E7-494. Airworthiness Directives; Turbomeca Arrius 2 F Turboshaft Engines

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 Turbomeca Arrius 2 F turboshaft engines. That AD currently requires removing from service certain serial number (SN) fuel control units (FCUs) or replacing the constant delta pressure diaphragm in those FCUs. This proposed AD would require replacing all FCUs not incorporating modification Tf 55 with FCUs that incorporate modification Tf 55. This proposed AD results from the European Aviation Safety Agency (EASA) and Turbomeca expanding the applicability to the full population of FCUs installed on Arrius 2 F turboshaft engines. FCUs not incorporating modification Tf 55 are susceptible to having an improperly assembled constant delta pressure (delta P) diaphragm. We are proposing this AD to prevent an uncommanded engine in-flight shutdown on a single-engine helicopter, resulting in a forced autorotation landing or an accident.

DATES:

We must receive any comments on this proposed AD by March 19, 2007.

ADDRESSES:

Use one of the following addresses to comment on this proposed AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-0001.
• Fax: [phone].
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Turbomeca, 40220 Tarnos, France; telephone [phone], fax [phone], for the service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Christopher Spinney, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; telephone [phone]; fax [phone].

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-2005-22430; Directorate Identifier 2005-NE-34-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://dms.dot.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://dms.dot.gov.

Examining the AD Docket

You may examine the docket that contains the proposal, any comments received and any final disposition in person at the DMS Docket Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone [phone]) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the DMS receives them.

Discussion

On September 9, 2005, the FAA issued AD 2005-19-10, Amendment 39-14275 (70 FR 54622, September 16, 2005). That AD requires removing from service certain SN FCUs or replacing the constant delta P diaphragm in those FCUs. The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, notified us that an unsafe condition may exist on Turbomeca Arrius 2 F turboshaft engines. EASA advises that the Arrius 2 F engine fleet is susceptible to having an improperly assembled constant delta pressure (delta P) diaphragm (pre-modification Tf 55) in the FCU.

Actions Since AD 2005-19-10 Was Issued

Since AD 2005-19-10 was issued, EASA issued AD No. 2006-0237, dated August 9, 2006, which expands the applicability to the full population of FCUs installed on Arrius 2 F turboshaft engines that have not incorporated modification Tf 55. Also, Turbomeca issued Mandatory Service Bulletin No. 319 73 4055, Update No. 1, dated March 17, 2006, to introduce modification Tf 55 to all Arrius 2 F FCUs. Modification Tf 55 upgrades the FCU with a constant delta P diaphragm that cannot be improperly assembled.

Bilateral Agreement Information

This engine model is manufactured in France and is type certificated for operation in the United States under the provisions of Section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Under this bilateral airworthiness agreement, EASA kept us informed of the situation described above. We have examined the findings of EASA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

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. We are proposing this AD, which would require replacing FCUs that do not incorporate modification Tf 55, with FCUs that do.

Costs of Compliance

We estimate that this proposed AD would affect 46 Arrius 2 F turboshaft engines installed on helicopters of U.S. registry. We also estimate that it would take about 3 work-hours per engine to perform the proposed FCU replacement and that the average labor rate is $80 per work-hour. Required parts would cost about $25,480 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $1,183,120.

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); 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.

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 Federal Aviation Administration 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 Amendment 39-14275 (70 FR 54622, September 16, 2005) and by adding a new airworthiness directive, to read as follows:

Turbomeca: Docket No. FAA-2005-22430; Directorate Identifier 2005-NE-34-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by March 19, 2007.

Affected ADs

(b) This AD supersedes AD 2005-19-10, Amendment 39-14275.

Applicability

(c) This AD applies to Turbomeca Arrius 2 F turboshaft engines with fuel control units (FCUs) not incorporating modification Tf 55. These engines are installed on, but not limited to, Eurocopter EC120B helicopters.

Unsafe Condition

(d) This AD results from the European Aviation Safety Agency (EASA) and Turbomeca expanding the applicability to the full population of FCUs installed on Arrius 2 F turboshaft engines. FCUs not incorporating modification Tf 55 are susceptible to having an improperly assembled constant delta pressure (delta P) diaphragm. We are issuing this AD to prevent an uncommanded engine in-flight shutdown on a single-engine helicopter, resulting in a forced autorotation landing or an accident.

Compliance

(e) You are responsible for having the actions required by this AD performed as soon as practicable after the effective date of this AD but no later than July 31, 2007, unless the actions have already been done.

(f) Replace all FCUs not incorporating modification Tf 55 with FCUs that incorporate modification Tf 55.

Alternative Methods of Compliance

(g) The Manager, Engine Certification Office, 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

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

(i) EASA AD No. 2006-0237, dated August 9, 2006, addresses the subject of this AD.

(j) Turbomeca Mandatory Service Bulletin, Update No. 1, dated March 17, 2006, pertains to the subject of this AD.

Issued in Burlington, Massachusetts, on January 10, 2007.

Francis A. Favara,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.