AD 2007-19-09

This AD becomes effective October 3, 2007.

We must receive comments on this AD by October 18, 2007.

You may send comments by any of the following methods:

• DOT Docket Web Site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.

• 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: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

• Fax: (202) 493-2251.

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

Christopher Spinney, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: christopher.spinney@faa.gov; telephone (781) 238-7175, fax (781) 238-7199.

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued AD 2007-0126, dated May 7, 2007, to correct an unsafe condition for the specified products. The EASA AD states:

This AD is prompted by several reported cases of rupture of the constant delta pressure valve diaphragm on Arriel 2B1 engines, due to the wear of the delta P diaphragm fabric. Rupture can result in the loss of the automatic control mode of the helicopter, accompanied with a deterioration of the behavior of the auxiliary back-up mode (emergency mode). On a single-engine helicopter, the result may be an emergency landing or, at worst, an accident.

This AD supersedes AD EASA AD 2007-0006 which required the removal from service of all the delta pressure valve diaphragms logging more than 2,000 hours-since-new.

Since issuance of EASA AD 2007-0006, no further case of rupture of the constant delta pressure valve diaphragm has been reported on Arriel 2 engines. However, about 40 additional diaphragms returning from service have been inspected by Turbomeca, and some signs of wear have been detected on diaphragms having logged less than 2,000 hours. Based on the inspection results, it has been decided to decrease this limit from 2,000 hours to 1,500 hours in order to further reduce the probability of delta P diaphragm rupture.

The loss of automatic control mode coupled with the deteriorated performance of the backup mode can lead to the inability to continue safe flight, forced autorotation landing, or an accident. You may obtain further information by examining the EASA AD in the AD docket.

This AD supersedes AD 2007-03-14, Amendment 39-14925 (72 FR 4948, February 2, 2007), which we issued in response to EASA AD 2007-0006, dated January 9, 2007.

Turbomeca has issued Mandatory Service Bulletin No. 292 73 2818, Original Issue, dated October 18, 2006, and Update No. 1, dated April 3, 2007. The actions described in this service information are intended to correct the unsafe condition identified in the MCAI.

This product has been approved by the aviation authority of France and is approved for operation in the United States. Pursuant to our bilateral agreement with France, they have notified us of the unsafe condition described in the EASA AD and service information referenced above. We are issuing this AD because we evaluated all the information provided by EASA and determined the unsafe condition exists and is likely to exist or develop on other products of the same type design. This AD requires initial and repetitive replacement of the HMU with a serviceable HMU every 1,500 hours-in-service.

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 high risk to engines that could experience a ruptured delta P diaphragm with HMUs that have accumulated over 1,500 operating hours. Therefore, we determined that notice and opportunity for public comment before issuing this AD are impracticable and that good cause exists for making this amendment effective in fewer than 30 days.

This AD is a final rule that involves requirements affecting flight safety, and we did not precede it by notice and opportunity for public comment. We invite you to send any written relevant data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2007-27009; Directorate Identifier 2007-NE-02-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://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this AD.

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.

We 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 this 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. 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 regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket.

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 removing Amendment 39-14925 (72 FR 4948, February 2, 2007) and by adding the following new AD: