Airworthiness Directive · Amendment 39-16200 · Turbomeca Arriel 2S1 Turboshaft Engines
Turbomeca Arriel 2S1 Turboshaft Engines
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.
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:
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.
(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.
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.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
