[Federal Register Volume 72, Number 46 (Friday, March 9, 2007)]
[Proposed Rules]
[Pages 10622-10624]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-4244]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-21242; Directorate Identifier 2005-NE-09-AD]
RIN 21207-AA64


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

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

ACTION: Notice of proposed rulemaking (NPRM).

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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.

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.

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:

[[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.

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.


Sec.  39.13  [Amended]

    2. The FAA amends Sec.  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.

[[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
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                                           Initial relative
        Turbomeca engine model              position check        Repetitive interval    Mandatory alert service
                                               interval                                          bulletin
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Arriel 1B (modified per TU 148)......  Within 1,200 hours time- Within 200 hours time-   A292 72 0807, Update 1,
                                        since-new (TSN) or       in-service-since-last-   dated October 26,
                                        time-since-overhaul      relative-position-       2006.
                                        (TSO) or 3,500 cycles-   check (TSLRPC).
                                        since-new (CSN) or
                                        cycles-since-overhaul
                                        (CSO), whichever
                                        occurs earlier.
Arriel 1D1 and Arriel 1D.............  Within 1,200 hours TSN   Within 150 hours TSLRPC  A292 72 0809, Update
                                        or TSO or 3,500 hours                             No. 1, dated October
                                        CSN or CSO, whichever                             4, 2005.
                                        occurs earlier.
Arriel 1S1...........................  Within 1,200 hours TSN   Within 150 hours TSLRPC  A292 72 0810, dated
                                        or TSO or 3,500 hours                             March 24, 2004.
                                        CSN or CSO, whichever
                                        occurs earlier.
----------------------------------------------------------------------------------------------------------------

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: 
[email protected]; telephone (781) 238-7175; fax (781) 
238-7199, for more information about this AD.

    Issued in Burlington, Massachusetts, on March 5, 2007.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E7-4244 Filed 3-8-07; 8:45 am]
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