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: