Skip to Content

Proposed Rule

Airworthiness Directives; Turbomeca Arriel 1B, 1D, 1D1, and 1S1 Turboshaft Engines

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

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 certain Turbomeca Arriel 1B, 1D, 1D1, and 1S1 turboshaft engines. That AD currently requires initial and repetitive position checks of the gas generator 2nd stage turbine blades on all Turbomeca Arriel 1B, 1D, 1D1, and 1S1 turboshaft engines. That AD also currently requires initial and repetitive replacements of 2nd stage turbines on 1B, 1D, and 1D1 engines only. This proposed AD would require adding a 3,000 hour life limit to Arriel 1B 2nd Stage Turbine Blades. This proposed AD results from reports of failures of second stage blades. We are proposing this AD to prevent failures of the 2nd stage turbine blades, which could result in uncommanded in-flight engine shutdown, and subsequent forced autorotation landing or accident.

DATES:

We must receive any comments on this proposed AD by May 8, 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: (202) 493-2251.
  • 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 (33) 05 59 74 40 00, fax (33) 05 59 74 45 15, for the service information identified in this proposed AD.

Start Further Info

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 (781) 238-7175, fax (781) 238-7199.

End Further Info End Preamble Start Supplemental Information

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-2005-21242; Directorate Identifier 2005-NE-09-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 (800) 647-5227) 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 August 8, 2006, the FAA issued AD 2006-02-08R1, Amendment 39-14721 (71 FR 46390, August 14, 2006). That AD requires initial and repetitive position checks of the gas generator 2nd stage turbine blades on all Turbomeca Arriel 1B, 1D, 1D1, and 1S1 turboshaft engines, and initial and repetitive replacements of 2nd stage turbines on 1B, 1D, and 1D1 engines only. The Direction Generale de L'Aviation Civile (DGAC), which is the airworthiness authority for France, notified the FAA that an unsafe condition might exist on Turbomeca, Arriel 1B (modified per TU 148), 1D, 1D1, and 1S1 turboshaft engines. The DGAC advises that sixteen cases of release of gas generator 2nd stage turbine blades occurred in service, with full containment of debris. These events resulted in uncommanded in-flight engine shutdowns. Although terminating action is still unavailable, mandatory checks of the turbine blades and replacement of the turbine are being required in order to reduce the probability of an uncommanded in-flight engine shutdown. That AD requires initial and repetitive position checks of the gas generator 2nd stage turbine blades on all Turbomeca Arriel 1B, 1D, 1D1, and 1S1 turboshaft engines. That AD also requires initial and repetitive replacements of 2nd stage turbines on 1B, 1D, and 1D1 engines only. That condition, if not corrected, could result in uncommanded in-flight engine shutdown.

Actions Since AD 2006-02-08R1 Was Issued

Since we issued that AD, the European Aviation Safety Agency (EASA) informed us that they have received reports of additional failures of the 2nd stage turbine blades. The debris from the failures was fully contained. The failures were caused by: Start Printed Page 10623

  • Deterioration of 2nd stage nozzle guide vanes (NGV2) modified to TU197,
  • Aerodynamic excitation from deteriorated NGV2,
  • Excessive temperature on the fir-tree roots, and
  • 2nd stage turbine blades modified to TU204.

Relevant Service Information

We have reviewed and approved the technical contents of Turbomeca Alert Service Bulletins (ASBs) A292 72 0807, Update 1, dated October 26, 2006, for Arriel 1B post-TU 148; ASB A292 72 0809, dated October 4, 2005, for Arriel 1D and 1D1; and ASB A292 72 0810, for Arriel 1S1, all dated March 24, 2004. These ASBs describe procedures for initial and repetitive position checks of the 2nd stage turbine blades, and replacement of 2nd stage turbines on 1B and 1D1 engines only. The EASA classified these ASBs as mandatory and issued airworthiness directive 2007-0018, dated January 15, 2007, in order to ensure the airworthiness of these Turbomeca Arriel 1B, 1D, 1D1, and 1S1 turboshaft engines in the European Union.

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. In keeping with this bilateral airworthiness agreement, the EASA, which is the airworthiness authority for the European Union, 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, which would require:

  • Initial and repetitive position checks of the 2nd stage turbine blades on Turbomeca Arriel 1B, 1D, 1D1, and 1S1 turboshaft engines.
  • Replacement of 2nd stage turbines on 1B and 1D1 engines only.
  • Initially replacing 2nd stage turbines in Arriel 1B, 1D, and 1D1 turboshaft engines.

The proposed AD would require that you do these actions using the service information described previously.

Costs of Compliance

We estimate that this proposed AD revision would affect 721 engines installed on helicopters of U.S. registry. We also estimate that it would take about 2 work-hours per engine to inspect all 721 engines and 40 work-hours per engine to replace about 587 2nd stage turbines on 1B and 1D1 engines, and that the average labor rate is $80 per work-hour. Required parts would cost about $3,200 per engine. Based on these figures, we estimate the total cost of the proposed AD revision to U.S. operators to be $3,905,240.

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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

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:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[Amended]

2. The FAA amends § 39.13 by removing Amendment 39-14721 (71 FR 46390, August 14, 2006) 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 May 8, 2007.

Affected ADs

(b) This AD supersedes AD 2006-02-08R1, Amendment 39-14721.

Applicability

(c) This AD applies to Turbomeca Arriel 1B engines fitted with 2nd stage turbine modification TU 148, and Arriel 1D, 1D1, and 1S1 engines. Arriel 1B engines are installed on, but not limited to, Eurocopter France AS-350B and AS-350A “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 S-76A and S-76C helicopters.

Unsafe Condition

(d) This AD results from reports of failures of second stage blades. We are issuing this AD to prevent failures of the 2nd stage turbine blades, which could result in uncommanded in-flight engine shutdown, and 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. Start Printed Page 10624

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 alert service bulletins (ASBs) 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 modelInitial relative position check intervalRepetitive intervalMandatory alert service bulletin
Arriel 1B (modified per TU 148)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 earlierWithin 200 hours time-in-service-since-last-relative-position-check (TSLRPC)A292 72 0807, Update 1, dated October 26, 2006.
Arriel 1D1 and Arriel 1DWithin 1,200 hours TSN or TSO or 3,500 hours CSN or CSO, whichever occurs earlierWithin 150 hours TSLRPCA292 72 0809, Update No. 1, dated October 4, 2005.
Arriel 1S1Within 1,200 hours TSN or TSO or 3,500 hours CSN or CSO, whichever occurs earlierWithin 150 hours TSLRPCA292 72 0810, dated March 24, 2004.

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 mandatory ASBs indicated.

Credit for Previous Relative Position Checks

(h) Relative position checks of 2nd stage turbine blades done using Turbomeca Service Bulletin A292 72 0263, Update 1, 2, 3, or 4, or A292 72 0807, dated March 24, 2004, comply with the initial requirements of paragraph (f) of this AD.

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

(i) Initially replace the 2nd stage turbine with a new or overhauled 2nd stage turbine as follows:

(1) Before accumulating 1,500 hours TSN or TSO on the module for Arriel 1D and 1D1 engines.

(2) Before accumulating 2,200 hours TSN or TSO on the module or 3,000 total hours TSN on the 2nd stage turbine blades, whichever occurs first, for Arriel 1B engines.

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

(j) Thereafter, replace the 2nd stage turbine with a new or overhauled 2nd stage turbine within every 1,500 hours TSN or TSO on the module for Arriel 1D and 1D1 engines, and within every 2,200 hours TSN or TSO on the module or 3,000 total hours TSN on the 2nd stage turbine blades, for Arriel 1B engines.

Criteria for Overhauled 2nd Stage Turbines

(k) Do the following to overhauled 2nd stage turbines, referenced in paragraphs (i) and (j) of this AD:

(1) You must install new blades in the 2nd stage turbines of overhauled Arriel 1D and 1D1 engines.

(2) You may install either overhauled blades with fewer than 3,000 total hours TSN or new blades in the 2nd stage turbines of overhauled Arriel 1B engines.

Relative Position Check Continuing Compliance Requirements

(l) All 2nd stage turbines, including those that are new or overhauled, must continue to comply with relative position check requirements of paragraphs (f) and (j) of this AD.

Alternative Methods of Compliance

(m) 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

(n) The EASA airworthiness directive 2007-0018, dated January 15, 2007, also addresses the subject of this AD.

(o) Contact Christopher Spinney, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: Christopher.spinney@faa.gov; telephone (781) 238-7175; fax (781) 238-7199, for more information about this AD.

Start Signature

Issued in Burlington, Massachusetts, on March 5, 2007.

Peter A. White,

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

End Signature End Part End Supplemental Information

[FR Doc. E7-4244 Filed 3-8-07; 8:45 am]

BILLING CODE 4910-13-P