05-17493. Airworthiness Directives; General Electric Company CT7-5, -7, and -9 Series Turboprop 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) CT7-5A2, -5A3, -7A, -7A1, -9B, -9B1, and -9B2 turboprop engines, with stage 2 turbine aft cooling plate, part number (P/N) 6064T07P01, 6064T07P02, 6064T07P05, or 6068T36P01 installed. This AD requires a onetime eddy current inspection (ECI) of certain P/N stage 2 turbine aft cooling plate boltholes. This AD results from reports of six stage 2 turbine aft cooling plates found cracked during inspection. We are issuing this AD to prevent stage 2 aft cooling plate separation, resulting in uncontained engine failure and damage to the airplane.

DATES:

This AD becomes effective October 24, 2005. The Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulations as of October 24, 2005.

ADDRESSES:

You can get the service information identified in this AD from General Electric Aircraft Engines CT7 Series Turboprop Engines, 1000 Western Ave., Lynn, MA 01910; 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:

Eugene Triozzi, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

The FAA proposed to amend 14 CFR part 39 with a proposed AD. The proposed AD applies to GE CT7-5A2, -5A3, -7A, -7A1, -9B, -9B1, and -9B2 turboprop engines, with stage 2 turbine aft cooling plate, P/N 6064T07P01, 6064T07P02, 6064T07P05, or 6068T36P01 installed. We published the proposed AD in the Federal Register on April 15, 2005 (70 FR 19893). That action proposed to require a onetime ECI of certain P/N stage 2 turbine aft cooling plate boltholes.

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 Offices 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 Document Management Facility receives them.

Comments

We provided the public the opportunity to participate in the development of this AD. We received no comments on the proposal or on the determination of the cost to the public.

Conclusion

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

Costs of Compliance

There are about 1,240 GE CT7-5, -7, and -9 series turboprop engines of the affected design in the worldwide fleet. We estimate that 550 engines installed on airplanes of U.S. registry will be affected by this AD. We also estimate that it would take about one work hour per engine to perform the actions, and that the average labor rate is $65 per work hour. We estimate that 2.5% (or 14) of the 550 engines will require stage 2 turbine aft cooling plates being rejected by the onetime ECI. Required parts will cost about $17,000 per engine. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $270,700.

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
• Incorporation by reference
• 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:

2005-18-01 General Electric Company: Amendment 39-14241. Docket No. FAA-2005-20944; Directorate Identifier. 2003-NE-64-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective October 24, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to General Electric Company (GE) CT7-5A2, -5A3, -7A, -7A1, -9B, -9B1, and -9B2 turboprop engines, with stage 2 turbine aft cooling plate, part number (P/N) 6064T07P01, 6064T07P02, 6064T07P05, or 6068T36P01 installed. These engines are installed on, but not limited to, Construcciones Aeronauticas, SA CN-235 series and SAAB Aircraft AB SF340 series airplanes.

Unsafe Condition

(d) This AD results from reports of six stage 2 turbine aft cooling plates found cracked during inspection. The actions specified in this AD are intended to prevent stage 2 aft cooling plate separation, resulting in 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 engine or hot section module shop visit, but before accumulating an additional 6,000 cycles-in-service after the effective date of the AD, unless already done.

Onetime Eddy Current Inspection (ECI)

(f) Perform a onetime ECI of the stage 2 turbine aft cooling plate boltholes, using paragraph 3.B. of GE Alert Service Bulletin (ASB) No. CT7-TP S/B 72-A0464, Revision 2, dated May 9, 2003.

(g) Remove from service any stage 2 turbine aft cooling plate that does not pass the return to service criteria specified in paragraph 3.B.(2) of GE Alert Service Bulletin (ASB) No. CT7-TP S/B 72-A0464, Revision 2, dated May 9, 2003.

Previous Credit

(h) Previous credit is allowed for onetime ECIs of the stage 2 turbine aft cooling plate boltholes that were done using GE ASB No. CT7-TP S/B 72-A0464, dated February 25, 2003, or GE ASB No. CT7-TP S/B 72-A0464, Revision 1, dated March 12, 2003, before the effective date of this AD.

Definition of Engine or Hot Section Module Shop Visit

(i) For the purposes of this AD, an engine or hot section module shop visit is defined as the introduction of the engine or hot section module into a shop that includes separation of CT7 turboprop engine major case flanges.

Alternative Methods of Compliance

(j) 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

(k) None.

Issued in Burlington, Massachusetts, on August 19, 2005.

Material Incorporated by Reference

(l) You must use GE Alert Service Bulletin (ASB) No. CT7-TP S/B 72-A0464, Revision 2, dated May 9, 2003, to perform the inspection required by this AD. The Director of the Federal Register approved the incorporation by reference of this service bulletin in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact General Electric Aircraft Engines CT7 Series Turboprop Engines, 1000 Western Ave., Lynn, MA 01910; telephone [phone], fax [phone], for a copy of this service information. You may review copies at the Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-0001, on the Internet at http://dms.dot.gov, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/​federal-register/​cfr/​ibr-locations.html.

Issued in Burlington, Massachusetts, on August 19, 2005.

Richard Noll,

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