AD 2003-09-06 ACTIVE

This amendment adopts a new airworthiness directive (AD), that is applicable to General Electric Company (GE) CF6-50 series turbofan engines. This amendment requires removal from service of eight serial number (SN) low-pressure turbine (LPT) stage 1 disks, part number (P/N) 9061M21P03, at the next engine shop visit. This amendment is prompted by a report of the potential for iron-rich inclusions introduced during manufacture in the affected disks. The actions specified by this AD are intended to prevent LPT stage 1 disk cracking, due to iron-rich inclusions introduced during manufacture, leading to uncontained disk failure.

Final rule.

2003-09-06 General Electric Company: Amendment 39-13135. Docket No. 2002-NE-35-AD.

Applicability: This airworthiness directive (AD) is applicable to General Electric Company CF6-50 series turbofan engines with low pressure turbine (LPT) stage 1 disks, part number (P/N) 9061M21P03, serial numbers (SNs) SNL17693, SNL17694, SNL44200, SNL47624, SNL47625, SNL47626, SNL47627, and SNL47628 installed. These engines are installed on, but not limited to Airbus Industrie A300, Boeing 747, and McDonnell Douglas DC-10 airplanes.

Note 1: This 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. Therequest 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: Compliance with this AD is required as indicated, unless already done.

To prevent LPT stage 1 disk cracking due to the potential for iron-rich inclusions introduced during manufacture, leading to uncontained disk failure, do the following:

(a) Remove from service LPT stage 1 disks P/N 9061M21P03, SNs SNL17693, SNL17694, SNL44200, SNL47624, SNL47625, SNL47626, SNL47627, and SNL47628 at the next engine shop visit.

(b) After the effective date of this AD, do not install any of the LPT stage 1 disks listed in paragraph (a) of this AD into any engine.

Alternative Methods of Compliance

(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable levelof safety may be used if approved by the Manager, Engine Certification Office (ECO). Operators must submit their request 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 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 done.

Effective Date

(e) This amendment becomes effective on June 3, 2003.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that is applicable to General Electric Company (GE) CF6-50 series turbofan engines was published in the Federal Register on December 27, 2002 (67 FR 79007). That action proposed to require removal from service of eight SN LPT stage 1 disks, P/N 9061M21P03, at the next engine shop visit.

Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Economic Analysis

There are approximately 2,101 CF6-50 series turbofan engines of the affected design in the worldwide fleet. The FAA estimates that no more than eight of the 469 engines installed on airplanes of U.S. registry will be affected by this AD, that it will take approximately 32 work hours per engine to perform the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $75,490 per engine. Based on these figures, the total cost of the AD to eight U.S. operators is estimated to be $619,280.

Regulatory Analysis

This final 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 authorities prior to publication of this final 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 it 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.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, 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.

39.13 [Amended]

2. Section 39.13 is amended by adding a new airworthiness directive to read as follows:

Karen Curtis, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone: (781)
238-7192; fax: (781) 238-7199.