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Airworthiness Directives; CFE Company Model CFE738-1-1B Turbofan Engines

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Information about this document as published in the Federal Register.

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Federal Aviation Administration, DOT.


Final rule.


This amendment adopts a new airworthiness directive (AD), applicable to CFE Company model CFE738-1-1B turbofan engines, that requires new life limits for certain HPC rotor components in all engines. This amendment is prompted by a reduction in the calculated service life of certain compressor rotor rotating parts to values below currently approved service lives. The actions specified by this AD are intended to prevent failure of certain HPC rotor components, which could result in an uncontained engine failure and damage to the airplane.


Effective January 16, 2001.


The rulemaking docket may be examined 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.

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Keith Mead, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone: (781) 238-7744, fax: (781) 238-7199.

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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 CFE Company Model CFE 738-1-1B turbofan engines was published in the Federal Register on December 14, 1998 (63 FR 68707). Based on additional material stress testing, the FAA published a supplemental notice of proposed rule making (SNPRM) on September 23, 1999 (64 FR 51484). That SNPRM removed the proposal that would have required a dimensional inspection of the curvic couplings for parts that contain a machining mismatch and would have required those parts to be removed from service. That SNPRM, however, also introduced a requirement to remove parts prior to a new reduced cyclic life limit for specific high pressure compressor rotating parts. Since those changes expanded the scope of the originally proposed rule, the FAA determined that it was necessary to reopen the comment period. At the time the SNPRM was published, the manufacturer anticipated that the proposed reduced limits may be increased based upon further testing and analysis for the stage 4 and 5 blisk and impeller aft shaft.

Comments Received

One comment was received. The manufacturer, using the data obtained from additional testing and analysis, and life analysis prediction techniques approved by the FAA, has requested that the cyclic life limits for the stage 4 and 5 blisk proposed in the published SNPRM be increased. This analysis showed that the life predictions of two of the three stage 4 and 5 blisk configurations met initial published part cyclic life requirements. The analysis showed that the life of the remaining stage 4 and 5 blisk configuration should be reduced from the previously approved cyclic life limit.

The FAA agrees with the revised limits for the stage 4 and 5 blisk. This final rule has been revised accordingly by removing two of the stage 4 and 5 blisk configurations listed in the SNPRM and listing the recalculated cyclic life for the third stage 4 and 5 blisk configuration.

In addition, reference to inspection work hours was removed from the economic analysis section. Inspection requirements for these parts were removed in the SNPRM, and are not applicable to this AD.

Economic Analysis

There are approximately 245 engines of the affected design in the worldwide fleet. The FAA estimates that 156 engines would be affected by this proposed AD. Required parts, on a pro-rated basis, would cost approximately $13,613 per engine. Based on these figures, the total cost impact of the proposed AD on US operators is estimated to be $2,123628.

Regulatory Impact

This rule does not have federalism implications, as defined in Executive Order 13132, because it 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. Accordingly, the FAA has not consulted with state Start Printed Page 68078authorities prior to publication of this rule.

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 the 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 is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

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List of Subjects in 14 CFR Part 39

  • Air transportation
  • Aircraft
  • Aviation safety
  • Safety
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Adoption of the Amendment

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Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

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

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2000-23-12 CFE Company: Amendment 39-11982. Docket No. 98-ANE-69-AD.

Applicability: CFE Company Model CFE738-1-1B turbofan engines, installed on but not limited to the Dassault Aviation Falcon 2000 series airplanes.

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 (c) 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 failure of certain high pressure compressor

(HPC) rotor components, which could result in an uncontained engine failure and damage to the airplane, accomplish the following:

(a) Remove from service certain stage 4 and 5 blisks and impeller aft shafts prior to exceeding the new cyclic life limits as follows, and replace with serviceable parts:

NomenclaturePart No. (P/N)Cyclic life limit
Stage 4 and 5 Blisk6079T74P086,700 cycles since new (CSN).
Impeller Aft Shaft6079T80P045,100 CSN.
6079T80P052,160 CSN.
6079T80P067,100 CSN.
6079T80P077,100 CSN.

(b) Except for the provisions of paragraph (c) of this AD, no parts, identified by P/N in paragraph (a) of this AD, that exceed the new life limits may be installed.

Alternative Methods of Compliance

(c) 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 (ECO). Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO.

Special Flight Permits

(d) 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 airplane to a location where the requirements of this AD can be accomplished.

Effective Date of This AD

(e) This amendment becomes effective on January 16, 2001.

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Issued in Burlington, Massachusetts, on November 6, 2000.

Donald Plouffe,

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

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[FR Doc. 00-28961 Filed 11-13-00; 8:45 am]