05-22007. Airworthiness Directives; Turbomeca Arriel 1B, 1D and 1D1 Turboshaft Engines

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for Turbomeca Arriel 1B, 1D and 1D1 turboshaft engines. This proposed AD would require inspecting the 2nd stage nozzle guide vanes (NGV2) for wall thickness. This proposed AD results from one instance of a fractured 2nd stage turbine blade followed by an uncommanded engine shutdown. We are proposing this AD to detect and prevent perforation of the NGV2 that could cause fracture of a turbine blade that could result in an uncommanded engine in-flight shutdown.

DATES:

We must receive any comments on this proposed AD by January 3, 2006.

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 S.A., 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 01803-5299; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send us any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2005-22364; Directorate Identifier 2005-NE-26-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 Docket Management Facility Docket Offices between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone [phone]) is 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 docket office receives them.

Discussion

The Direction Generale de L'Aviation Civile (DGAC), which is the airworthiness authority for France, notified us that an unsafe condition might exist on certain Turbomeca S.A. Arriel 1B, 1D and 1D1 turboshaft engines. The affected engines are those modified to TU 202, except those having NGV2 vanes with serial numbers or specific marks identified in Turbomeca Mandatory Service Bulletin (MSB) No. 292 72 0231, Update No. 5, dated July 22, 2004. The DGAC advises that in order to detect and prevent a possible perforation of the NGV2, they are requiring inspection of the NGV2 for wall thickness. Perforation of the NGV2 could cause an aerodynamic wake upstream of the 2nd stage turbine. Such a wake could lead to the fracture of a 2nd stage turbine blade followed by an uncommanded engine in-flight shutdown. On a single-engine helicopter, this in-flight shutdown could lead to an emergency landing by autorotation or an accident.

Relevant Service Information

We have reviewed and approved the technical contents of Turbomeca MSB No. 292 72 0231, Update No. 5, dated July 22, 2004, that describes procedures for removing each vane of the NGV2, checking the vane thickness, and replacing the NGV2 if the vane thickness is below the defined criteria. The DGAC classified this MSB as mandatory and issued airworthiness directive No. F-2004-088 R1, dated August 4, 2004, in order to ensure the airworthiness of these NGV2 vanes in France.

FAA's Determination and Requirements of the Proposed AD

These engines, manufactured in France, are 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. In keeping with this bilateral airworthiness agreement, the DGAC kept us informed of the situation described above. We have examined the DGAC's findings, 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. For this reason, we are proposing this AD, which would require inspection of the NGV2 wall thickness. The proposed AD would require you to use the service information described previously to perform these actions.

Costs of Compliance

There are about 2,000 Turbomeca Arriel 1B, 1D and 1D1 turboshaft engines of the affected design in the worldwide fleet. We estimate that this proposed AD would affect 571 engines installed on helicopters of U.S. registry. We also estimate that it would take about 0.5 work hours per engine to perform the proposed actions, and that the average labor rate is $65 per work hour. No parts are required. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $18,558.

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

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 adding the following new airworthiness directive:

Turbomeca: Docket No. FAA-2005-22364; Directorate Identifier 2005-NE-26-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by January 3, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Turbomeca Arriel 1B, 1D and 1D1 certain turboshaft engines, modified to TU 202. These engines are installed on, but not limited to, Eurocopter France AS350A, AS350B, AS350B1, and AS350B2 helicopters.

Unsafe Condition

(d) This AD results from one instance of a fractured 2nd stage turbine blade followed by an uncommanded engine shutdown. We are issuing this AD to detect and prevent perforation of the NGV2 that could cause fracture of a turbine blade that could result in an uncommanded engine in-flight shutdown.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.

Inspect 2nd Stage Nozzle Guide Vanes (NGV2)

(f) At the next shop visit or the next accessibility of the NGV2 after the effective date of this AD, whichever occurs first, check the thickness of the material on each NGV2 using the Instructions to be Incorporated of Turbomeca Mandatory Service Bulletin (MSB) No. 292 72 0231, Update No. 5, dated July 22, 2004. Replace the NGV2 if the vane thickness is below the defined criteria.

(g) Inspections carried out before the effective date of this AD, using an earlier update of MSB No. 292 72 0231, are acceptable alternatives to the requirements of this AD.

(h) Information regarding NGV2's that have already had the actions required by this AD done and are exempt from the inspections using paragraph (e) of this AD can be found in MSB No. 292 72 0231, Update No. 5, dated July 22, 2004.

Definitions

(i) For the purposes of this AD the following definitions apply:

(1) A shop visit is defined as introduction of the engine into a shop for the purposes of deep maintenance and the separation of a major mating flange.

(2) Accessibility of the NGV2 is defined as removal of the NGV2 from the engine regardless of the location or reason for removal.

Alternative Methods of Compliance (AMOCs)

(j) 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

(k) DGAC airworthiness directive No. F-20040-088 R1 also addresses the subject of this AD.

Issued in Burlington, Massachusetts, on October 31, 2005.

Francis A. Favara,

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