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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. FAA-2008-0174; Directorate Identifier 2008-NE-03-AD] 
          - RIN 2120-AA64 

# 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 CFM International, S.A. CFM56-5B1/P; -5B2/P; -5B3/P; -5B3/P1; -5B4/P; -5B4/P1; -5B5/P; -5B6/P; -5B7/P; -5B8/P; and -5B9/P 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 lifing analysis by the engine manufacturer that shows the need to identify initial and repetitive inspection thresholds for inspecting certain LP turbine rear frames. We are proposing this AD to detect low-cycle-fatigue cracks in the LP turbine rear frame, which 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 7, 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:                          (202) 493-2251.                     

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

# FOR FURTHER INFORMATION CONTACT:

                        Stephen Sheely, Aerospace Engineer,                               ( print page 25598)                            Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail:                         *stephen.k.sheely@faa.gov;*                         telephone (781) 238-7750; fax (781) 238-7199.                     

# 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-2008-0174; Directorate Identifier 2008-NE-03-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 (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 

CFM International, S.A. performed a refined lifing analysis that shows the need to identify initial and repetitive inspection thresholds for inspecting LP turbine rear frames, P/Ns 338-171-703-0; 338-171-704-0; 338-171-705-0; and 338-171-706-0. These parts are installed in CFM56-5B1/P; -5B2/P; -5B3/P; -5B3/P1; -5B4/P; -5B4/P1; -5B5/P; -5B6/P; -5B7/P; -5B8/P; and -5B9/P 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 low-cycle-fatigue cracks in the LP turbine rear frame, 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 No. CFM56-5B S/B 72-0620, Revision 1, dated December 20, 2007, that describes procedures for performing 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. 

## Costs of Compliance 

We estimate that this proposed AD would affect 426 CFM56-5B 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 $102,240. If all 426 LP turbine rear frames needed replacement, we estimate the total cost of the proposed AD to U.S. operators to be $43,656,480. 

## 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 

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

**CFM International, S.A.:**                                 Docket No. FAA-2008-0174; Directorate Identifier 2008-NE-03-AD.                             

## Comments Due Date 

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by July 7, 2008. 

## Affected ADs 

(b) None. 

## Applicability 

                                (c) This AD applies to CFM International, S.A. CFM56-5B1/P; -5B2/P; -5B3/P; -5B3/P1; -5B4/P; -5B4/P1; -5B5/P; -5B6/P; -5B7/P; -5B8/P; and -5B9/P turbofan engines with                                       ( print page 25599)                                    low-pressure (LP) turbine rear frames, part numbers 338-171-703-0; 338-171-704-0; 338-171-705-0; and 338-171-706-0, installed. These engines are installed on, but not limited to, Airbus A318, A319, A320, and A321 series airplanes.                             

## Unsafe Condition 

(d) This AD results from a refined lifing analysis by the engine manufacturer that shows the need to identify initial and repetitive inspection thresholds for inspecting certain LP turbine rear frames. We are issuing this AD to detect low-cycle-fatigue cracks in the LP turbine rear frame, which 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. 

## Initial Inspection 

(f) Perform an initial eddy current inspection (ECI) of the LP turbine rear frame using paragraphs 3.A. through 3.A.(7)(d) of the Accomplishment Instructions of CFM International, S.A. Service Bulletin (SB) No. CFM56-5B S/B 72-0620, Revision 1, dated December 20, 2007, at the following compliance times: 

(1) For commercial engine applications, within 25,000 cycles-since-new (CSN) on the LP turbine rear frame. 

(2) For corporate engine applications, within 19,000 CSN on the LP turbine rear frame. 

(3) For engines with unknown LP turbine rear frame CSN, within 300 cycles from the effective date of this AD. 

## Repetitive Inspections 

(g) Perform repetitive ECIs of the LP turbine rear frame using paragraphs 3.A. through 3.A.(7)(d) of the Accomplishment Instructions of CFM International, S.A. SB No. CFM56-5B S/B 72-0620, Revision 1, dated December 20, 2007. Use the inspection intervals in paragraph 3.A.(8) of the Accomplishment Instructions of CFM International, S.A. SB No. CFM56-5B S/B 72-0620, Revision 1, dated December 20, 2007. 

## LP Turbine Rear Frame Removal Criteria 

(h) Remove LP turbine rear frames from service that have a single crack length of 2.56 inches (65 mm) or longer, or multiple cracks with accumulated crack length of 2.56 inches (65 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 2007-0221, dated August 13, 2007, also addresses the subject of this AD. 

                                (k) Contact Stephen Sheely, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail:                                 *stephen.k.sheely@faa.gov;*                                 telephone (781) 238-7750; fax (781) 238-7199, for more information about this AD.                            

Issued in Burlington, Massachusetts, on April 29, 2008. 

Peter A. White, 

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

 [FR Doc. E8-10050 Filed 5-6-08; 8:45 am] 

BILLING CODE 4910-13-P