Airworthiness directives: CFM International,

[Federal Register: March 22, 1999 (Volume 64, Number 54)]

[Rules and Regulations]

[Page 13667-13669]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr22mr99-3]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-56-AD; Amendment 39-11079; AD 99-06-16]

RIN 2120-AA64

Airworthiness Directives; CFM International CFM56-5 Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment adopts a new airworthiness directive (AD), applicable to CFM International CFM56-5 series turbofan engines, that reduces the low cycle fatigue (LCF) retirement lives for certain high pressure turbine rotor (HPTR) front air seals, and provides a drawdown schedule for those affected parts with reduced LCF retirement lives. This amendment is prompted by results of a refined life analysis performed by the manufacturer that revealed minimum calculated LCF lives significantly lower than the published LCF retirement lives. The actions specified by this AD are intended to prevent a LCF failure of the HPTR front air seal, which could result in an uncontained engine failure and damage to the aircraft.

DATES: Effective April 21, 1999.

The incorporation by reference of certain publications listed in the regulations is approved by the Director

[[Page 13668]]

of the Federal Register as of April 21, 1999.

ADDRESSES: The service information referenced in this AD may be obtained from CFM International, Technical Publications Department, 1 Neumann Way, Cincinnati, OH 45215; telephone (513) 552-2981, fax (513) 552-2816. This information may be examined at the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Robert Ganley, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-7138; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to CFM International CFM56-5 series turbofan engines was published in the Federal Register on September 18, 1998 (63 FR 49879). That action proposed to require reducing the low cycle fatigue (LCF) retirement lives for certain high pressure turbine rotor (HPTR) front air seals, and provide a drawdown schedule for those affected parts with reduced LCF retirement lives in accordance with CFM International CFM56-5 Service Bulletin No. 72-541, dated July 27, 1998.

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

One commenter states that the total cost impact of the proposed AD on the industry will be greater than that presented in the proposed AD's economic analysis. This commenter states that numerous engines currently in their fleet, and engines to be delivered in 1999, will require premature removal due to the life reduction of the HPTR front air seal. The commenter further states that engines prematurely removed will still have serviceable life remaining at the time of removal. The FAA does not concur. The proposed AD's economic analysis already accounts for the cost impact associated with a premature removal of the HPTR front air seal due to the life reduction. Therefore, the FAA has determined that there is no need to revise the cost impact section of the AD.

One commenter supports the AD as proposed.

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

There are approximately 863 engines of the affected design in the worldwide fleet. The FAA estimates that 131 engines installed on aircraft of U.S. registry would be affected by this AD, and that it will not take any additional work hours per engine to accomplish the required actions. Assuming that the parts cost is proportional to the reduction of the LCF retirement lives, the required parts would cost approximately $14,000 per engine. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $1,834,000.

The regulations adopted herein will not have substantial direct effects 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. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is not a ``significant regulatory action'' under Executive Order 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (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.

   Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

   99-06-16 CFM International: Amendment 39-11079. Docket 98-ANE-56- AD.

   Applicability: CFM International CFM56-5 series turbofan engines installed on, but not limited to, Airbus A319 and A320 series aircraft.

   Note 1: This airworthiness directive (AD) applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (g) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

   Compliance: Required as indicated, unless accomplished previously.

   To prevent a low cycle fatigue failure of the high pressure turbine rotor (HPTR) front air seal, which could result in an uncontained engine failure and damage to the aircraft, accomplish the following:

   (a) Remove from service CFM International CFM56-5-A1 and -5-A1/F HPTR front air seals, Part Number (P/N) 1319M11P06, 1319M11P07, 1319M11P08, and 1319M11P09, and CFM56-5-A1 HPTR front air seals, P/N 1319M11P05, and replace with a serviceable part, in accordance with CFM56-5 Service Bulletin (SB) No. 72-541, dated July 27, 1998, as follows:

   (1) For seals that have accumulated less than 4,000 cycles since new (CSN) on the effective date of this AD, remove the seal from service prior to accumulating 11,000 CSN.

   (2) For seals that have accumulated 4,000 CSN or more, but less than 11,000 CSN on the effective date of this AD, accomplish the following:

   (i) For engines that have an engine shop visit (ESV) prior to the seal accumulating 11,000 CSN, remove the seal from service prior to the seal accumulating 11,000 CSN.

   (ii) For engines that do not have an ESV prior to the seal accumulating 11,000 CSN, remove the seal from service prior to the seal accumulating 7,000 cycles in service (CIS) after the effective date of this AD, or prior to the seal accumulating 15,300 CSN, whichever occurs first.

   (3) For seals that have accumulated 11,000 CSN or more on the effective date of this AD, remove the seal from service at the next ESV, or prior to the seal accumulating 15,300 CSN, whichever occurs first.

   (b) Remove from service CFM International CFM56-5A3 HPTR front air seals, P/N 1319M11P06, 1319M11P07, 1319M11P08, and 1319M11P09, and replace with a serviceable part, in accordance with CFM56-

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   5 SB No. 72-541, dated July 27, 1998, as follows:

   (1) For seals that have accumulated less than 3,000 CSN on the effective date of this AD, remove the seal from service prior to accumulating 7,700 CSN.

   (2) For seals that have accumulated 3,000 CSN or more, but less than 7,700 CSN on the effective date of this AD, accomplish the following:

   (i) For engines that have an ESV prior to the seal accumulating 7,700 CSN, remove the seal from service prior to the seal accumulating 7,700 CSN.

   (ii) For engines that do not have an ESV prior to the seal accumulating 7,700 CSN after the effective date of the AD, remove the seal from service prior to the seal accumulating 4,700 CIS after the effective date of this AD, or prior to the seal accumulating 13,000 CSN, whichever occurs first.

   (3) For seals that have accumulated 7,700 CSN or more on the effective date of this AD, remove the seal from service at the next ESV, or prior to the seal accumulating 13,000 CSN, whichever occurs first.

   (c) For CFM56-5A4, -5A4/F, -5A5, and -5A5/F HPTR front air seals, P/N 1319M11P05, 1319M11P06, 1319M11P07, 1319M11P08, and 1319M11P09, that have previously operated in CFM56-5-A1, -5-A1/F, or -5A3 engine models, recalculate the HPTR front air seal total cycles remaining using 11,000 cycles for the CFM56-5-A1 and CFM56-5-A1/F engine models, and 7,700 cycles for the CFM56-5A3 engine model, in accordance with CFM56-5 SB No. 72-541, dated July 27, 1998, within 750 CIS after the effective date of this AD.

   Note 2: The current HPTR front air seal retirement life for the CFM56-5A4, -5A4/F, -5A5, and -5A5/F engine models is 9,100 cycles, and is not affected by this AD.

   Note 3: For additional information on recalculating the HPTR front air seal total cycles remaining see Chapter 05, Section 05-11- 00, of the CFM56-5 series Engine Shop Manual, CFMI-TP.SM.7.

   (d) This AD establishes new LCF retirement lives of 11,000 cycles for CFM56-5-A1 and -5-A1/F HPTR front air seals, and 7,700 cycles for CFM56-5A3 HPTR front air seals, which is published in Chapter 05, Section 05-11-03, of the CFM56-5 series Engine Shop Manual, CFMI-TP.SM.7. The following conditions also apply:

   (1) Except as provided in paragraph (g) of this AD, no alternative retirement lives may be approved for the CFM56-5-A1, -5- A1/F, and -5A3 HPTR front air seals.

   (2) After the effective date of this AD, no CFM56-5-A1 and -5- A1/F HPTR front air seals may be installed or reinstalled on an engine if the seals have accumulated more than 11,000 CSN.

   (3) After the effective date of this AD, no CFM56-5A3 HPTR front air seals may be installed or reinstalled on an engine if the seals have accumulated more than 7,700 CSN.

   (e) For the purpose of this AD, an ``engine shop visit'' is defined as the induction of an engine into the shop for maintenance involving the separation of any major mating engine flanges, or the removal of a disk or spool, except that the separation of engine flanges solely for the purposes of transportation without subsequent engine maintenance does not constitute an engine shop visit.

   (f) For the purpose of this AD, a ``serviceable part'' is defined as one that has not exceeded its respective new retirement life as set out in this AD.

   (g) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office.

   Note 4: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.

   (h) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a location where the requirements of this AD can be accomplished.

   (i) The actions required by this AD shall be done in accordance with the following CFM International SB:

   Document No.

   Pages

   Date

   CFM56-5 SB No. 72-541....... 1-8................. July 27, 1998. Total Pages: 8.

   This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from CFM International, Technical Publications Department, 1 Neumann Way, Cincinnati, OH 45215; telephone (513) 552-2981, fax (513) 552-2816. Copies may be inspected at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street NW, suite 700, Washington, DC.

   (j) This amendment becomes effective on April 21, 1999.

   Issued in Burlington, Massachusetts, on March 11, 1999. David A. Downey, Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service.

   [FR Doc. 99-6555Filed3-19-99; 8:45 am]

   BILLING CODE 4910-13-P