05-24341. Airworthiness Directives; General Electric Company CF6-45A, CF6-50A, CF6-50C, and CF6-50E Series Turbofan Engines

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Final rule.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for General Electric Company (GE) CF6-45A, CF6-50A, CF6-50C, and CF6-50E series turbofan engines. This AD requires removing from service pre-GE Service Bulletin (SB) No. CF6-50S/B 72-1268 configuration low pressure turbine (LPT) stage 2 interstage seal assemblies and stage 3 interstage seal assemblies. This AD also requires installing new or reworked configuration stage 2 interstage seal assemblies and stage 3 interstage seal assemblies. This AD results from reports of fan mid shaft separation, leading to separation of the LPT stage 1 disk, disk overspeed, and uncontained engine failure. We are issuing this AD to prevent uncontained engine failure and damage to the airplane.

DATES:

This AD becomes effective January 26, 2006.

ADDRESSES:

You can get the service information referenced in this AD from General Electric Company via Lockheed Martin Technology Services, 10525 Chester Road, Suite C, Cincinnati, Ohio 45215, telephone [phone], fax [phone].

You may examine the AD docket on the Internet at http://dms.dot.gov or in Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Karen Curtis, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

The FAA proposed to amend 14 CFR part 39 with a proposed airworthiness directive (AD). The proposed AD applies to GE CF6-45A, CF6-50A, CF6-50C, and CF6-50E series turbofan engines. We published the proposed AD in the Federal Register on August 19, 2005 (70 FR 48660). That action proposed to require removing from service pre-GE SB No. CF6-50 S/B 72-1268 configuration LPT stage 2 interstage seal assemblies and stage 3 interstage seal assemblies. That action also proposed to require installing new or reworked configuration stage 2 interstage seal assemblies and stage 3 interstage seal assemblies.

Examining the AD Docket

You may examine the docket that contains the AD, any comments received, and any final disposition in person at the Docket Management Facility Docket Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone [phone]) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the DMS receives them.

Comments

We provided the public the opportunity to participate in the development of this AD. We have considered the three comments received. The commenters support the proposal.

Conclusion

We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD as proposed.

Costs of Compliance

There are about 2,079 CF6-45A, CF6-50A, CF6-50C, and CF6-50E series turbofan engines of the affected design in the worldwide fleet. We estimate that 790 engines installed on airplanes of U.S. registry will be affected by this AD. We also estimate that it will take about 5 work hours per engine to rework the stage 2 interstage seal assembly and the stage 3 interstage seal assembly. The average labor rate is $65 per work hour. We estimate that 90% of the affected engines will have the parts reworked, and 10% will have new parts installed. A new stage 2 interstage seal assembly and new stage 3 interstage seal assembly will cost about $26,758 per engine. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $2,344,957.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in subtitle VII, part A, subpart III, section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will 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.

For the reasons discussed above, I certify that this AD:

(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.

We prepared a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary at the address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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. The FAA amends § 39.13 by adding the following new airworthiness directive:

2005-26-06 General Electric Company: Amendment 39-14427. Docket No. FAA-2005-22124; Directorate Identifier. 2005-NE-21-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective January 26, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to General Electric Company (GE) CF6-45A, CF6-50A, CF6-50C, and CF6-50E series turbofan engines. These engines are installed on, but not limited to, Boeing DC10 and 747 series airplanes, and Airbus Industrie A300 series airplanes.

Unsafe Condition

(d) This AD results from reports of fan mid shaft separation, leading to separation of the low pressure turbine (LPT) stage 1 disk, disk overspeed, and uncontained engine failure. We are issuing this AD to prevent uncontained engine failure and damage to the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed at the next disassembly of the LPT stage 2 interstage seal assembly and stage 3 interstage seal assembly from the LPT stator after the effective date of this AD, but no later than December 31, 2010, unless the actions have already been done.

Stage 2 Interstage Seal Assemblies

(f) Remove from service the pre-GE Service Bulletin (SB) No. CF6-50 72-1268 configuration LPT stage 2 interstage seal assembly.

(g) Install a new or reworked configuration LPT stage 2 interstage seal assembly, part number (P/N) 9198M81G05, 2092M13G01, 2092M13G02, or 2092M13G03, or other FAA-approved equivalent part.

(h) Information on reworking the pre-SB No. CF6-50 S/B 72-1268 configuration stage 2 interstage seal assembly to the new configuration can be found in GE SB No. CF6-50 S/B 72-1268, dated December 16, 2004.

Stage 3 Interstage Seal Assemblies

(i) Remove from service the pre-SB No. CF6-50 S/B 72-1268 configuration stage 3 interstage seal assembly.

(j) Install a new or reworked configuration LPT stage 3 interstage seal assembly, P/N 9044M29G17 or 2092M14G01, or other FAA-approved equivalent part.

(k) Information on reworking the pre-SB No. CF6-50 S/B 72-1268 configuration stage 3 interstage seal assembly to the new configuration can be found in GE SB No. CF6-50 S/B 72-1268, dated December 16, 2004.

Prohibition of Pre-SB No. CF6-50 S/B 72-1268 Configurations

(l) After the effective date of this AD, do not install pre-SB No. CF6-50 S/B 72-1268 configuration LPT stage 2 interstage seal assemblies or stage 3 interstage seal assemblies into any engine.

Alternative Methods of Compliance

(m) The Manager, Engine Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19.

Related Information

(n) National Transportation Safety Board Safety Recommendation No. A-98-125, dated December 3, 1998, pertains to the subject of this AD.

Material Incorporated by Reference

(o) None.

Issued in Burlington, Massachusetts, on December 14, 2005.

Peter A. White,

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