2010-5028. Airworthiness Directives; Turbomeca Arriel 1B, 1D, 1D1, and 1S1 Turboshaft Engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) for certain Turbomeca Arriel 1B, 1D, 1D1, and 1S1 turboshaft engines. That AD requires initial and repetitive relative position checks of the gas generator 2nd stage turbine blades on Turbomeca Arriel 1B (that incorporate Turbomeca Modification (mod) TU 148), Arriel 1D, 1D1, and 1S1 turboshaft engines that do not incorporate mod TU 347. That AD also requires initial and repetitive replacements of 2nd stage turbines on Arriel 1B, 1D, and 1D1 engines. This proposed AD would require lowering the repetitive threshold for relative position checks on Arriel 1B engines. This proposed AD would also require lowering the initial and repetitive thresholds for replacement of 2nd stage turbines on Arriel 1B, 1D, and 1D1 engines. This proposed AD results from reports of new cases of failures of 2nd stage turbine blades since we issued AD 2008-07-01. We are proposing this AD to prevent the failure of 2nd stage turbine blades, which could result in an uncommanded in-flight engine shutdown, and a subsequent forced autorotation landing or accident.

DATES:

We must receive any comments on this proposed AD by April 9, 2010.

ADDRESSES:

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

• Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-0001.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
• Fax: [phone].

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

FOR FURTHER INFORMATION CONTACT:

Kevin Dickert, 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-2005-21242; Directorate Identifier 2005-NE-09-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://www.regulations.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 Web site, anyone can find and read the comments in any of our dockets, including, if provided, 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).

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone [phone]) is the same as the Mail address provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

Discussion

On March 17, 2008, the FAA issued AD 2008-07-01, Amendment 39-15442 (73 FR 15866, March 26, 2008). That AD requires initial and repetitive relative position checks of the gas generator 2nd stage turbine blades on Turbomeca Arriel 1B (that incorporate mod TU 148), 1D, 1D1, and 1S1 turboshaft engines that do not incorporate mod TU 347. That AD also requires initial and repetitive replacements of 2nd stage turbines on 1B, 1D, and 1D1 engines. The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, recently notified us that an unsafe condition likely exists on Turbomeca Arriel 1B, 1D, 1D1, and 1S1 turboshaft engines.

Since AD 2008-07-01 Was Issued

Since AD 2008-07-01 was issued, EASA reports that in engines that do not incorporate mod TU 347, new cases of gas generator 2nd stage turbine blade release have occurred, at lower blade service lives than previously reported. EASA issued AD 2009-0236, dated October 29, 2009, to optimize the 2nd stage turbine blade life limit and the replacement allowances for turbines currently in service in Europe, based on parts availability while keeping the risk level within acceptable limits.

Relevant Service Information

We have reviewed and approved the technical contents of Turbomeca Mandatory Service Bulletin (MSB) No. A292 72 0807, Version E, dated October 29, 2009, that describes procedures for the relative position check of 2nd stage turbine blades, and replacement of 2nd stage turbines that do not incorporate mod TU 347, with inspected 2nd stage turbines, or with 2nd stage turbines that incorporate mod TU 347, on Arriel 1B, 1D, and 1D1 engines. We have also reviewed and approved the technical contents of Turbomeca MSB No. A292 72 0810, Version C, dated July 24, 2009, that describes procedures for the relative position check of 2nd stage turbine blades on Arriel 1S1 engines. EASA classified these MSBs as mandatory and issued AD 2009-0236, dated October 29, 2009, to ensure the airworthiness of these Turbomeca Arriel engines in Europe.

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 the 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 supersedure, which would require lowering the repetitive threshold for relative position checks on Arriel 1B engines. This proposed AD would also require lowering the initial and repetitive thresholds for replacement of 2nd stage turbines on Arriel 1B, 1D, and 1D1 engines. The proposed AD would require that you do these actions using the service information described previously.

Costs of Compliance

Based on the service information, we estimate that this proposed AD would affect about 587 Turbomeca Arriel 1B, 1D, 1D1, and 1S1 turboshaft engines installed on products of U.S. registry. We also estimate that it would take about 2 work-hours per engine to perform one inspection, and about 40 work-hours per engine to replace the gas turbine discs and blades. The average labor rate is $85 per work-hour. Required parts would cost about $54,000 per engine. Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $33,793,590.

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 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. 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
• Incorporation by reference
• 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 39-15442 (73 FR 15866, March 26, 2008) and by adding a new airworthiness directive, to read as follows:

Turbomeca: Docket No. FAA-2005-21242; Directorate Identifier 2005-NE-09-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by April 9, 2010.

Affected ADs

(b) This AD supersedes AD 2008-07-01, Amendment 39-15442.

Applicability

(c) This AD applies to Turbomeca Arriel 1B (that incorporate Turbomeca Modification (mod) TU 148), Arriel 1D, 1D1, and 1S1 engines that do not incorporate mod TU 347. Arriel 1B engines are installed on, but not limited to, Eurocopter AS-350B and AS-350BA “Ecureuil” helicopters. Arriel 1D engines are installed on, but not limited to, Eurocopter France AS-350B1 “Ecureuil” helicopters. Arriel 1D1 engines are installed on, but not limited to, Eurocopter France AS-350B2 “Ecureuil” helicopters. Arriel 1S1 engines are installed on, but not limited to, Sikorsky Aircraft Corporation S-76C helicopters.

Unsafe Condition

(d) This AD results from reports of new cases of failures of 2nd stage turbine blades since we issued AD 2008-07-01. We are issuing this AD to prevent the failure of 2nd stage turbine blades, which could result in an uncommanded in-flight engine shutdown, and a subsequent forced autorotation landing or accident.

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.

Initial Relative Position Check of 2nd Stage Turbine Blades

(f) Do an initial relative position check of the 2nd stage turbine blades using the Turbomeca Mandatory Service Bulletins (MSBs) specified in the following Table 1. Do the check before reaching any of the intervals specified in Table 1 or within 50 hours time-in-service after the effective date of this AD, whichever occurs later.

Table 1—Initial and Repetitive Relative Position Check Intervals of 2nd Stage Turbine Blade

Turbomeca engine model	Initial relative position check interval	Repetitive interval	Mandatory service bulletin
Arriel 1B (that incorporate mod TU 148), 1D1, and 1D	Within 1,200 hours time-since-new (TSN) or time-since-overhaul (TSO) or 3,500 cycles-since-new (CSN) or cycles-since-overhaul (CSO), whichever occurs earlier	Within 150 hours time-in-service-since-last-relative-position-check (TSLRPC)	A292 72 0807, Version E, dated October 29, 2009, paragraphs 2B(1)(a) and (b), or 2B(2)(a).
Arriel 1S1	Within 1,200 hours TSN or TSO or 3,500 CSN or CSO, whichever occurs earlier	Within 150 hours TSLRPC	A292 72 0810, Version C, dated July 24, 2009, paragraphs 2B(1)(a) and (b), or 2B(2)(a), (b), and (c).

Repetitive Relative Position Check of 2nd Stage Turbine Blades

(g) Recheck the relative position of 2nd stage turbine blades at the TSLRPC intervals specified in Table 1 of this AD, using the Turbomeca MSBs indicated.

Credit for Previous Relative Position Checks

(h) Credit is allowed for previous relative position checks of 2nd stage turbine blades done using the following Turbomeca MSBs:

(1) MSB No. A292 72 0263, Update Nos. 1 through 5.

(2) MSB No. A292 72 0807, Original, and Update No. 1 through Version D.

(3) MSB No. A292 72 0809, Update No. 1.

(4) MSB No. A292 72 0810, Original, and Version A through Version B.

Initial Replacement of 2nd Stage Turbines on Arriel 1B Engines

(i) Initially replace the Arriel 1B 2nd stage turbine disk and blades with an inspected 2nd stage turbine that does not incorporate mod TU 347 and is fitted with new blades or with a 2nd stage turbine that incorporates mod TU 347, using Turbomeca MSB No. A292 72 0807, Version E, dated October 29, 2009, paragraphs 2B(1)(c) or (d), or 2B(2)(b) or (c), at the following times:

(1) Replace before further flight on engines with a 2nd stage turbine disk having accumulated more than 2,200 hours TIS since-new or since-last-inspection, whichever occurs later, or with 2nd stage turbine blades that have accumulated more than 3,000 hours TIS since-new.

(2) For engines with 2nd stage turbine blades having accumulated on the effective date of this AD, more than 1,800 hours TIS since-new, but 3,000 or fewer hours TIS since-new, replace before reaching any of the following:

(i) 400 hours TIS from the effective date of this AD, or

(ii) 3,000 hours TIS since-new on the 2nd stage turbine blades, or

(iii) 2,200 hours TIS since-new or since-last-inspection, whichever occurs later, on the 2nd stage turbine disk.

(3) For engines with 2nd stage turbine blades having accumulated on the effective date of this AD, more than 900 hours TIS since-new, but 1,800 or fewer hours TIS since-new, replace before reaching any of the following:

(i) 800 hours TIS from the effective date of this AD, or

(ii) 2,200 hours TIS since-new or since-last-inspection, whichever occurs later, on the 2nd stage turbine disk.

(4) For engines with 2nd stage turbine blades having accumulated on the effective date of this AD, 900 or fewer hours TIS since-new, replace before the 2nd stage turbine blades have accumulated 1,200 hours TIS since-new.

Repetitive Replacements of 2nd Stage Turbines on Arriel 1B Engines

(j) Thereafter, for 2nd stage turbines that do not incorporate mod TU 347, replace the 2nd stage turbine disk and blades before the blades have accumulated 1,200 hours TIS since-new.

Initial Replacement of 2nd Stage Turbines on Arriel 1D and 1D1 Engines

(k) Initially replace the Arriel 1D and 1D1 2nd stage turbine disk and blades with an inspected turbine that does not incorporate mod TU 347 and is fitted with new blades or with a turbine that incorporates mod TU 347, using Turbomeca MSB No. A292 72 0807, Version E, dated October 29, 2009, paragraphs 2B(1)(c) or (d), or 2B(2)(b) or (c), at the following times:

(1) Replace before further flight on engines with a 2nd stage turbine disk having accumulated more than 1,500 hours TIS since-new or since-last-inspection, whichever occurs later, or with 2nd stage turbine blades having accumulated more than 1,500 hours TIS since-new.

(2) For engines with 2nd stage turbine blades having accumulated on the effective date of this AD, more than 900 hours TIS since-new, but 1,500 or fewer hours TIS since-new, replace before the 2nd stage turbine blades have accumulated 1,500 hours TIS since-new, or before the 2nd stage turbine disk has accumulated 1,500 hours TIS since-new, whichever occurs first.

(3) For engines with 2nd stage turbine blades having accumulated on the effective date of this AD, 900 or fewer hours TIS since-new, replace before the 2nd stage turbine blades have accumulated 1,200 hours TIS since-new.

Repetitive Replacements of 2nd Stage Turbines on Arriel 1D and 1D1 Engines

(l) Thereafter, for 2nd stage turbines that do not incorporate mod TU 347, replace the 2nd stage turbine disk and blades before the blades have accumulated 1,200 hours TIS since-new.

Relative Position Check Continuing Compliance Requirements

(m) All 2nd stage turbines, including those that are new or overhauled, must continue to comply with the actions specified in paragraphs (f) and (g) of this AD, unless mod TU 347 has been incorporated.

Optional Terminating Action

(n) Installing a new turbine, P/N 0 292 25 039 0, (incorporation of mod TU 347) terminates the requirements to perform the repetitive actions specified in paragraphs (g), (j), and (l) of this AD.

Alternative Methods of Compliance

(o) 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

(p) The EASA airworthiness directive 2009-0236, dated October 29, 2009, also addresses the subject of this AD.

(q) Contact Kevin Dickert, 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 March 1, 2010.

Thomas A. Boudreau,

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