2010-17999. Airworthiness Directives; General Electric Company (GE) CT7-9C and -9C3 Turboprop Engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for GE CT7-9C and -9C3 turboprop engines with certain serial number (S/N) gas generator turbine (GGT) shafts, part number (P/N) 6068T44P02, installed. This proposed AD would require inspecting the GGT shaft for nonconforming land balance-cuts, and if found, removing the shaft from service. This proposed AD results from reports of a manufacturing quality problem. We are proposing this AD to detect nonconforming GGT shaft land balance-cuts, which could result in the shaft failing before its published life limit, and which could result in an uncontained engine failure and damage to the airplane.

DATES:

We must receive any comments on this proposed AD by September 21, 2010.

ADDRESSES:

Use one of the following addresses to comment on this proposed AD.

• Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-0001.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
• Fax: [phone].

Contact General Electric Company, GE-Aviation, Room 285, 1 Newmann Way, Cincinnati, Ohio 45215; e-mail [e-mail]; telephone [phone]; fax [phone], for a copy of the service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Barbara Caufield, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: [e-mail]; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send us any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2010-0732; Directorate Identifier 2010-NE-04-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of the Web site, anyone can find and read the comments in any of our dockets, including, if provided, the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78).

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone [phone]) is the same as the Mail address provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

Discussion

We have received reports of 21 nonconforming land balance-cuts on GGT shafts, P/N 6068T44P02. The nonconforming land balance-cuts can negatively affect the low-cycle fatigue life capability of the shaft. This condition, if not corrected, could result in the shaft failing before its published life limit, and which could result in an uncontained engine failure and damage to the airplane.

Relevant Service Information

We have reviewed and approved the technical contents of GE CT7-TP Alert Service Bulletin (ASB) 72-A0501, Revision 01, dated March 3, 2010, that lists the affected shafts by P/N and S/N, and describes procedures for inspecting the GGT shaft for nonconforming land balance-cuts.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other products of this same type design. We are proposing this AD, which would require inspecting certain S/N GGT shafts, P/N 6068T44P02, for nonconforming land balance-cuts, and if found, replacing the shaft. The proposed AD would require you to use the service information described previously to perform these actions.

Costs of Compliance

We estimate that this proposed AD would affect five engines installed on airplanes of U.S. registry. We also estimate that it would take about 1 work-hour per engine to perform the inspection, 1.5 work-hours to replace the shaft, and that the average labor rate is $85 per work-hour. Required parts would cost about $28,633 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $144,227.

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 proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

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

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. Would 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 regulatory evaluation of the estimated costs to comply with this proposed AD. 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

The Proposed Amendment

Under the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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:

General Electric Company (GE): Docket No. FAA-2010-0732; Directorate Identifier 2010-NE-04-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by September 21, 2010.

Affected ADs

(b) None.

Applicability

(c) This AD applies to GE CT7-9C and -9C3 turboprop engines with gas generator turbine (GGT) shafts, part number (P/N) 6068T44P02, that have a serial number (S/N) listed in Table 1 of this AD, installed. These engines are installed on, but not limited to, EADS CASA (formerly Construcciones Aeronauticas, S.A.) CN-235 series airplanes.

Table 1—Affected GGT Shaft S/Ns

Affected Shaft S/Ns
GATHHCPC	GATHHJR7	GATHHJR9	GATHHKG6
GATHHM9R	GATHHWM3	GATHJ4ED	GATHJ9FL
GATHJ19J	GATHJE8P	GATHJWWR	GATHK0KM
GATHK2N1	GATHK3M3	GATHK90K	GATHK96D
GATHKF9R	GATHKH36	GATHKMP7	GATHKRKN
NCE715DA

Unsafe Condition

(d) This AD results from reports of a manufacturing quality problem. We are issuing this AD to detect nonconforming GGT shaft land balance-cuts, which could result in the shaft failing before its published life limit, and which could result in an uncontained engine failure and damage to the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed at the first shop visit after the effective date of this AD, or within 5,000 cycles-since-new, whichever occurs first, unless the actions have already been done.

Inspection for Nonconforming Land Balance-Cuts

(f) For CT7-9C and -9C3 engines with a GGT shaft, P/N 6068T44P02, that has a S/N listed in Table 1 of this AD, installed, inspect the shaft for nonconforming land balance-cuts. Use the Accomplishment Instructions 3.A.(1) through 3.A.(4) of GE CT7-TP Alert Service Bulletin 72-A0501, Revision 01, dated March 3, 2010, to perform the inspection.

(g) If you find any nonconforming land balance-cuts, remove the shaft from service.

Alternative Methods of Compliance

(h) 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

(i) Contact Barbara Caufield, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: [e-mail]; telephone [phone]; fax [phone], for more information about this AD.

(j) GE CT7-TP Alert Service Bulletin 72-A0501, Revision 01, dated March 3, 2010, pertains to the subject of this AD. Contact General Electric Company, GE-Aviation, Room 285, 1 Newmann Way, Cincinnati, Ohio 45215; e-mail [e-mail]; telephone [phone]; fax [phone], for a copy of this service information.

Issued in Burlington, Massachusetts, on July 15, 2010.

Peter A. White,

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