E8-13056. Airworthiness Directives; Rolls-Royce Corporation AE 3007A1E and AE 1107C Turbofan/Turboshaft Engines

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for Rolls-Royce Corporation (RRC) AE 3007A1E and AE 1107C turbofan/turboshaft engines. This proposed AD would require removal from service of certain 2nd stage, 3rd stage, and 4th stage compressor wheels, compressor cone shaft assemblies, and 1st to 2nd-stage turbine spacers, at new, reduced, published life limits. This proposed AD results from RRC applying an updated lifing methodology to the affected parts. We are proposing this AD to prevent low-cycle-fatigue (LCF) failure of the parts listed in Table 1 of this proposed AD, which could result in an uncontained engine failure and damage to the aircraft.

DATES:

We must receive any comments on this proposed AD by August 11, 2008.

ADDRESSES:

Use one of the following addresses to comment on this proposed AD.

• 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].

You can get the service information identified in this proposed AD from Rolls-Royce Corporation, P.O. Box 420, Indianapolis, IN 46206; e-mail: [e-mail]; telephone [phone]; fax [phone].

FOR FURTHER INFORMATION CONTACT:

Michael Downs, Aerospace Engineer, Chicago Aircraft Certification Office, Small Airplane Directorate, FAA, 2300 E. Devon Ave., Des Plaines, IL 60018; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send us any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2008-0230; Directorate Identifier 2007-NE-24-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of 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).

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.

Discussion

RRC was seeking to increase the LCF lives of the compressor wheels used in AE 3007A1E and AE 1107C turbofan/turboshaft engines, by applying an updated lifing methodology. However, their engine testing and evaluation revealed that some of the compressor wheels experienced crack initiation in the dovetail slots. RRC found that these parts were likely to fail within their published lives, and that that failure presented an unacceptable compromise to safety. As a result, RRC decreased the published life limits of the compressor wheels, and also recalculated and decreased the published life of certain compressor cone shaft assemblies and 1st-to-2nd stage turbine spacers. We reviewed RRC's testing results and reached the same conclusion. These conditions, if not corrected, could lead to LCF failure of the parts listed in Table 1 of this proposed AD, which could result in an uncontained engine failure and damage to the aircraft.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other products of this same type design. We are proposing this AD, which would require removal from service of the parts listed in Table 1 of this proposed AD, at new, reduced, published life limits.

Costs of Compliance

We estimate that this proposed AD would affect 220 AE 3007A1E turbofan engines installed on aircraft of U.S. registry. The proposed action does not impose any additional labor costs since it will be performed at engine overhaul. Required parts would cost about $100,000 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $22,000,000.

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 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 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. 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 regulatory evaluation of the estimated costs to comply with this proposed AD. You may get a copy of this summary at the address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

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 Corporation (Formerly Allison Engine Company, Inc.): Docket No. FAA-2008-0230; Directorate Identifier 2007-NE-24-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by August 11, 2008.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Rolls-Royce Corporation (RRC) AE 3007A1E and AE 1107C turbofan/turboshaft engines, with the following parts in Table 1 installed, as applicable:

Table 1.—Affected Parts and Reduced Life Limits

Engine	Part name	Part No.	New reduced published life limit, in flight cycles
AE 3007A1E	2nd Stage Compressor Wheel	23050752	15,200
	3rd Stage Compressor Wheel	23065303	13,300
AE 1107C	2nd Stage Compressor Wheel	23050752	11,400
	2nd Stage Compressor Wheel	23084157	11,400
	3rd Stage Compressor Wheel	23065303	6,200
	3rd Stage Compressor Wheel (serial numbers L72422, L72475, L72505, L130704, L130829, L130830, L138218, L138226, L138621, L206084, L206163)	23065303	5,000
	3rd Stage Compressor Wheel	23084158	6,200
	4th Stage Compressor Wheel	23050754	14,900
	4th Stage Compressor Wheel	23071259	14,900
	4th Stage Compressor Wheel	23084159	14,900
	Compressor Cone Shaft Assembly	23050728	2,900
	Compressor Cone Shaft Assembly	23070729	2,900
	1st to 2nd-Stage Turbine Spacer	23065300	9,500

AE 3007A1E turbofan engines are installed on, but not limited to, EMBRAER EMB-135BJ and EMB-145XR airplanes. AE 1107C turboshaft engines are U.S. type-certificated and are installed on, but not limited to, certain U.S. military aircraft.

Unsafe Condition

(d) This AD results from RRC applying an updated lifing methodology to the affected parts. We are issuing this AD to prevent low-cycle-fatigue failure of the parts listed in Table 1 of this AD, which could result in an uncontained engine failure and damage to the aircraft.

Compliance

(e) You are responsible for having the actions required by this AD performed within 5 days after the effective date of this AD, unless the actions have already been done.

(f) Remove from service the parts listed in Table 1 of this AD, at the new, reduced, published life limits specified in Table 1 of this AD.

Alternative Methods of Compliance

(g) The Manager, Chicago Aircraft Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19.

Related Information

(h) RRC Alert Service Bulletin (ASB) No. AE 3007A-A-72-346, dated May 1, 2007; Service Bulletin No. AE 1107C-A-72-086, Revision 2, dated January 28, 2008; and ASB No. AE 1107C-A-72-089, dated January 28, 2008, also pertain to the subject of this AD.

(i) Contact Michael Downs, Aerospace Engineer, Chicago Aircraft Certification Office, Small Airplane Directorate, FAA, 2300 E. Devon Ave., Des Plaines, IL 60018; telephone [phone]; fax [phone], for more information about this AD.

Issued in Burlington, Massachusetts, on June 5, 2008.

Robert G. Mann,

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