E9-10956. Airworthiness Directives; CFM International, S.A. CFM56-7B 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 CFM International, S.A. CFM56-7B series turbofan engines. This proposed AD would require initial and repetitive eddy current inspections (ECIs) of certain part number (P/N) low-pressure (LP) turbine rear frames. This proposed AD results from a refined life analysis by the engine manufacturer that shows the need to identify an initial and repetitive inspection threshold for inspecting certain LP turbine rear frames. We are proposing this AD to prevent failure of the LP turbine rear frame from low-cycle-fatigue cracks. Failure of the LP turbine rear frame could result in engine separation from the airplane, possibly leading to loss of control of the airplane.

DATES:

We must receive any comments on this proposed AD by July 10, 2009.

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].

FOR FURTHER INFORMATION CONTACT:

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

Contact CFM International, Technical Publications Department, 1 Neumann Way, Cincinnati, OH 45215; telephone [phone]; fax [phone], for a copy of the service information identified in this proposed AD.

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-2009-0236; Directorate Identifier 2009-NE-06-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

CFM International, S.A. performed a refined life analysis that identified the need for initial and repetitive inspection thresholds for LP turbine rear frames, P/Ns 340-166-254-0; 340-166-255-0; 340-166-256-0; 340-166-257-0; 340-166-258-0; 340-166-259-0; P/N 340-177-551-0; 340-177-552-0; 340-177-553-0; 340-177-554-0; 340-177-555-0; and 340-177-556-0. These LP turbine rear frames are installed on CFM56-7B series turbofan engines. This proposed AD would require initial and repetitive ECIs of these LP turbine rear frames. This condition, if not corrected, could result in engine separation from the airplane, possibly leading to loss of control of the airplane.

Relevant Service Information

We have reviewed and approved the technical contents of CFM International, S.A. Service Bulletin (SB) No. CFM56-7B S/B 72-0558, Revision 2, dated December 1, 2008, and SB No. CFM56-7B S/B 72-0579, Revision 4, dated December 1, 2008, that describe procedures for performing initial and repetitive ECIs of the LP turbine rear frame.

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 initial and repetitive ECIs of the affected P/N LP turbine rear frames. The proposed AD would require you to use the service information described previously to perform these actions.

Costs of Compliance

We estimate that this proposed AD would affect 1,228 CFM56-7B series turbofan engines installed on airplanes of U.S. registry. We estimate that it would take about 3 work-hours to perform an eddy current inspection of an LP turbine rear frame. The average labor rate is $80 per work-hour. A replacement LP turbine rear frame costs about $275,000. If all 1,228 LP turbine rear frames needed replacement, we estimate the total cost of the proposed AD to U.S. operators to be $33,994,720.

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
• Incorporation by reference
• 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:

CFM International, S.A: Docket No. FAA-2009-0236; Directorate Identifier 2009-NE-06-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by July 10, 2009.

Affected ADs

(b) None.

Applicability

(c) This AD applies to:

(1) CFM International, S.A. CFM56-7B20; -7B22; -7B24; -7B26; -7B27; -7B22/B1; -7B24/B1; -7B27/B1; -7B26/B1; -7B26/B2; -7B20/3; -7B22/3; -7B24/3; -7B26/3; -7B27/3; -7B22/3B1; -7B24/3B1; -7B27/3B1; -7B26/3B1; -7B26/3B2; -7B26/3F; -7B27/3; -7B27/3F; -7B26/3B2F; -7B27/3B1F; -7B27/3B3; and -7B27A turbofan engines assembled with a low-pressure (LP) turbine rear frame, part number (P/N) 340-166-254-0; 340-166-254-0; 340-166-255-0; 340-166-256-0; 340-166-257-0; 340-166-258-0; or 340-166-259-0; and

(2) CFM International, S.A. CFM56-7B20/2; -7B22/2; -7B24/2; -7B26/2; and -7B27/2 turbofan engines assembled with a dual annular combustor and an LP turbine rear frame, P/N 340-177-551-0; 340-177-552-0; 340-177-553-0; 340-177-554-0; 340-177-555-0; or 340-177-556-0.

(3) These engines are installed on, but not limited to, Boeing 737-600, 737-700, 737-800, and 737-900 series airplanes.

Unsafe Condition

(d) This AD results from a refined life analysis by the engine manufacturer that shows the need to identify an initial and repetitive inspection threshold for inspecting certain LP turbine rear frames. We are issuing this AD to prevent failure of the LP turbine rear frame from low-cycle-fatigue cracks. Failure of the LP turbine rear frame could result in engine separation from the airplane, possibly leading to loss of control of the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.

Inspections of LP Turbine Rear Frames

(f) For CFM International, S.A. CFM56-7B20; -7B22; -7B24; -7B26; -7B27; -7B22/B1; -7B24/B1; -7B27/B1; -7B26/B2; -7B20/3; -7B22/3; -7B24/3; -7B26/3; -7B27/3; -7B22/3B1; -7B24/3B1; -7B27/3B1; -7B26/3B2; -7B26/3F; -7B27/3F; -7B26/3B2F; -7B27/3B1F; and -7B27A turbofan engines with an LP turbine rear frame, P/N 340-166-254-0; 340-166-254-0; 340-166-255-0; 340-166-256-0; 340-166-257-0; 340-166-258-0; or 340-166-259-0, do the following:

(1) Perform an initial eddy current inspection (ECI) of the LP turbine rear frame within 25,000 cycles-since-new (CSN) on the LP turbine rear frame.

(2) For engines with unknown LP turbine rear frame CSN, perform an initial ECI within 300 cycles from the effective date of this AD.

(3) Perform repetitive ECIs of the LP turbine rear frame, using the inspection intervals in paragraph 3.A.(8) of the Accomplishment Instructions of CFM International, S.A. SB No. CFM56-7B S/B 72-0579, Revision 4, dated December 1, 2008.

(4) Use paragraphs 3.A. through 3.A.(7)(d) of the Accomplishment Instructions of CFM International, S.A. Service Bulletin (SB) No. CFM56-7B S/B 72-0579, Revision 4, dated December 1, 2008, to do the ECIs.

(5) Remove LP turbine rear frames from service that have a total cumulated crack length at any location, of 0.79 inch (20 mm) or longer.

(g) For CFM International, S.A. CFM56-7B26/B1; -7B27/3; -7B26/3B1; and -7B27/3B3 turbofan engines with an LP turbine rear frame, P/N 340-166-254-0; 340-166-254-0; 340-166-255-0; 340-166-256-0; 340-166-257-0; 340-166-258-0; or 340-166-259-0, do the following:

(1) Perform an initial ECI of the LP turbine rear frame within 19,000 CSN on the LP turbine rear frame.

(2) For engines with unknown LP turbine rear frame CSN, perform an initial ECI within 300 cycles from the effective date of this AD.

(3) Perform repetitive ECIs of the LP turbine rear frame, using the inspection intervals in paragraph 3.A.(9) of the Accomplishment Instructions of CFM International, S.A. SB No. CFM56-7B S/B 72-0579, Revision 4, dated December 1, 2008.

(4) Use paragraphs 3.A. through 3.A.(7)(d) of the Accomplishment Instructions of CFM International, S.A. Service Bulletin (SB) No. CFM56-7B S/B 72-0579, Revision 4, dated December 1, 2008, to do the ECIs.

(5) Remove LP turbine rear frames from service that have a total cumulated crack length at any location, of 0.79 inch (20 mm) or longer.

(h) For CFM International, S.A. CFM56-7B20/2; -7B22/2; -7B24/2; -7B26/2; and -7B27/2 turbofan engines assembled with a dual annular combustor and an LP turbine rear frame, P/N 340-177-551-0; 340-177-552-0; 340-177-553-0; 340-177-554-0; 340-177-555-0; or 340-177-556-0, do the following:

(1) Perform an initial ECI of the LP turbine rear frame within 16,350 CSN on the LP turbine rear frame.

(2) For engines with unknown LP turbine rear frame CSN, perform an initial ECI within 300 cycles from the effective date of this AD.

(3) Perform repetitive ECIs of the LP turbine rear frame, using the inspection intervals in paragraph 3.A.(8) of the Accomplishment Instructions of CFM International, S.A. SB No. CFM56-7B S/B 72-0558, Revision 2, dated December 1, 2008.

(4) Use paragraphs 3.A. through 3.A.(7)(d) of the Accomplishment Instructions of CFM International, S.A. SB No. CFM56-7B S/B 72-0558, Revision 2, dated December 1, 2008, to do the ECIs.

(5) Remove LP turbine rear frames from service that have a total cumulated crack length at any location, of 0.43 inch (11 mm) or longer.

Alternative Methods of Compliance

(i) The Manager, Engine 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

(j) European Aviation Safety Agency AD 2009-0009, dated January 15, 2009, also addresses the subject of this AD.

(k) Contact CFM International, Technical Publications Department, 1 Neumann Way, Cincinnati, OH 45215; telephone [phone]; fax [phone], for a copy of the service information identified in this AD.

(l) Contact Antonio Cancelliere, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: [e-mail]; 238-7751; fax [phone], for more information about this AD.

Issued in Burlington, Massachusetts, on May 4, 2009.

Peter A. White,

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