2011-26823. Airworthiness Directives; CFM International, S. A. Model CFM56-5B 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 would require removing from service certain serial number (S/N) fan blades, part number (P/N) 338-002-114-0. This proposed AD was prompted by a normal quality sampling at CFM that isolated a production batch of fan blades with nonconforming geometry of mid-span shroud tips of the fan blades. This defect would cause the upper panel of the fan blade to be liberated following foreign object damage (FOD) or bird strike, and likely result in an inflight shutdown (IFSD). We are proposing this AD to prevent an IFSD of one or more engines following FOD or a bird strike.

DATES:

We must receive comments on this proposed AD by December 2, 2011.

ADDRESSES:

You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• 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.

For service information identified in this proposed AD, contact CFM International, Inc., Aviation Operations Center, 1 Neumann Way, M/D Room 285, Cincinnati, OH 45125; International Phone: [phone]; USA Phone: [phone]; International Fax: [phone]; USA Fax: [phone]; e-mail: [e-mail]; or CFM International SA, Customer Support Center, International Phone: [phone]; Fax: [phone]; e-mail: [e-mail].

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​; or in person at the Docket Management Facility 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 Office (phone: [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Carlos Fernandes, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; phone: [phone]; fax: [phone]; e-mail: [e-mail].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2011-0946; Directorate Identifier 2011-NE-02-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 because 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 we receive about this proposed AD.

Discussion

We received a report that CFM International conducted a normal quality sampling on fan blades, P/N 338-002-114-0, from a supplier. That quality investigation isolated a production batch of 706 blades that did not conform to the engineering drawings for the fan blades. The supplier had performed a hand-polishing operation that reduced the contact surface on adjacent blades. The reduced surface contact will likely create greater contact forces on the adjacent blades during a FOD or bird strike event. The increased forces would cause the upper panel of the fan blade to be liberated following FOD or bird strike and likely result in an IFSD.

Relevant Service Information

We reviewed CFM International Service Bulletin (SB) CFM56-5B S/B 72-0777, Revision 1, dated April 11, 2011. The SB describes procedures for replacing the suspect fan blades and contains an appendix that lists suspect fan blades, P/N 338-002-114-0, by blade S/N and known engine S/N.

FAA's Determination

We are proposing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.

Proposed AD Requirements

This proposed AD would require removing from service within 5,000 flight hours (FHs) after the effective date of this proposed AD, any fan blade, P/N 338-002-114-0, that has an S/N listed in CFM International SB CFM56-5B S/B 72-0777, Revision 1, dated April 11, 2011. After the effective date of this proposed AD, it would also prohibit installing any fan blade, P/N 338-002-114-0, that has an S/N listed in Appendix A of CFM International SB CFM56-5B S/B 72-0777, Revision 1, dated April 11, 2011.

Differences Between the Proposed AD and the Service Information

CFM International SB CFM56-5B S/B 72-0777, Revision 1, dated April 11, 2011, requires replacing suspect fan blades within 1,600 FHs on airplanes with suspected blades on both engines and within 5,000 FHs on airplanes with suspected blades on one engine. This proposed AD would require removing from service suspect blades on any engine within 5,000 FHs based on risk analysis.

Costs of Compliance

We estimate that this proposed AD would affect 16 engines installed on airplanes of U.S. registry. We also estimate that it would take about 6 work-hours per engine to perform the required actions and that the average labor rate is $85 per work-hour. Required parts would cost about $47,830 per engine. Based on these figures, we estimate the total cost of this proposed AD to U.S. operators to be $773,440.

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),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• 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 airworthiness directive (AD):

CFM International S.A.: Docket No. FAA-2011-0946; Directorate Identifier 2011-NE-02-AD.

Comments Due Date

(a) We must receive comments by December 2, 2011.

Affected ADs

(b) None.

Applicability

(c) This AD applies to CFM International, S.A. CFM56-5B1/3, CFM56-5B2/3, CFM56-5B3/3, CFM56-5B4/3, CFM56-5B5/3, CFM56-5B6/3, CFM56-5B7/3, CFM56-5B8/3, CFM56-5B9/3, CFM56-5B3/3B1, and CFM56-5B4/3B1 engines equipped with fan blades P/N 338-002-114-0 that have a serial number (S/N) listed in Appendix A of CFM International Service Bulletin (SB) CFM56-5B S/B 72-0777, Revision 1, dated April 11, 2011.

Unsafe Condition

(d) This AD was prompted by a normal quality sampling at CFM that isolated a production batch of fan blades with nonconforming geometry of mid-span shroud tips of the fan blades. This defect would cause the upper panel of the fan blade to be liberated following foreign object damage (FOD) or a bird strike and likely result in an inflight shutdown (IFSD). We are proposing this AD to prevent an IFSD of one or more engines following FOD or a bird strike.

Compliance

(e) Comply with this AD within the compliance times specified, unless already done.

Remove Fan Blades From Service

(f) For engines that have fan blades, P/N 338-002-114-0 with S/Ns listed in Appendix A of CFM International SB CFM56-5B S/B 72-0777, Revision 1, dated April 11, 2011, remove the fan blade from service within 5,000 flight hours after the effective date of this AD.

Installation Prohibition

(g) After the effective date of this AD, do not install any fan blade, P/N 338-002-114-0 that has an S/N listed in Appendix A of CFM International SB CFM56-5B S/B 72-0777, Revision 1, dated April 11, 2011, onto any engine.

Alternative Methods of Compliance (AMOCs)

(h) 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

(i) For more information about this AD, contact Carlos Fernandes, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; phone: [phone]; fax: [phone]; e-mail: [e-mail].

(j) For service information identified in this AD, contact CFM International, Inc., Aviation Operations Center, 1 Neumann Way, M/D Room 285, Cincinnati, OH 45125; International Phone: [phone]; USA Phone: [phone]; International Fax: [phone]; USA Fax: [phone]; e-mail: [e-mail]; or CFM International SA, Customer Support Center, International Phone: [phone]; Fax: [phone]; e-mail: [e-mail]. You may review copies of the referenced service information at the FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA, 01803. For information on the availability of this material at the FAA, call 781-238-7125.

Issued in Burlington, Massachusetts on October 6, 2011.

Peter A. White,

Manager, Engine & Propeller Directorate, Aircraft Certification Service.