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Proposed Rule

Airworthiness Directives; CFM International, S.A. Models CFM56-3 and -3B Turbofan Engines

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

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AGENCY:

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

ACTION:

Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.

SUMMARY:

This supplemental NPRM revises an earlier proposed airworthiness directive (AD), for certain CFM International, S.A. models CFM56-3 and -3B turbofan engines. That proposed AD would have required initial and repetitive inspections for damage to the fan blades. That proposed AD resulted from a report of a failed fan blade with severe out-of-limit wear on the underside of the blade platform where it contacts the damper. This supplemental NPRM revises the proposed AD to reduce the initial inspection compliance threshold, to correct the engine model designations affected, and to clarify some of the inspection wording in the compliance section. This supplemental NPRM results from a report of a failed fan blade with severe out-of-limit wear on the underside of the blade platform where it contacts the damper. We are proposing this supplemental NPRM to prevent failure of multiple fan blades, which could result in an uncontained failure of the engine and damage to the airplane.

DATES:

We must receive any comments on this supplemental NPRM by May 17, 2010.

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: (202) 493-2251.

You can get the service information identified in this proposed AD from CFM International, S. A., Technical Publication Department, 1 Neumann Way, Cincinnati, OH 45215; telephone (513) 552-2800; fax (513) 552-2816.

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FOR FURTHER INFORMATION CONTACT:

Antonio Cancelliere, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: antonio.cancelliere@faa.gov; telephone (781) 238-7751; fax (781) 238-7199.

End Further Info End Preamble Start Supplemental Information

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-2009-0606; Directorate Identifier 2009-NE-11-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 Start Printed Page 16362Register 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 (800) 647-5527) is the same as the Mail address provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

Discussion

On July 16, 2009, we proposed to amend part 39 of the Code of Federal Regulations (14 CFR part 39) to add an AD for CFM International, S.A. models CFM56-3B1 and-3B2 turbofan engines. That action proposed to require initial and repetitive fan blade inspections. That proposed AD resulted from a report of a failed fan blade with severe out-of-limit wear on the underside of the blade platform where it contacts the damper.

Since we issued the proposed AD, we discovered that we need to make some changes to reduce the initial inspection compliance threshold, to correct the engine model designations affected, and to clarify some of the inspection wording in the compliance section of the proposed AD.

Comments

We provided the public the opportunity to participate in the development of that proposed AD. We have considered the comments received.

Request to Correct the Engine Model Designations Affected

One commenter, CFM International, S.A., requests that we correct the engine model designations affected. The commenter states that the proposed AD models of CFM56-3B1 and -3B2 are incorrect and should be changed to CFM56-3-B1 and -3B-2.

We partially agree. We agree that we listed incorrect model designations. We corrected them in this supplemental NPRM to agree with the CFM56 Type Certificate Data Sheet E2GL title block, which lists the affected models as CFM56-3 and -3B. We do not agree that the model designations should be solely listed as CFM56-3-B1 and -3B-2. However, because CFM International, S.A. has added to the basic engine model number on the engine nameplate to identify minor variations in engine configuration, installation components, or reduced ratings peculiar to aircraft installation requirements, engine models CFM56-3-B1 and CFM56-3B-2 are also affected by this proposed AD.

Request To Add an Installation Prohibition

CFM International, S.A. requests that we add an installation prohibition to our proposed AD applicability, that the installation of 25 degrees midspan shroud fan blades is not allowed on the CFM56-3C engine model.

We do not agree. The applicability is clear that the proposed AD does not include the -3C engine model, as it does not list that model. We did not change the NPRM.

Request To Change the Initial Inspection Threshold

CFM International, S.A. requests that we change the initial inspection threshold from 3,000 cycles-in-service (CIS) to within 3 to 6 months of AD issuance to better harmonize our compliance with European Aviation Safety Agency AD 2009-036 (3 months) or with CFM International, S.A. CFM56-3/3B/3C S/B 72-1067, dated February 15, 2007 (6 months).

We do not agree that a 3 to 6 month interval is appropriate, as the passage of time without service is unrelated to the progression of the unsafe condition. We do agree that the initial inspection threshold of 3,000 CIS is too long. We reduced the initial inspection threshold to 900 CIS in the NPRM.

Differences Between the Supplemental NPRM and the Manufacturer's Service Information

CFM International Service Bulletin (SB) No. CFM56-3/3B/3C S/B 72-1067, dated February 15, 2007, requires an initial inspection within 6 months. This supplemental NPRM would require the initial inspection within 900 CIS after the effective date of the supplemental NPRM. CFM International SB No. CFM56-3/3B/3C S/B 72-1067, dated February 15, 2007, also requires a repetitive inspection within 1,500 to 3,000 cycles-since-last inspection (CSLI). This supplemental NPRM would require the repetitive inspection within 3,000 CSLI.

FAA's Determination and Requirements of the Supplemental NPRM

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 performing initial and repetitive inspections of the fan blade for wear. The supplemental NPRM would require you to use the service information described previously to perform these actions.

Costs of Compliance

We estimate that this supplemental NPRM would affect 50 engines installed on airplanes of U.S. registry. We also estimate that it would take about 8 work-hours per engine to perform the proposed actions, and that the average labor rate is $80 per work-hour. Required parts would cost about $38,000 per engine. Based on these figures, we estimate the total cost of the supplemental NPRM to U.S. operators to be $1,932,000.

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 supplemental NPRM would not have federalism implications under Executive Order 13132. This supplemental NPRM 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 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. 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.Start Printed Page 16363

We prepared a regulatory evaluation of the estimated costs to comply with this supplemental NPRM. See the ADDRESSES section for a location to examine the regulatory evaluation.

Start List of Subjects

List of Subjects in 14 CFR Part 39

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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:

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PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive:

CFM International, S.A.: Docket No. FAA-2009-0606; Directorate Identifier 2009-NE-11-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by May 17, 2010.

Affected ADs

(b) None.

Applicability

(c) This AD applies to CFM International, S.A. models CFM56-3 and -3B turbofan engines with 25 degrees midspan shroud fan blades, part numbers (P/Ns) 9527M99P08, 9527M99P09, 9527M99P10, 9527M99P11, 1285M39P01, or fan blade pairs, P/Ns 335-088-901-0, 335-088-902-0, 335-088-903-0, and 335-088-904-0 installed. These engines are installed on, but not limited to, Boeing 737 series airplanes.

(d) CFM International, S.A. has added to the basic engine model number on the engine nameplate to identify minor variations in engine configuration, installation components, or reduced ratings peculiar to aircraft installation requirements.

(e) Those engines marked on the engine data plate as CFM56-3-B1 are included in this AD as CFM56-3 turbofan engines.

(f) Those engines marked on the engine data plate as CFM56-3B-2 are included in this AD as CFM56-3B turbofan engines.

Unsafe Condition

(g) This AD results from a report of a failed fan blade with severe out-of-limit wear on the underside of the blade platform where it contacts the damper. We are issuing this AD to prevent failure of multiple fan blades, which could result in an uncontained failure of the engine and damage to the airplane.

Compliance

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

Inspection for Wear

(i) Within 900 cycles-in-service after the effective date of this AD, perform an on-wing or in-shop inspection of the fan blade and damper for wear. Use paragraphs 3.A.(1) through 3.A.(5) or paragraphs 3.B.(1) through 3.B.(5) respectively, of the Accomplishment Instructions of CFM International Service Bulletin (SB) No. CFM56-3/3B/3C S/B 72-1067, dated February 15, 2007.

(j) If you find out-of-limit wear on at least one fan blade platform underside, perform the additional inspections and disposition the parts, as specified in paragraphs 3.A.(3) and 3.A.(5) or paragraphs 3.B.(3) and 3.B.(5) respectively, of the Accomplishment Instructions of CFM International SB No. CFM56-3/3B/3C S/B 72-1067, dated February 15, 2007.

(k) Thereafter, within intervals not to exceed 3,000 cycles-since-last inspection, perform an on-wing or in-shop inspection for wear. Use paragraphs 3.A.(1) through 3.A.(5) or paragraphs 3.B.(1) through 3.B.(5) respectively, of the Accomplishment Instructions of CFM International SB No. CFM56-3/3B/3C S/B 72-1067, dated February 15, 2007.

(l) If you find wear on at least one fan blade platform underside, perform additional inspections and disposition the parts, as specified in paragraphs 3.A.(3) and 3.A.(5) or paragraphs 3.B.(3) and 3.B.(5) respectively, of the Accomplishment Instructions of CFM International SB No. CFM56-3/3B/3C S/B 72-1067, dated February 15, 2007.

Installation Prohibition

(m) After the effective date of this AD, don't install any 25 degrees midspan shroud fan blades, P/Ns 9527M99P08, 9527M99P09, 9527M99P10, 9527M99P11, 1285M39P01, or fan blade pairs, P/Ns 335-088-901-0, 335-088-902-0, 335-088-903-0, and 335-088-904-0, unless they have passed an inspection specified in paragraph 3. of the Accomplishment Instructions of CFM International SB No. CFM56-3/3B/3C S/B 72-1067, dated February 15, 2007.

Optional Terminating Action

(n) Replacing the 25 degrees midspan shroud fan blade set with a 37 degrees midspan shroud fan blade set terminates the repetitive inspection requirements specified in paragraph (k) of this AD.

Alternative Methods of Compliance

(o) 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

(p) Contact Antonio Cancelliere, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: antonio.cancelliere@faa.gov; telephone (781) 238-7751; fax (781) 238-7199, for more information about this AD.

(q) Contact CFM International, S.A., Technical Publication Department, 1 Neumann Way, Cincinnati, OH 45215; telephone (513) 552-2800; fax (513) 552-2816, for a copy of the service information referenced in this AD.

(r) European Aviation Safety Agency AD 2009-0036, dated February 20, 2009, also addresses the subject of this AD.

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Issued in Burlington, Massachusetts, on March 19, 2010.

Peter A. White,

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

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[FR Doc. 2010-7343 Filed 3-31-10; 8:45 am]

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