AD 94-08-05

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AD Number:
94-08-05
Document Type:
AD Final Rules
Docket Number:
93-ANE-04
Subject Heading:
Airworthiness Directives; General Electric Company CF6 Series Turbofan Engines
Subject:
Fan Stator Case
Status:
Current
Citation:
Federal Register: May 05, 1994 (Volume 59, Number 86)
Citation Publish Date:
05/05/1994
Effective Date:
07/05/1994
Make:
General Electric Company
Model:
CF6-45A | CF6-45A2 | CF6-50A | CF6-50C | CF6-50C1 | CF6-50C2 | CF6-50C2B | CF6-50C2D | CF6-50CA | CF...Show more
Product Type:
Engine
Product Subtype:
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39 [59 FR 23138 NO. 86 05/05/94]
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 94-08-05
CITATION:   [Federal Register: May 05, 1994 (Volume 59, Number 86)]

PAGE NUMBER:   [Page 23138]

DOCKET NUMBER:   93-ANE-04

AMENDMENT:   39-8877

AD NUMBER:   94-08-05

SUBJECT HEADING:   Airworthiness Directives; General Electric Company CF6 Series Turbofan Engines

ACTION:   Final rule.

SUMMARY:   This amendment adopts a new airworthiness directive (AD), applicable to General Electric Company (GE) CF6-45/-50 series turbofan engines, that requires installation of a fan stator case stiffening ring assembly, and a new stage one fan shroud. This amendment is prompted by a report of an uncontained stage one fan blade failure, which resulted in an inflight engine shutdown, and damage to the aircraft. The actions specified by this AD are intended to prevent an uncontained stage one fan blade failure, which can result in an inflight engine shutdown, and damage to the aircraft.

DATES:   Effective July 5, 1994. The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of July 5, 1994.

ADDRESSES:   The service information referenced in this AD may be obtained from General Electric Aircraft Engines, CF6 Distribution Clerk, Room 132, 111 Merchant Street, Cincinnati, OH 45246.
This information may be examined at the Federal Aviation Administration (FAA), New England
Region, Office of the Assistant Chief 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 J. Ganley, Aerospace Engineer, Engine
Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park,
Burlington, MA 01803-5299, telephone (617) 238-7138; fax (617) 238-7199.

SUPPLEMENTARY INFORMATION:  

A proposal to amend part 39 of the Federal Aviation Regulations to include an airworthiness directive (AD) that is applicable to General Electric Company (GE) CF6- 45/-50 series turbofan engines was published in the Federal Register on January 11, 1994 (59 FR 1503). That action proposed to require installation of a fan stator case stiffening ring assembly and a new stage one fan shroud, which will result in reduced running clearances, and lower fan blade stresses. The compliance end date of December 31, 1996, ensures timely compliance without forced engine removals based on hardware availability. The actions would be required to be accomplished in accordance with GE CF6-50 Service Bulletin (SB) No. 72-573, Revision 5, dated September 15, 1981.

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

Two commenters support the rule as proposed.

One commenter states that the compliance end-date of August 31, 1995, in compliance paragraph (a) of the proposed rule should be extended to December 31, 1996, in order to avoid forced engine removals. The Federal Aviation Administration (FAA) concurs. The FAA has determined that flight safety will not be compromised by extending the compliance end-date to December 31, 1996. The final rule has been changed accordingly.

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 with the change described previously. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

There are approximately 67 GE CF6-45/-50 series turbofan engines of the affected design in the worldwide fleet. The FAA has been advised by the manufacturer that there are no engines on U.S. registered aircraft that would be affected by this AD. However, should an affected engine be imported on an aircraft and placed on the U.S. registry in the future, it would take approximately 48 work hours to accomplish the required actions, and that the average labor rate is $55 per work hour. Required parts will cost approximately $9,360 per engine. Based on these figures, the total cost impact of the AD is estimated to be $12,000 per engine.

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 14 CFR part 39 of the Federal Aviation Regulations as follows:

PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.

§39.13 - [AMENDED]
2. Section 39.13 is amended by adding the following new airworthiness directive:

REGULATORY TEXT:   94-08-05 General Electric Company: Amendment 39-8877. Docket 93-ANE-04.
Applicability: General Electric Company (GE) CF6-45/-50 series turbofan engines installed on, but not limited to, Airbus A300 series, Boeing 747 series, and McDonnell Douglas DC-10 series aircraft.
Compliance: Required as indicated, unless accomplished previously.
To prevent an uncontained stage one fan blade failure, which can result in inflight engine shutdown, and damage to the aircraft, accomplish the following:
(a) For engines that have not been modified in accordance with any revision level of GE CF6-50 Service Bulletin (SB) No. 72-573, prior to the effective date of this AD, install a fan stator case stiffening ring assembly and stage one fan shroud, in accordance with GE CF6-50 SB No. 72-573, Revision 5, dated September 15, 1981, by December 31, 1996.
(b) 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. The request should be forwarded through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office. NOTE: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.
(c) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the aircraft to a location where the requirements of this AD can be accomplished.
(d) The modification shall be done in accordance with the following service bulletin:

Document No.	Pages	Revision	Date
GE CF6-50 SB
No. 72-573	1-17	5	September 15, 1981
Total Pages: 17.			

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 General Electric Aircraft Engines, CF6 Distribution Clerk, Room 132, 111 Merchant Street, Cincinnati, OH 45246. Copies may be inspected at the FAA, New England Region, Office of the Assistant Chief 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.
(e) This amendment becomes effective on July 5, 1994.

FOOTER: