E7-20242. Airworthiness Directives; Rolls-Royce plc (RR) RB211 Trent 500, 700, and 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) provided by the aviation authority of the United Kingdom to identify and correct an unsafe condition on an aviation product. The MCAI states the following:

This action is necessary following the discovery of IP Compressor Rotor rear balance land cracking on an in-service Trent 800 engine. Stress analysis of the damaged rotor has shown a possible threat to the rotor integrity, the cracking therefore presents a potential unsafe condition.

We are proposing this AD to detect cracking on the intermediate pressure (IP) Compressor rotor rear balance land. IP compressor rotor rear balance land cracking can lead to uncontained failure of the rotor and damage to the airplane.

DATES:

We must receive comments on this proposed AD by November 14, 2007.

ADDRESSES:

You may send comments by any of the following methods:

• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: U.S. Department of Transportation, Docket Operations, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• 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://dms.dot.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:

Christopher Spinney, Aerospace Engineer, Engine Certification Office, FAA, Engine & 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-2007-28059; Directorate Identifier 2007-NE-13-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://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

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 2007-0052, dated February 23, 2007 to correct an unsafe condition for the specified products. The EASA AD states:

This Airworthiness Directive requires inspections for cracks in the rear balance land of the IP Compressor Rotor. The inspections comprise an on-wing one-off inspection by borescope for RR Trent 800 engines which must be completed within a short timescale, and in-shop inspections to be completed at each opportunity for RR Trent 500, 700 and 800 engines (the in-shop inspection may be carried out in lieu of the on-wing inspection for the Trent 800 engines if it is accomplished within the timescale applicable to the on-wing inspection). This action is necessary following the discovery of IP Compressor Rotor rear balance land cracking on an in-service Trent 800 engine. Stress analysis of the damaged rotor has shown a possible threat to the rotor integrity, the cracking therefore presents a potential unsafe condition. The cause of the cracking is currently not fully understood but evidence suggests it relates to an unusual balance weight condition.

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

Relevant Service Information

RR has issued Alert Service Bulletin (ASB) RB.211-72-AF313, dated February 22, 2007 and ASB RB.211-72-AF260, Revision 1, dated January 17, 2007. The actions described in this service information are intended to correct the unsafe condition identified in the EASA AD.

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 EASA AD 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. This proposed AD would require inspecting the IP Compressor rotor rear balance land for cracks.

Costs of Compliance

We estimate that this proposed AD would affect about 110 engines installed on airplanes of U.S. registry. We also estimate that it would take about 3.5 work-hours per engine to perform the proposed actions and that the average labor rate is $80 per work-hour. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $30,800. 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-2007-28059; Directorate Identifier 2007-NE-13-AD.

Comments Due Date

(a) We must receive comments by November 14, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Rolls-Royce plc RB211 Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 560-61, 560A2-61, 768-60, 772-60, 772B-60, 772C-60, 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines. These engines are installed on, but not limited to, Airbus A330, A340-500, A340-600, and Boeing 777 series airplanes.

Reason

(d) This action is necessary following the discovery of IP Compressor Rotor rear balance land cracking on an in-service Trent 800 engine. Stress analysis of the damaged rotor has shown a possible threat to the rotor integrity, the cracking therefore presents a potential unsafe condition. The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.

We are proposing this AD to detect cracking on the intermediate pressure (IP) Compressor rotor rear balance land. IP compressor rotor rear balance land cracking can lead to uncontained failure of the rotor and damage to the airplane.

Actions and Compliance

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

Inspection—On-Wing

(1) Applicable to RR Trent 800 engines not previously inspected per Rolls-Royce RB211 Propulsion System Alert Non Modification Service Bulletin RB.211-72-AF260, Revision 1, dated January 17, 2007 or original issue, dated October17, 2006: Within 400 flight cycles of the Effective Date of this AD inspect the IP Compressor rotor rear balance land for cracks in accordance with Rolls-Royce RB211 Propulsion System Alert Non Modification Service Bulletin RB.211-72-AF313, dated February 22, 2007 section 3 Accomplishment Instructions. Engines on which cracking is found should be rejected from service.

Inspection—In-Shop

(2) Applicable to RR Trent 500, 700 and 800 engines at each shop visit in which the engine is sufficiently disassembled to access the IP Compressor Module rear face: Inspect the IP Compressor rotor rear balance land for cracks in accordance with Rolls-Royce RB211 Propulsion System Alert Non Modification Service Bulletin RB.211-72-AF260, Revision 1, dated January 17, 2007, or original issue section 3 Accomplishment Instructions.

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 EASA Airworthiness Directive 2007-0052, dated February 23, 2007, and Rolls-Royce plc Alert Service Bulletin (ASB) RB.211-72-AF313, dated February 22, 2007, and ASB RB.211-72-AF260, Revision 1, dated January 17, 2007, for related information.

(h) Contact Christopher Spinney, Aerospace Engineer, Engine Certification Office, FAA, Engine & 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 October 9, 2007.

Peter A. White,

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