EASA AD No.: 20 15

- 0 1 77

TE. CAP.0011 0

- 00 4 © European Aviation Safety Agency. All rights reserved. 1 / 2 Proprietary document. Copies are not controlled. Confirm revision status through the EASA

- Internet/Intranet. 

## EASA AIRWORTHINESS DIRECTIVE

AD No

. : 20 15

- 0 1 7 7

Date: 25 August 2015

Note: This Airworthiness Directive (AD) is issued by EASA, acting in accordance with Regulation (EC) No 216/2008 on behalf of the European Community, 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 EU 748/2012, Part 21.A.3B. In accordan ce with EU 1321/2014 Annex I, Part M.A.301, the continuing airworthiness of an aircraft shall be ensured by accomplishing any applicable ADs. Consequently, no person may ope rate an aircraft to which an AD applies, except in accordance with the requirements of that AD, unless otherwise specified by the Agency [EU 1321/2014 Annex I, Part M.A.303] or agreed with the Authority of the State of Registry [EC 216/2008, Article 14(4) exemp tion].



### Design Approval Holder’s Name:

TURBOMECA Type/Model designation(s):

A RRIEL 2 e ngines

TCDS Number: EASA. E.001

F oreign AD: Not applicable

Supersedure: None



### ATA 7 2 Engine

– Torque Conformation B ox

– Check

Manufacturer(s): T urbomé ca S.A.

Applicability: ARRIEL 2C

, 2C1

, 2C2

, 2S1 and 2S2 engines, all serial numbers

, if incorporating
Turbom é ca modification (mod) TU 34 or mod TU34A

– “ Torque conformation box, increase of resistance to temperature ”

. These engines are k nown to be installed on, but not limited to, Airbus Helicopter s AS 365 N3, EC155 B/B1 and Sikorsky S

- 76C+, S76C++ helicopters.

Reason: Several cases of torque conformation box (TCB) failures have been reported on engines incorporating mod TU34 or mod TU34A . I nvestigation concluded that these failures were caused by cracks on soldered joints of TCB resistors.

This condition, if not corrected, could lead to limited power availability in a One Engine In o perative (OEI) case, possibly resulting in reduced control of the helicopter.

To address this unsafe condition, Turbo m é ca issued Mandatory Service Bulletin ( MSB ) 292 72 2860 version A providing instructions for TCB checks

. For the reasons described above, this AD requires repetitive TCB checks and, depending on findings, replacement of the TCB with a serviceable one. This AD also provides an optional terminating action for the required repetitive checks.

Effective Date: 0 8 September 2015EASA AD No.: 20 15

- 0 1 77

TE. CAP.0011 0

- 00 4 © European Aviation Safety Agency. All rights reserved. 2 / 2 Proprietary document. Copies are not controlled. Confirm revision status through the EASA

- Internet/Intranet. Required A ction(s)
and Compliance Time(s) : Required as indicated, unless accomplished previously:

(1) Within 600 engine flight hours (EH), or 6 months, whichever occurs first after the effective date of this AD, and, thereafter, at intervals not to exceed 600 EH, accomplish a torque conformation check (comprising two torque
conformation box resistance valu es check s ) in accordance with the
instructions of Turbo m é ca MSB 292 72 2860

.
Note: A non

- cumulative tolerance of 10% may be applied to the compliance times specified in paragraph (1) of this AD to allow synchronisation of the required inspections with other maintenance tasks for which a non

- cumulative tolerance is already granted in the applicable Engine Maintenance Manual.

(2) If, during any check as required by paragraph (1) of this AD, any discrepancy is identified, before next flight, replace the affected TCB with a serviceable
one in accordance with the instructions of Turbo m é ca MSB 292 72 2860

. (3 ) Replacement of the TCB on an engine with a serviceable TU34 or TU34A
TCB does not constitute terminating action for the repetitive checks required by paragraph (1) of this AD for that engine.

( 4 ) Modification of an engine in accordance with the instructions of Turboméca
SB 292

- 72

- 2188 constitutes terminating action for the repetitive checks as required by paragraph ( 2 ) of this AD for that engine , provided that, following modification, no mod TU34 TCB or mod TU34A TCB is re

- installed on that engine.

Ref. Public ations: Turbo m é ca MSB 292 72 2860 version A dated 15 July 2015.

Turbo m é ca MSB 292 72 2188 version A dated 02 July 2015

. The use of later approved revisions of th e s e document s is acceptable for compliance with the requirements of this AD.

Remarks: 1. If requested and appropriately substantiated, EASA can approve Alternative Methods of Compliance for this AD

.

2. This AD was posted on 2 2 July 2015 as PAD 15

- 0 94 for consultation until 19 August 2015. The Comment Response Document can be found at http://ad.easa.europa.eu

.
3. Enquiries regarding this AD should be referred to the Safety Information Section, Certification Directorate, EASA. E

- mail: ADs@easa.europa.eu

.

4. For any question concerning the technical content of the requirements in this AD, please contact: Turboméca S.A. , ARRIEL 2 Customer Support 40220 Tarnos, France Fax: +33 5 59 74 45 15, or your usual or nearest TURBOMECA technical

repres entative (refer to http://www.turbomeca

- support.com ).