Airworthiness Directives; Turbomeca Arriel 2S1 Turboshaft Engines

[Federal Register Volume 75, Number 30 (Tuesday, February 16, 2010)]
[Rules and Regulations]
[Pages 7027-7028]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-3000]



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Federal Register / Vol. 75, No. 30 / Tuesday, February 16, 2010 / 
Rules and Regulations

[[Page 7027]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0568; Directorate Identifier 2009-NE-20-AD; 
Amendment 39-16200; AD 2010-04-07]
RIN 2120-AA64


Airworthiness Directives; Turbomeca Arriel 2S1 Turboshaft Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We are adopting a new airworthiness directive (AD) for the 
products listed above. This AD results from mandatory continuing 
airworthiness information (MCAI) issued by an aviation authority of 
another country to identify and correct an unsafe condition on an 
aviation product. The MCAI describes the unsafe condition as:

    During acceleration up to One Engine Inoperative (OEI) 30-second 
rating, one event of flight loss of full automatic control occurred 
on an Arriel 2S1 engine.
    The selection of OEI 30-second rating on engine 1 was triggered 
by the automatic detection of an OEI situation further to a 
transient deceleration of engine 2. The transient deceleration of 
engine 2 was caused by the untimely reset of its digital electronic 
control unit (DECU). Once this reset was completed, engine 2 resumed 
its nominal operation. Afterwards the aircraft then continued its 
flight safely with its engine 1 operating in manual control mode.
    The loss of full automatic control of engine 1 was caused by 
loss of steps of the stepper motor controlling the fuel metering 
valve inside the Hydro-mechanical Unit (HMU).
    It has been found that high accelerations, notably up to OEI 30-
second rating, increase the risk of loss of steps of the HMU stepper 
motor.
    Therefore, this event has led to the consideration of the 
following unsafe condition at aircraft level: In-flight loss of full 
automatic control of the engine induced by the loss of steps of the 
stepper motor during acceleration up to OEI 30-second rating, 
further to an actual OEI situation on the other engine (such as a 
power loss event).

We are issuing this AD to prevent loss of full automatic control of the 
engine during acceleration up to the OEI 30-second rating. This 
condition could result in reduced controllability of the helicopter.

DATES: This AD becomes effective March 23, 2010.

ADDRESSES: The Docket Operations office is located at Docket Management 
Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, 
SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-
0001.

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: 
[email protected]; telephone (781) 238-7117; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: 

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an AD that would apply to the specified products. 
That NPRM was published in the Federal Register on October 28, 2009 (74 
FR 55491). That NPRM proposed to correct an unsafe condition for the 
specified products. The MCAI states:

    During acceleration up to OEI 30-second rating, one event of 
flight loss of full automatic control occurred on an Arriel 2S1 
engine.
    The selection of OEI 30-second rating on engine 1 was triggered 
by the automatic detection of an OEI situation further to a 
transient deceleration of engine 2. The transient deceleration of 
engine 2 was caused by the untimely reset of its DECU. Once this 
reset was completed, engine 2 resumed its nominal operation. 
Afterwards the aircraft then continued its flight safely with its 
engine 1 operating in manual control mode.
    The loss of full automatic control of engine 1 was caused by 
loss of steps of the stepper motor controlling the fuel metering 
valve inside the HMU.
    It has been found that high accelerations, notably up to OEI 30-
second rating, increase the risk of loss of steps of the HMU stepper 
motor.
    Therefore, this event has led to the consideration of the 
following unsafe condition at aircraft level: In-flight loss of full 
automatic control of the engine induced by the loss of steps of the 
stepper motor during acceleration up to OEI 30-second rating, 
further to an actual OEI situation on the other engine (such as a 
power loss event).

Comments

    We gave the public the opportunity to participate in developing 
this AD. We considered the comment received.
    One commenter, a private citizen, requests that in the 
applicability paragraph, we change ``S-76C+'' to ``S-76C'' which is how 
it is listed in the helicopter type certificate data sheet.
    We agree and changed the AD.

Conclusion

    We reviewed the available data, including the comment received, and 
determined that air safety and the public interest require adopting the 
AD with the change described previously. We determined that these 
changes will not increase the economic burden on any operator or 
increase the scope of the AD.

Differences Between This AD and the MCAI or Service Information

    The MCAI requires performing the DECU software upgrade no later 
than August 31, 2010. This AD requires performing the DECU software 
upgrade within 350 operating hours after the effective date of the AD.

Costs of Compliance

    Based on the service information, we estimate that this AD will 
affect about 136 products of U.S. registry. We also estimate that it 
will take about 3 work-hours per product to comply with this AD. The 
average labor rate is $80 per work-hour. Required parts will cost about 
$3,500 per product. Based on these figures, we estimate the cost of the 
AD on U.S. operators to be $508,640.

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

[[Page 7028]]

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.

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 (800) 647-5527) is provided in 
the ADDRESSES section. Comments will be available in the AD docket 
shortly after receipt.

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 adding the following new AD:

2010-04-07 Turbomeca: Amendment 39-16200. Docket No. FAA-2009-0568; 
Directorate Identifier 2009-NE-20-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective March 
23, 2010.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Turbomeca Arriel 2S1 turboshaft engines 
that have not incorporated Modification TU 109. These engines are 
installed on, but not limited to, Sikorsky S-76C twin-engine 
helicopters.

Reason

    (d) This AD results from mandatory continuing airworthiness 
information (MCAI) issued by an aviation authority of another 
country to identify and correct an unsafe condition on an aviation 
product. We are issuing this AD to prevent loss of full automatic 
control of the engine during acceleration up to the One Engine 
Inoperative 30-second rating. This condition could result in reduced 
controllability of the helicopter.

Actions and Compliance

    (e) Unless already done, do the following actions:
    (1) Within 350 operating hours after the effective date of this 
AD, perform an upgrade of the digital electronic control unit (DECU) 
software to version 11.01, to implement modification TU 109.
    (2) Guidance on implementing TU 109 can be found in Turbomeca 
Mandatory Service Bulletin No. 292 73 2109, Version E, dated 
September 17, 2008.

Prohibition of Mixed DECU Software Versions on the Same Helicopter

    (3) Do not operate an Arriel 2S1-powered twin-engine helicopter 
with one engine upgraded to modification TU 109 if the other engine 
is not upgraded to modification TU 109.

FAA AD Differences

    (f) This AD differs from the Mandatory Continuing Airworthiness 
Information (MCAI) and/or service information as follows:
    (1) The MCAI requires performing the DECU software upgrade no 
later than August 31, 2010.
    (2) This proposed AD would require performing the DECU software 
upgrade within 350 operating hours after the effective date of the 
proposed AD.

Alternative Methods of Compliance (AMOCs)

    (g) 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

    (h) Refer to MCAI EASA Airworthiness Directive 2009-0010, dated 
January 20, 2009, and Turbomeca Mandatory Service Bulletin No. 292 
73 2109, Version E, dated September 17, 2008, for related 
information. 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 AD.
    (i) Contact Kevin Dickert, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
[email protected]; telephone (781) 238-7117; fax (781) 238-7199, 
for more information about this AD.

Material Incorporated by Reference

    (j) None.

    Issued in Burlington, Massachusetts, on February 8, 2010.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2010-3000 Filed 2-12-10; 8:45 am]
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