E7-18324. Airworthiness Directives; Rolls-Royce plc RB211 Trent 500 Series Turbofan Engines

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Final rule; request for comments.

SUMMARY:

We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) provided by an aviation authority of the United Kingdom (UK) to identify and correct an unsafe condition on Rolls-Royce plc RB211 Trent 500 series turbofan engines. The MCAI states the following:

This AD requires replacement of Intermediate Pressure Compressor (IP Compressor) Drums (Part Number FK30102) of nine part serial numbers. This action is necessary following the discovery of strain induced porosity in a Trent 500 IP Compressor Drum forging. Engineering assessment concluded that the problem is caused by the forging process and it is believed that this is a batch related occurrence. Nine discs, identified as coming from the same batch, could be affected by this problem. Strain induced porosity in the dovetail posts of the stage 1 of the IP Compressor drum could result, in the worst case, in an uncontained loss of 2 IP Compressor stage 1 blades. Thus, the strain induced porosity possibly affecting those nine discs presents a potential unsafe condition.

We are issuing this AD to prevent uncontained loss of IP compressor stage 1 blades.

DATES:

This AD becomes effective October 3, 2007. We must receive comments on this AD by October 3, 2007.

ADDRESSES:

You may send comments by any of the following methods:

• DOT Docket Web Site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Mail: U.S. Department of Transportation, Docket Operations, M-30, 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].
• Federal eRulemaking Portal: http://www.regulations.gov. Follow the instructions for submitting comments.

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 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 and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: [e-mail], telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

Discussion

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued AD 2007-0046, dated February 22, 2007, to correct an unsafe condition for the specified products. The EASA AD states:

This Airworthiness Directive requires replacement of Intermediate Pressure Compressor (IP Compressor) Drums (Part Number FK30102) of nine part serial numbers. This action is necessary following the discovery of strain induced porosity in a Trent 500 IP Compressor Drum forging. Engineering assessment concluded that the problem is caused by the forging process and it is believed that this is a batch related occurrence. Nine discs, identified as coming from the same batch, could be affected by this problem. Strain induced porosity in the dovetail posts of the stage 1 of the IP Compressor drum could result, in the worst case, in an uncontained loss of 2 IP Compressor stage 1 blades. Thus, the strain induced porosity possibly affecting those nine discs presents a potential unsafe condition.

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

Relevant Service Information

Rolls-Royce plc has issued Mandatory Service Bulletin No. 292 73 2818, Original Issue, dated October 18, 2006, and Update No. 1, dated April 3, 2007. 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 AD

This product has been approved by the aviation authority of the UK and is approved for operation in the United States. Pursuant to our bilateral agreement with the UK, they have notified us of the unsafe condition described in the EASA AD and service information referenced above. We are issuing this AD because we evaluated all the 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 AD requires removal of IP Compressor Drums, part number FK30102, serial numbers MW0134967, MW0131219, MW0156891, MW0158192, MW0164840, MW0168864, MW0168190, MW0171399, and KHI00012 from service at the next engine overhaul or before accumulating 2,190 cycles-since-new, whichever occurs first. This AD also requires replacement with a serviceable Drum.

FAA's Determination of the Effective Date

An unsafe condition exists that requires the immediate adoption of this AD. The FAA has found that the risk to the flying public justifies waiving notice and comment prior to adoption of this rule because no airplanes that are registered in the United States use these engines. Therefore, we determined that notice and opportunity for public comment before issuing this AD are unnecessary and that good cause exists for making this amendment effective in fewer than 30 days.

Comments Invited

This AD is a final rule that involves requirements affecting flight safety, and we did not precede it by notice and opportunity for public comment. We invite you to send any written relevant data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2007-27955; Directorate Identifier 2007-NE-15-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this AD. We will consider all comments received by the closing date and may amend this AD because of 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 AD.

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 AD will not have federalism implications under Executive Order 13132. This AD will 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 AD:

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 AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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:

2007-19-10 Rolls-Royce plc: Amendment 39-15201; Docket No. FAA-2007-27955; Directorate Identifier 2007-NE-15-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective October 3, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Rolls-Royce plc RB211 Trent 553-61, 556-61, 556B-61, 560-61, 553A2-61, 556A2-61, 556B2-61, and 560A2-61 turbofan engines. These engines are installed on, but not limited to, Airbus A340-500 and 600 series airplanes.

Reason

(d) European Aviation Safety Agency (EASA) AD No. 2007-0046, dated February 22, 2007, states:

This Airworthiness Directive requires replacement of Intermediate Pressure Compressor (IP Compressor) Drums (Part Number FK30102) of nine part serial numbers. This action is necessary following the discovery of strain induced porosity in a Trent 500 IP Compressor Drum forging. Engineering assessment concluded that the problem is caused by the forging process and it is believed that this is a batch related occurrence. Nine discs, identified as coming from the same batch, could be affected by this problem. Strain induced porosity in the dovetail posts of the stage 1 of the IP Compressor drum could result, in the worst case, in an uncontained loss of 2 IP Compressor stage 1 blades. Thus, the strain induced porosity possibly affecting those nine discs presents a potential unsafe condition.

Actions and Compliance

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

(1) Remove the IP Compressor Drums, part number FK30102, serial numbers MW0134967, MW0131219, MW0156891, MW0158192, MW0164840, MW0168864, MW0168190, MW0171399, and KHI00012, from service at the next engine overhaul or before accumulating 2,190 cycles-since-new, whichever occurs first.

(2) Replace these IP Compressor Drums with a serviceable Drum.

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 AD 2007-0046, dated February 22, 2007, and Rolls-Royce plc Alert Service Bulletin No. RB.211-72-AF258, Revision 1, dated March 29, 2007, for related information.

(h) Contact Christopher Spinney, 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 September 11, 2007.

Francis A. Favara,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.