail]; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2010-0364; Directorate Identifier 2009-NE-27-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD based on those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of the Web site, anyone can find and read the comments in any of our dockets, including, if provided, the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78).

Discussion

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued EASA Airworthiness Directive 2009-0021 (Corrected February 9, 2009), dated February 6, 2009 (referred to after this as “the MCAI”), to correct an unsafe condition for the specified products. The MCAI states:

In completing a review of Engine Manual repair/acceptance limits for titanium compressor shafts, Rolls-Royce has found the specified limits to be incorrect such that the shot peened surface layer at life critical features (the axial dovetail slots) may have been inadvertently removed in-service. Removal of the shot peened layer results in increased vulnerability of the part to tensile stresses, which could reduce the life of the shaft to below the published life limits. The acceptable limits for material loss on these surfaces have now been corrected in the Engine Manual.

This AD identifies shafts for which such dressing operations have been known to have been carried out and requires that an inspection for compliance with the corrected Engine Manual limits be accomplished and that the shafts be dispositioned accordingly.

You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

Rolls-Royce plc has issued Alert Service Bulletin RB.211-72-AG086, dated December 4, 2008. The actions described in this service information are intended to correct the unsafe condition identified in the MCAI.

FAA's Determination and Requirements of This Proposed AD

This product has been approved by the aviation authority of the United Kingdom, and is approved for operation in the United States. Pursuant to our bilateral agreement with the United Kingdom, they have notified us of the unsafe condition described in the MCAI and service information referenced above. We are proposing this AD because we evaluated all information provided by EASA and determined the unsafe condition exists and is likely to exist or develop on other products of the same type design.

Costs of Compliance

Based on the service information, we estimate that this proposed AD would affect about 12 products of U.S. registry. We also estimate that it would take about 8 work-hours per product to comply with this proposed AD. The average labor rate is $85 per work-hour. Required parts would cost about $15,000 per product. Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $188,160. Our cost estimate is exclusive of possible warranty coverage.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. “Subtitle VII: Aviation Programs,” describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in “Subtitle VII, Part A, Subpart III, Section 44701: General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We 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 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. 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket.

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 FAA 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 AD:

Rolls-Royce plc: Docket No. FAA-2010-0364; Directorate Identifier 2009-NE-27-AD.

Comments Due Date

(a) We must receive comments by May 24, 2010.

Affected Airworthiness Directives (ADs)

(b) None.

Applicability

(c) This AD applies to Rolls-Royce plc model (RR) RB211 Trent 768-60, 772-60, 772B-60, 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines that have a compressor shaft listed by part number and serial number in Table 1 of this AD. These engines are installed on, but not limited to, Airbus A330 series and Boeing 777 series airplanes.

Reason

(d) This AD results from a review of engine manual repair/acceptance limits for titanium compressor shafts by RR. We are issuing this AD to prevent failure of the intermediate-pressure (IP) and high-pressure (HP) shaft, which could result in an overspeed condition, possible uncontained disc failure and damage to the airplane.

Actions and Compliance

(e) Unless already done, do the following actions.

(1) Perform a one-time, piece-part, full-focused inspection of the IP and HP compressor shafts listed by part number and serial number in Table 1 of this AD before exceeding the compliance period specified in Table 1 of this AD.

(2) Guidance on full-focused inspections and acceptance limits can be found in the current, applicable RR engine manual.

Table 1—List of Affected Shafts

Engine series	Affected component	Part No.	Shaft serial No.	Compliance period (flight cycles in service after December 4, 2008.)
Trent 800	1-8 IP Compressor Shaft	FK24100	MW0115238	750
Trent 800	1-4 HP Compressor Shaft	FK32580	MW0115512	750
Trent 800	1-4 HP Compressor Shaft	FK32580	MW0004708	2000
Trent 800	1-4 HP Compressor Shaft	FK32580	MW00063868	2500
Trent 800	1-8 IP Compressor Shaft	FK24100	DN65507	2500
Trent 800	1-8 IP Compressor Shaft	FK24100	DN65158	2500
Trent 800	1-4 HP Compressor Shaft	FK32580	MW0125467	3500
Trent 800	1-4 HP Compressor Shaft	FW11590	DN65189	3500
Trent 800	1-8 IP Compressor Shaft	FK24100	MW0091518	3500
Trent 800	1-8 IP Compressor Shaft	FK24100	MW0126365	3500
Trent 800	1-8 IP Compressor Shaft	FK24100	DN66422	4750
Trent 800	1-8 IP Compressor Shaft	FK24100	MW0203314	4750
Trent 700	1-8 IP Compressor Shaft	FK22279	DN63228	3250
Trent 700	1-8 IP Compressor Shaft	FK26048	MW0026046	4500

Other FAA AD Provisions

(f) Alternative Methods of Compliance (AMOCs): The Manager, Engine Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

Related Information

(g) Refer to MCAI EASA Airworthiness Directive 2009-0021 (Corrected 09 February, 2009), dated February 6, 2009, for related information.

(h) Contact James Lawrence, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: [e-mail]; telephone [phone]; fax [phone], for more information about this AD.

Issued in Burlington, Massachusetts, on March 31, 2010.

Peter A. White,

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