E7-17003. Airworthiness Directives; Turbomeca Arrius 2F Turboshaft Engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) provided by the aviation authority of France to identify and correct an unsafe condition on Turbomeca Arrius 2F turboshaft engines. The MCAI states the following:

This AD is issued following a case of non-commanded in-flight engine shutdown which occurred on an Arrius 2F turboshaft engine, following the seizing of the gas generator. The result may be an emergency autorotation landing, or, at worst, an accident.

Investigations of this event have revealed that the seizing of the gas generator was caused by the fracture of the separator cage of the gas generator front bearing, due to high-cycle fatigue cracks initiated in the lubrication slots of the separator cage.

We are proposing this AD to prevent uncommanded shutdown of the engine, which could lead to an accident.

DATES:

We must receive comments on this proposed AD by September 27, 2007.

ADDRESSES:

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

Examining the AD Docket

You may examine the AD docket on the Internet at http://dms.dot.gov;​; or in person at the Docket Management Facility 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 Office (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Christopher Spinney, Aerospace Engineer, Engine Certification Office, FAA, Engine and 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 any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2007-28053; Directorate Identifier 2007-NE-18-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD based on 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 proposed AD.

Discussion

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued AD 2007-0057, dated March 1, 2007, to correct an unsafe condition for the specified products. The EASA AD states:

This AD is issued following a case of non-commanded in-flight engine shutdown which occurred on an Arrius 2F turboshaft engine, following the seizing of the gas generator. The result may be an emergency autorotation landing, or, at worst, an accident.

Investigations of this event have revealed that the seizing of the gas generator was caused by the fracture of the separator cage of the gas generator front bearing, due to high-cycle fatigue cracks initiated in the lubrication slots of the separator cage.

Modification Tf 12 introduces a new gas generator front bearing without lubrication slots on the separator cage.

You may obtain further information by examining the EASA AD in the AD docket.

Relevant Service Information

Turbomeca has issued Mandatory Service Bulletin No. 319 72 4012, Update No. 1, dated September 19, 2006. The actions described in this service information are intended to correct the unsafe condition identified in the EASA AD.

FAA's Determination and Requirements of This Proposed AD

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 proposing this AD because we evaluated all 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 proposed AD would require replacing the engine module 02 with a module that incorporates Turbomeca Modification Tf 12A. That replacement must occur at the next engine shop visit after the effective date of the proposed AD, but no later than April 30, 2008. Modification Tf 12A installs into the engine module 02, a new gas generator front bearing without lubrication slots on the separator cage.

Costs of Compliance

We estimate that this proposed AD would affect 61 engines installed on aircraft of U.S. registry. We also estimate that it would take about 10 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 $111,440 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $6,846,640. Our cost estimate is exclusive of possible warranty coverage.

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 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 this proposed regulation:

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 proposed AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA 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 AD:

Turbomeca: Docket No. FAA-2007-28053; Directorate Identifier 2007-NE-18-AD.

Comments Due Date

(a) We must receive comments by September 27, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Turbomeca Arrius 2F turboshaft engines that have not incorporated Turbomeca Modification Tf 12A. These engines are installed on, but not limited to, Eurocopter EC120B helicopters.

Reason

(d) European Aviation Safety Agency (EASA) AD No. 2007-0057, dated March 1, 2007, states:

This AD is issued following a case of non-commanded in-flight engine shutdown which occurred on an Arrius 2F turboshaft engine, following the seizing of the gas generator. The result may be an emergency autorotation landing, or, at worst, an accident.

Investigations of this event have revealed that the seizing of the gas generator was caused by the fracture of the separator cage of the gas generator front bearing, due to high-cycle fatigue cracks initiated in the lubrication slots of the separator cage.

Modification Tf12 introduces a new gas generator front bearing without lubrication slots on the separator cage.

Actions and Compliance

(e) Unless already done, do the following actions.

(1) At the next engine shop visit after the effective date of this AD, but no later than April 30, 2008, replace the engine module 02 with a module that incorporates Turbomeca Modification Tf 12A. Turbomeca Modification Tf 12A installs into the engine module 02 a new gas generator front bearing without lubrication slots on the separator cage.

(2) Use the Instructions to be Incorporated section of Turbomeca Mandatory Service Bulletin No. 319 72 4012, Update No. 1, dated September 19, 2006, to do the actions in paragraph (e)(1) of this AD.

Other FAA AD Provisions

(f) Alternative Methods of Compliance (AMOCs): The Manager, Engine Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

Related Information

(g) Refer to EASA AD 2007-0057, dated March 1, 2007, for related information.

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

Issued in Burlington, Massachusetts, on August 22, 2007.

Mark A. Rumizen,

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