AD 2011-23-13

This AD is effective November 29, 2011.

We must receive comments on this AD by December 29, 2011.

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.

• Fax: (202) 493-2251.

• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590.

• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Robert Baitoo, Aerospace Engineer, Los Angeles Aircraft Certification Office, FAA, 3960 Paramount Blvd., Lakewood, CA 90712; phone: (562) 627-5245; fax: (562) 627-5210; email: robert.baitoo@faa.gov.

We received reports of two accidents where the engines suddenly lost power and the helicopters had to make emergency autorotation landings. Investigation revealed that PTG spool bearings, part number (P/N) 2523973 Revision N and P/N 2523973 Revision P, could fail prematurely. PTGs with these affected spool bearings require repetitive replacements before the spool bearings wear out prematurely. This condition, if not corrected, could result in sudden engine power loss, the helicopter making an emergency autorotation landing, and substantial damage to the helicopter.

We are issuing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.

This AD requires initial and repetitive replacements of PTGs model AL-AB1, P/N 4-301-289-03, 4-301-289-05, 4-301-289-09, 4-301-101-16, and 4-301-101-18, that are marked with compliance symbol N or P, or with no compliance symbol, on the PTG identification plate.

We consider this AD interim action. If final action is later identified, we might consider further rulemaking then.

An unsafe condition exists that requires the immediate adoption of this AD. The FAA has found that the risk to the flying public justifies waiving notice and comment prior to adoption of this rule because of the premature failure of the affected PTGs. Therefore, we find that notice and opportunity for prior public comment are impracticable and that good cause exists for making this amendment effective in less than 30 days.

This AD is a final rule that involves requirements affecting flight safety and was not preceded by notice and an opportunity for public comment. However, we invite you to send any written data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include the docket number FAA-2011-1159 and Directorate Identifier 2011-NE-34-AD at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this AD. We will consider all comments received by the closing date and may amend this AD because 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 we receive about this AD.

We estimate that this AD will affect 83 Honeywell International Inc. LTS101-600A-2, -3, -3A, and LTS101-700D-2 turboshaft engines, installed on helicopters of U.S. registry. We also estimate that it will take about 3 work-hours to replace a PTG on each engine. Required parts would cost about $3,500 per engine. The average labor rate is $85 per work-hour. Based on these figures, we estimate the total cost of this AD for one PTG replacement to U.S. operators, to be $311,665.

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.

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),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

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

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):