2011-18171. Airworthiness Directives; Turbomeca Arriel 1 Series Turboshaft Engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to revise an existing airworthiness directive (AD) that applies to the products listed above. The existing AD currently requires removing from service certain gas generator second stage turbine discs, part number (P/N) 0 292 25 040 0, that are not marked with “CFR” before the discs exceed 2,500 cycles-in-service (CIS) since-new or within 20 CIS from the effective date of the AD, whichever occurs later. That AD also requires removing from service certain gas generator second stage turbine discs, P/N 0 292 25 040 0, that are marked with “CFR” before the discs exceed 3,500 CIS since-new. Since we issued that AD, Turbomeca has restored all or part of the life limits of the affected discs, and the European Aviation Safety Agency (EASA) issued AD 2010-0101R2, dated March 24, 2011 to do the same. This proposed AD would still prevent disc failure but extends the life limits of the affected discs. We are proposing this AD to prevent failure of the gas generator second stage turbine disc which could result in the release of high energy debris and damage to the helicopter.

DATES:

We must receive comments on this proposed AD by September 2, 2011.

ADDRESSES:

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: [phone].
• 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.

For service information identified in this AD, contact Turbomeca, 40220 Tarnos, France; phone: [phone], fax: [phone]. You may review copies of the referenced service information at the FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA. For information on the availability of this material at the FAA, call 781-238-7125.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.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 (phone: [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Rose Len, Aerospace Engineer, Engine Certification Office, FAA, 12 New England Executive Park, Burlington, MA 01803; phone: [phone]; fax: [phone]; e-mail: [e-mail].

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-2010-0710; Directorate Identifier 2010-NE-26-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 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 proposed AD.

Discussion

On September 10, 2010, we issued AD 2010-19-06, Amendment 39-16434 (75 FR 57371, September 21, 2010), for Turbomeca Arriel 1 series turboshaft engines. That AD requires removing from service gas generator second stage turbine discs, P/N 0 292 25 040 0 that do not have the “CFR” marking, before exceeding 2,500 CIS since-new or within 20 CIS from the effective date of the AD, whichever occurs later. That AD also requires removing from service gas generator second stage turbine discs, P/N 0 292 25 040 0 that have the “CFR” marking, before exceeding 3,500 CIS since-new. Discs that have the “CFR” marking have been inspected using a “reinforced” eddy-current inspection (ECI). Discs that do not have the “CFR” marking have not been inspected using the “reinforced” ECI. Based on the “reinforced” ECI and additional analysis finding performed by Turbomeca, the discs with the “CFR” marking are compliant with their original published life limit of 6,500 CIS since-new, and the life limit of discs with no “CFR” marking can be increased to 4,000 CIS since-new. AD 2010-19-06 resulted from Mandatory Continuing Airworthiness Information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. We issued that AD to prevent failure of the gas generator second stage turbine disc which could result in the release of high energy debris and damage to the helicopter.

Actions Since Existing AD Was Issued

Since we issued AD 2010-19-06, Turbomeca has restored all or part of the life limits of the affected discs, based on the reinforced eddy current inspection that provides an improved detection threshold of any metallurgical non-conformities in the discs, in combination with additional testing and analysis.

Also since we issued AD 2010-19-06, EASA has issued MCAI AD 2010-0101R2, dated March 24, 2011, which, for gas generator second stage turbine discs, P/N 0 292 25 040 0 that do not have the “CFR” marking, increases the life limit to 4,000 cycles, and for gas generator second stage turbine discs, P/N 0 292 25 040 0 that have the “CFR” marking, returns the life limit to the original published life limit of 6,500 cycles.

FAA's Determination

We are proposing 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.

Proposed AD Requirements

This proposed AD would require removing gas generator second stage turbine discs, P/N 0 292 25 040 0 that do not have the “CFR” marking, from service before exceeding 4,000 CIS since-new. This proposed AD would also require removing gas generator second stage turbine discs, P/N 0 292 25 040 0 that have the “CFR” marking, from service before exceeding 6,500 CIS since-new.

Costs of Compliance

We estimate that this proposed AD would affect 203 Turbomeca Arriel 1 series turboshaft engines on helicopters of U.S. registry. We estimate that no additional labor costs would be incurred to return part of the life limit of the discs that do not have the “CFR” marking, to the original published life limit. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $0.

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 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),

(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.

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 removing airworthiness directive (AD) 2010-19-06, Amendment 39-16434 (75 FR 57371 September 21, 2010), and adding the following new AD:

Turbomeca: Docket No. FAA-2010-0710; Directorate Identifier 2010-NE-26-AD.

(a) Comments Due Date

The FAA must receive comments on this AD action by September 2, 2011.

(b) Affected ADs

This AD revises AD 2010-19-06, Amendment 39-16434.

(c) Applicability

This AD applies to Turbomeca Arriel 1A, 1A1, 1B, 1C, 1C1, 1C2, 1D, 1D1, and 1S1 turboshaft engines that have incorporated Modification TU347.

(d) Unsafe Condition

This AD was prompted by Turbomeca restoring all or part of the life limits of the affected discs. We are issuing this AD to prevent failure of the gas generator second stage turbine disc which could result in the release of high energy debris and damage to the helicopter.

(e) Compliance

(1) Comply with this AD within the compliance times specified, unless already done.

(2) Remove from service gas generator second stage turbine discs, part number (P/N) 0 292 25 040 0 that do not have the “CFR” marking, before exceeding 4,000 cycles-in-service (CIS) since-new.

(3) Remove from service gas generator second stage turbine discs, P/N 0 292 25 040 0 that have the “CFR” marking, before exceeding 6,500 CIS since-new.

(4) Gas Generator Second Stage Turbine Installation Prohibition

(i) After the effective date of this AD, do not install into any engine gas generator second stage turbine discs, P/N 0 292 25 040 0 that do not have the “CFR” marking, and have 4,000 or more CIS since-new.

(ii) After the effective date of this AD, do not install into any engine gas generator second stage turbine discs, P/N 0 292 25 040 0 that have the “CFR” marking, and have 6,500 or more CIS since-new.

(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.

(g) Related Information

(1) Refer to Turbomeca Alert Mandatory Service Bulletin No. A292 72 0831, Version C, dated March 3, 2011, for related information. Contact Turbomeca, 40220 Tarnos, France; phone: [phone], fax: [phone], for a copy of this service information.

(2) You may review copies of the referenced service information at the FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA. For information on the availability of this material at the FAA, call 781-238-7125.

(3) For more information about this AD, contact Rose Len, Aerospace Engineer, Engine Certification Office, FAA, 12 New England Executive Park, Burlington, MA 01803; phone: [phone]; fax: [phone]; e-mail: [e-mail].

(h) Material Incorporated by Reference

None.

Issued in Burlington, Massachusetts, on July 13, 2011.

Colleen M. D'Alessandro,

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