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Proposed Rule

Airworthiness Directives; General Electric Company Aircraft Engines (GEAE) CT7-8A Turboshaft Engines

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble Start Printed Page 14731

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) for certain GEAE CT7-8A turboshaft engines. That AD currently requires initial and repetitive inspections of the electrical chip detectors for the No. 3 bearing. This proposed AD would require removing certain GEAE CT7-8A turboshaft engines within 6,200 cycles-since-new. This proposed AD results from investigation for the root causes of two failures of the No. 3 bearing. We are proposing this AD to prevent failure of the No. 3 bearing due to contamination by Aluminum Oxide, which could result in a possible dual in-flight shutdown of the engines.

DATES:

We must receive any comments on this proposed AD by May 19, 2008.

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: (202) 493-2251.

Contact General Electric Aircraft Engines CT7 Series Turboprop Engines, 1000 Western Ave., Lynn, MA 01910; telephone (781) 594-3140, fax (781) 594-4805, for the service information identified in this proposed AD.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Christopher Richards, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: christopher.j.richards@faa.gov; telephone (731) 238-7133; fax (781) 238-7199.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2006-24261; Directorate Identifier 2006-NE-12-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 DMS Web site, anyone can find and read the comments in any of our dockets, including 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) or you may visit http://www.regulations.gov.

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 (800) 647-5527) is the same as the Mail address provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

Discussion

The FAA proposes to amend 14 CFR part 39 by superseding AD 2006-06-51, Amendment 39-14566 (71 FR 19627, April 17, 2006). That AD requires:

  • Within 25 hours time-in-service after the effective date of that AD, inspecting the electrical chip detector assembly.
  • Staggering the inspection intervals so the chip detectors on both engines on the same helicopter are not inspected at the same time.
  • Thereafter, within 25 hours time-since-last inspection, performing a repetitive inspection, and
  • If the chip detector assembly contains any bearing material, replacing the engine.

That AD was the result of two failures of the No. 3 bearing in GEAE CT7-8A turboshaft engines. That condition, if not corrected, could result in a possible dual in-flight shutdown of the engines.

Actions Since AD 2006-06-51 Was Issued

Since we issued that AD, GEAE has developed new procedures for flushing Aluminum Oxide hard particle contamination from the air cavity of the engine structure's front frame after the manufacturing process and for assembling the No. 3 bearing to the engine. Based on that new flushing procedure, we are proposing to:

  • Delete the requirements to inspect the electrical chip detector, and
  • Require removing any engine that has a serial number (SN) listed in Table 1 of this proposed AD unless the front frame was flushed and the No. 3 bearing replaced, and
  • Prohibit installing any engine that has a SN listed in Table 1 of this proposed AD unless the front frame was flushed and the No. 3 bearing replaced.

Relevant Service Information

We have reviewed and approved the technical contents of GEAE Service Bulletin (SB) CT7-8 S/B 72-0017, dated Start Printed Page 14732October 18, 2007, that describes procedures for flushing the engine front frame and replacing the No. 3 bearing.

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. For that reason, we are proposing this AD, which would require removing certain GEAE CT7-8A turboshaft engines, listed by SN in this proposed AD, from service within 6,200 cycles-since-new, and, after the effective date of the proposed AD, would prohibit installing certain GEAE CT7-8A turboshaft engines, listed by SN in this proposed AD.

Costs of Compliance

We estimate that this proposed AD would affect 29 engines installed on helicopters of U.S. registry. We also estimate that it would take about 66.0 work-hours per engine to perform the proposed actions, and that the average labor rate is $80 per work-hour. Required parts would cost about $3,476 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $253,924

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. See the ADDRESSES section for a location to examine the regulatory evaluation.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

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:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[Amended]

2. The FAA amends § 39.13 by removing Amendment 39-14566 (71 FR 19627, April 17, 2006) and by adding a new airworthiness directive to read as follows:

General Electric Company Aircraft Engines: Docket No. FAA-2006-24261; Directorate Identifier 2006-NE-12-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by May 19, 2008.

Affected ADs

(b) This AD supersedes AD 2006-06-51, Amendment 39-14566.

Applicability

(c) This AD applies to General Electric Company Aircraft Engines (GEAE) CT7-8A turboshaft engines that have a serial number (SN) listed in Table 1 of this AD. These engines are installed on, but not limited to, Sikorsky S92 helicopters.

Table 1.—Affected Engines by Serial Number

Engine Serial No.
947205 947206 947207 947208 947209 947210 947211 947212 947214 947215 947217 947218 947219 947220 947221 947223 947225947228 947230 947232 947233 947235 947238 947240 947241 947242 947243 947244 947245 947247 947248 947249 947250 947253947254 947255 947256 947258 947260 947261 947262 947263 947265 947266 947274 947277 947278 947279 947280 947284 947285

Unsafe Condition

(d) This AD results from investigation for the root causes of two failures of the No. 3 bearing. We are issuing this AD to prevent failure of the No. 3 bearing due to contamination by Aluminum Oxide, which could result in a possible dual in-flight shutdown of the engines.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.

(f) No further action is required if:

(1) Your engine has an SN that is not listed in Table 1 of this AD, or

(2) Your engine has an SN listed in Table 1 of this AD, but the engine log specifies that the front frame was flushed and the No. 3 bearing was replaced.

Engines With SNs Listed in Table 1 of This AD

(g) For engines with an SN listed in Table 1 of this AD, within 6,200 cycles-since-new, remove engine from service.

Installation Prohibition

(h) After the effective date of this AD, do not install any engine that has an SN listed in Table 1 of this AD unless the front frame was flushed and the No. 3 bearing was replaced. GEAE Service Bulletin (SB) CT7-8 S/B 72-0017, dated October 18, 2007, contains information on flushing the front frame and replacing the No. 3 bearing.

Alternative Methods of Compliance

(i) The Manager, Engine Certification Office, FAA, 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

(j) GEAE SB No. CT7-8 S/B 72-0017, dated October 18, 2007, pertains to the subject of this AD.

(k) Contact Christopher Richards, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Start Printed Page 14733Burlington, MA 01803; e-mail: christopher.j.richards@faa.gov; telephone (731) 238-7133; fax (781) 238-7199, for more information about this AD.

Start Signature

Issued in Burlington, Massachusetts, on March 12, 2008.

Robert J. Ganley,

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

End Signature End Part End Supplemental Information

[FR Doc. E8-5492 Filed 3-18-08; 8:45 am]

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