Airworthiness Directives; Turbomeca Arriel 2B1 Turboshaft Engines

[Federal Register Volume 72, Number 180 (Tuesday, September 18, 2007)]
[Rules and Regulations]
[Pages 53112-53114]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-18337]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-27009; Directorate Identifier 2007-NE-02-AD; 
Amendment 39-15200; AD 2007-19-09]
RIN 2120-AA64


Airworthiness Directives; Turbomeca Arriel 2B1 Turboshaft Engines

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

ACTION: Final rule; request for comments.

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SUMMARY: We are superseding an existing airworthiness directive (AD) by 
adopting a new AD for the products listed above. This AD results from 
mandatory continuing airworthiness information (MCAI) provided by the 
aviation authority of France to identify and correct an unsafe 
condition on Turbomeca Arriel 2B1 turboshaft engines. The MCAI states 
the following:

    This AD is prompted by several reported cases of rupture of the 
constant delta pressure valve diaphragm on Arriel 2B1 engines, due 
to the wear of the delta P diaphragm fabric. Rupture can result in 
the loss of the automatic control mode of the helicopter, 
accompanied with a deterioration of the behavior of the auxiliary 
back-up mode (emergency mode). On a single-engine helicopter, the 
result may be an emergency landing or, at worst, an accident.
    This AD supersedes European Aviation Safety Agency (EASA) AD 
2007-0006 which required the removal from service of all the delta 
pressure valve diaphragms logging more than 2,000 hours-since-new.
    Since issuance of EASA AD 2007-0006, no further case of rupture 
of the constant delta pressure valve diaphragm has been reported on 
Arriel 2 engines. However, about 40 additional diaphragms returning 
from service have been inspected by Turbomeca, and some signs of 
wear have been detected on diaphragms having logged less than 2,000 
hours. Based on the inspection results, it has been decided to 
decrease this limit from 2,000 hours to 1,500 hours in order to 
further reduce the probability of delta P diaphragm rupture.

We are issuing this AD to prevent forced autorotation landing, or an 
accident.

DATES: This AD becomes effective October 3, 2007.
    We must receive comments on this AD by October 18, 2007.

ADDRESSES: You may send comments by any of the following methods:
    <bullet> DOT Docket Web Site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
    <bullet> Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
    <bullet> Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    <bullet> Fax: (202) 493-2251.
    <bullet> Federal eRulemaking Portal: http://www.regulations.gov. 
Follow the instructions for submitting comments.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://dms.dot.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 (800) 647-5527) is the same as the Mail 
address provided in the ADDRESSES section. Comments will be available 
in the AD docket shortly after receipt.

FOR FURTHER INFORMATION 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.

SUPPLEMENTARY INFORMATION:

Discussion

    The European Aviation Safety Agency (EASA), which is the Technical 
Agent for the Member States of the European Community, has issued AD 
2007-0126, dated May 7, 2007, to correct an unsafe condition for the 
specified products. The EASA AD states:

    This AD is prompted by several reported cases of rupture of the 
constant delta pressure valve diaphragm on Arriel 2B1 engines, due 
to the wear of the delta P diaphragm fabric. Rupture can result in 
the loss of the automatic control mode of the helicopter, 
accompanied with a deterioration of the behavior of the auxiliary 
back-up mode (emergency mode). On a single-engine helicopter, the 
result may be an emergency landing or, at worst, an accident.
    This AD supersedes AD EASA AD 2007-0006 which required the 
removal from service of all the delta pressure valve diaphragms 
logging more than 2,000 hours-since-new.
    Since issuance of EASA AD 2007-0006, no further case of rupture 
of the constant delta pressure valve diaphragm has been reported on 
Arriel 2 engines. However, about 40 additional diaphragms returning 
from service have been inspected by Turbomeca, and some signs of 
wear have been detected on

[[Page 53113]]

diaphragms having logged less than 2,000 hours. Based on the 
inspection results, it has been decided to decrease this limit from 
2,000 hours to 1,500 hours in order to further reduce the 
probability of delta P diaphragm rupture.

    The loss of automatic control mode coupled with the deteriorated 
performance of the backup mode can lead to the inability to continue 
safe flight, forced autorotation landing, or an accident. You may 
obtain further information by examining the EASA AD in the AD docket.
    This AD supersedes AD 2007-03-14, Amendment 39-14925 (72 FR 4948, 
February 2, 2007), which we issued in response to EASA AD 2007-0006, 
dated January 9, 2007.

Relevant Service Information

    Turbomeca has issued Mandatory Service Bulletin No. 292 73 2818, 
Original Issue, dated October 18, 2006, and Update No. 1, dated April 
3, 2007. The actions described in this service information are intended 
to correct the unsafe condition identified in the MCAI.

FAA's Determination and Requirements of This AD

    This product has been approved by the aviation authority of France 
and is approved for operation in the United States. Pursuant to our 
bilateral agreement with France, they have notified us of the unsafe 
condition described in the EASA AD and service information referenced 
above. We are issuing this AD because we evaluated all the information 
provided by EASA and determined the unsafe condition exists and is 
likely to exist or develop on other products of the same type design. 
This AD requires initial and repetitive replacement of the HMU with a 
serviceable HMU every 1,500 hours-in-service.

FAA's Determination of the Effective Date

    An unsafe condition exists that requires the immediate adoption of 
this AD. The FAA has found that the risk to the flying public justifies 
waiving notice and comment prior to adoption of this rule because of 
the high risk to engines that could experience a ruptured delta P 
diaphragm with HMUs that have accumulated over 1,500 operating hours. 
Therefore, we determined that notice and opportunity for public comment 
before issuing this AD are impracticable and that good cause exists for 
making this amendment effective in fewer than 30 days.

Comments Invited

    This AD is a final rule that involves requirements affecting flight 
safety, and we did not precede it by notice and opportunity for public 
comment. We invite you to send any written relevant data, views, or 
arguments about this AD. Send your comments to an address listed under 
the ADDRESSES section. Include ``Docket No. FAA-2007-27009; Directorate 
Identifier 2007-NE-02-AD'' at the beginning of your comments. We 
specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of this AD. We will consider all 
comments received by the closing date and may amend this AD because 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 we 
receive about this AD.

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 determined that this AD will not have federalism implications 
under Executive Order 13132. This AD will 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 this 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. Will 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 AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by removing Amendment 39-14925 (72 FR 
4948, February 2, 2007) and by adding the following new AD:

2007-19-09 Turbomeca: Amendment 39-15200; Docket No. FAA-2007-27009; 
Directorate Identifier 2007-NE-02-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective October 
3, 2007.

Affected ADs

    (b) This AD supersedes AD 2007-03-14.

Applicability

    (c) This AD applies to Turbomeca Arriel 2B1 turboshaft engines. 
These engines are installed on, but not limited to, Eurocopter AS 
350 B3 and EC 130 B4 helicopters.

Reason

    (d) European Aviation Safety Agency (EASA) AD No. 2007-0126, 
dated May 7, 2007, states:

    This AD is prompted by several reported cases of rupture of the 
constant delta pressure valve diaphragm on Arriel 2B1 engines, due 
to the wear of the delta P diaphragm fabric. Rupture can result in 
the loss of the automatic control mode of the helicopter, 
accompanied with a deterioration of the behavior of the auxiliary 
back-up mode (emergency mode). On a single-engine helicopter, the 
result may be an emergency landing or, at worst, an accident.
    This AD supersedes EASA AD 2007-0006 which required the removal 
from service of all the delta pressure valve diaphragms logging more 
than 2,000 hours-since-new.
    Since issuance of EASA AD 2007-0006, no further case of rupture 
of the constant delta pressure valve diaphragm has been reported on 
Arriel 2 engines. However, about 40 additional diaphragms returning 
from service have been inspected by Turbomeca, and

[[Page 53114]]

some signs of wear have been detected on diaphragms having logged 
less than 2,000 hours. Based on the inspection results, it has been 
decided to decrease this limit from 2,000 hours to 1,500 hours in 
order to further reduce the probability of delta P diaphragm 
rupture.

The loss of automatic control mode coupled with the deteriorated 
performance of the backup mode can lead to the inability to continue 
safe flight, forced autorotation landing, or an accident.

Actions and Compliance

    (e) Unless already done, do the following actions.
    (1) Replace the HMU with a serviceable HMU before the HMU 
accumulates 1,500 hours-since-new, since-last-overhaul, or since-
incorporation of Turbomeca Service Bulletin (SB) No. 292 73 2105; or 
by July 30, 2007, whichever occurs later.
    (2) Thereafter, replace HMUs with a serviceable HMU at every 
1,500 hours-since-new, since-last-overhaul, or since-incorporation 
of Turbomeca SB No. 292 73 2105, whichever occurs later.
    (3) For the purposes of this AD, a serviceable HMU is an HMU 
fitted with a new constant delta P diaphragm in accordance with 
Turbomeca Service Bulletin (MSB) No. 292 73 2818, Original Issue, 
dated October 18, 2006, or Update No. 1, dated April 3, 2007.

Other FAA AD Provisions

    (f) Alternative Methods of Compliance (AMOCs): The Manager, 
Engine Certification Office, FAA, has the authority to approve AMOCs 
for this AD, if requested using the procedures found in 14 CFR 
39.19.

Related Information

    (g) 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.

Material Incorporated by Reference

    (h) None.

    Issued in Burlington, Massachusetts, on September 11, 2007.
Francis A. Favara,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
 [FR Doc. E7-18337 Filed 9-17-07; 8:45 am]
BILLING CODE 4910-13-P

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