EASA AD No.: 2011-0249

EASA Form 110 Page 1/2 

## EASA AIRWORTHINESS DIRECTIVE

AD No.: 2011-0249

Date: 22 December 2011

Note: This Airworthiness Directive (AD) is issued b y EASA, acting in accordance with Regulation (EC) No 216/2008 on behalf of the European Communit y, its Member States and of the European third countries that participate in the activities of EASA under Article 66 of that Regulation

This AD is issued in accordance with EC 1702/2003, Part 21A.3B. In accordance with EC 2042/2003 Annex I, Part M.A.301, the continuing airworthiness of an aircraft shall be en sured by accomplishing any applicable ADs. Conseque ntly, no person may operate an aircraft to which an AD applies, except in accordan ce with the requirements of that AD unless otherwis e specified by the Agency [EC 2042/2003 Annex I, Part M.A.303] or agreed with the Authority of the State of Registry [EC 216/2008, A rticle 14(4) exemption]. 

### Type Approval Holder’s Name :
TURBOMECA Type/Model designation(s) : ARRIEL 2 series engines

TCDS Number : EASA E.001

Foreign AD : Not applicable

Supersedure : None



### ATA 73 Engine Fuel & Control – Digital Engine Control Unit (DECU) – Identification / Replacement

Manufacturer(s): TURBOMECA
Applicability: ARRIEL 2C1, 2C2 and 2S2 turboshaft e ngines, all serial numbers. These engines are known to be installed on, but not limited to, Eurocopter EC 155 B, EC 155 B1 and Sikorsky S-76C helicopters.
Reason: An incident has been reported of a helicopt er which experienced a Digital Engine Control Unit (DECU) malfunction in flight fr om one of its ARRIEL 2C1 engines. The indicating system of the helicopter di splayed a “FADEC FAIL” message, with a concurrent loss of automatic contro l of the engine. The mission was aborted and the helicopter returned to its base without any further incident. The subsequent technical investigations carried out by Turboméca revealed that a Digital Engine Control Unit (DECU) assembly non-c onformity was at the origin of this event. Further investigations performed wit h the supplier of the DECU led to the conclusion that only a limited number of DEC U are potentially affected by this non-conformity. This condition, if not corrected, could lead to a l oss of automatic control on one or both engines installed on the same helicopter, p otentially resulting in an emergency landing of the helicopter. For the reasons described above, this AD requires r eplacement of each affected DECU with a serviceable part. This AD also prohibit s the installation of any unserviceable DECU on an engine.

Effective Date: 05 January 2012EASA AD No.: 2011-0249

EASA Form 110 Page 2/2 Required Action(s) and Compliance Time(s): Required as indicated, unless accomplished previous ly: (1) Within 50 Engine Hours (EH) after the effective date of this AD, determine if at least one of the engines installed on the helico pter is equipped with a DECU whose serial number (s/n) is listed in the Tab le (Figure) of Turboméca Mandatory Service Bulletin (MSB) A292 73 2845 version A. (2) For any helicopter fitted with two DECUs whose s/n are listed in the Table (Figure) of Turboméca Mandatory Service Bulletin (M SB) A292 73 2845 version A, within 50 EH after the effective date of this AD, replace one of the two DECUs with a serviceable part. (3) For any helicopter fitted with one DECU whose s /n is listed in the Table (Figure) of Turboméca MSB A292 73 2845 version A, w ithin 1 000 EH or 12 months, whichever occurs first after the effective date of this AD, replace the affected DECU with a serviceable part. (4) From the effective date of this AD, do not inst all a DECU whose s/n is listed in Table (Figure) of Turboméca MSB A292 73 2845 ver sion A on an engine, and do not install an engine having a DECU installe d whose s/n is listed in Table (Figure) of Turboméca MSB A292 73 2845 versio n A on a helicopter, unless the DECU is serviceable.
Definition: For the purpose of this AD, a serviceable DECU is:

• A part not having a s/n listed in the Table (Figur e) of Turboméca MSB A292 73 2845 version A, or

• A part having a s/n listed in the Table (Figure) o f MSB A292 73 2845 version A, provided this DECU has passed the inspection in accordance with the instructions of Turboméca MSB No. A292 73 2845 vers ion A.

Ref. Publications: TURBOMECA MSB A292 73 2845 versi on A, dated 19 December 2011. The use of later approved revisions of this documen t is acceptable for compliance with the requirements of this AD.

Remarks : 1. If requested and appropriately substantiated, EA SA can approve Alternative Methods of Compliance for this AD. 2. The required actions and the risk allowance have granted the issuance of a Final AD with Request for Comments, postponing the public consultation process after publication. 3. Enquiries regarding this AD should be referred t o the Safety Information Section, Executive Directorate, EASA. E-mail: ADs@easa.europa.eu

. 4. For any question concerning the technical conten t of the requirements in this AD, please contact: Turboméca, S.A., ARRIEL 1 & 2 Customer Support 40220 Tarnos – France Fax: +33 (0)5 59 74 45 15 or contact your nearest technical representative at www.turbomeca-support.com.