EASA AD No.: 2014-0036

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EASA AIRWORTHINESS DIRECTIVE

AD No.: 2014-0036

Date: 11 February 2014

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 accordance with EC 2042/2003 Annex I, Part M.A.301, the 

continuing airworthiness of an aircraft shall be ensured by accomplishing any applicable ADs. Consequently, no person may operate an 

aircraft to which an AD applies, except in accordance with the requirements of that AD, unless otherwise 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, Article 14(4) exemption].

Design Approval Holder’s Name:

TURBOMÉCA

Type/Model designation(s):

ARRIEL 1 and ARRIEL 2 engines

TCDS Number: EASA.E.073 and EASA.E.001

Foreign AD: Not applicable

Supersedure: None

ATA 72

Engine – Accessory Gear Box (M01) – 41/23 Tooth Bevel Gear 

Assembly – Check / Replacement

Manufacturer(s): Turbomeca S.A.

Applicability: ARRIEL 1A1, 1A2, 1B, 1C, 1C1, 1C2, 1D, 1D1, 1E2, 1K, 1K1, 1S and 1S1 

turbo-shaft engines, all serial numbers:

These engines are known to be installed on, but not limited to, Airbus 

Helicopters (formerly Eurocopter, Eurocopter France, Aerospatiale) AS 350 B, 

BA, BB, B1and B2, AS 365 and SA 365, Airbus Helicopters Deutschland

(formerly Eurocopter Deutschland, Messerschmidt-Bölkow-Blohm) MBBBK117-C1 and -C2, AgustaWestland (formerly Agusta) A 109 K2, and Sikorsky 

S-76A helicopters.

ARRIEL 2B, 2B1, 2B1A, 2B1B, 2C, 2C1, 2C2, 2S1 and 2S2 engines, all serial 

numbers:

These engines are known to be installed on, but not limited to, Eurocopter

AS 350 B3, EC 130 B4, AS 365 N3 and EC 155 B1, Changhe Z11 and Sikorsky 

S-76C helicopters.

Reason: Several cases of uncommanded in-flight shut-down (IFSD) have been reported 

on ARRIEL 1 or ARRIEL 2 engines following rupture of the 41-tooth gear 

forming part of the 41/23 tooth bevel gear located in the Accessory Gear Box 

(AGB) within engine Module M01.

Results of subsequent investigations showed that the meshing quality of the 

bevel gear may have contributed to tooth rupture.

The rupture of the AGB 41-tooth gear may lead to loss of driving of equipment 

essential to engine operation. 

This condition, if not detected and corrected, could lead to an uncommanded 

engine in-flight shut-down and may ultimately lead to an emergency landing.
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Prompted by these findings, Turbomeca has introduced into the engine 

acceptance test a vibration check to detect discrepancies of the meshing 

quality of the AGB 41/23 tooth bevel gear.

For the reasons described above, this AD requires accomplishment of vibration 

checks of the AGB 41/23 tooth bevel gear meshing on ARRIEL 1 and ARRIEL 

2 engines and depending on findings, accomplishment of corrective actions.

Effective Date: 25 February 2014

Required Action(s) 

and Compliance 

Time(s):

Required as indicated, unless accomplished previously:

One time action:

(1) For ARRIEL 1B, 1D and 1D1 engines, except for module M01 having a 

Serial Number (SN) listed in Figure 01 of Turbomeca Mandatory Service 

Bulletin (MSB) 292 72 0839 version B, and for ARRIEL 2B, 2B1, 2B1A and 

2B1B engines, except for module M01 having a SN listed in Figure 01 of 

Turbomeca MSB 292 72 2849 version B, within 32 months after the 

effective date of this AD, accomplish a one-time vibration check of the AGB 

41/23 tooth bevel gear meshing in accordance with Turbomeca applicable 

documents indicated in Appendix 1 of this AD, as applicable.

(2) If, during the vibration check as required by paragraph (1) of this AD, any 

discrepancy is identified, within the compliance times specified in Appendix 

1 of this AD, as applicable, replace the module M01 with a serviceable 

module M01.

Repetitive actions:

(3) For all engines affected by this AD, from the effective date of this AD,

during each qualifying shop visit (see Note 1 of this AD), accomplish a 

vibration check of the AGB 41/23 tooth bevel gear meshing in accordance 

with one of the applicable Turbomeca documents listed in Appendix 2 of 

this AD, as applicable.

Note 1: For the purpose of this AD, a qualifying shop visit is when an engine is 

removed from the helicopter and the module M01/engine is overhauled or 

repaired in a qualified Repair Center.

(4) If, during any vibration check as required by paragraph (3) of this AD, any 

discrepancy is identified, before release to service of the engine, replace 

the module M01 with a serviceable module M01.

Credits:

(5) Accomplishment of a vibration check of the AGB 41/23 tooth bevel gear 

meshing during a qualifying shop visit (see Note 1 of this AD) is acceptable 

to comply with the requirements of paragraphs (1) and (2) of this AD.

(6) Actions and corrective actions accomplished, before the effective date of 

this AD, in accordance with the instructions of Turbomeca MSB 292 72 

0839 version A or Turbomeca MSB 292 72 2849 version A, as applicable, 

are acceptable to comply with the requirements of paragraphs (1) and (2) 

of this AD, as applicable.

Ref. Publications: Turbomeca MSB 292 72 0839 version B dated 25 November 2013.

Turbomeca MSB 292 72 2849 version B dated 25 November 2013.

Turbomeca Technical Instruction (TI) X 292 72 0839 update 1.

Turbomeca TI X 292 72 2849 update 1.

Turbomeca TI X 292 72 0840 original issue.

Turbomeca TI X 292 72 2850 original issue.

Turbomeca Internal Directive (ID) 383952 version C.
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Turbomeca Repair Technical Directive (RTD) X 292 65 327 2.

Turbomeca Engine Test Bed Acceptance Test Specifications (CCT) as listed in 

Appendix 2 of this AD.

Turbomeca Maintenance Manuals (MM) as listed in Appendix 3 of this AD.

The use of later approved revisions of these documents 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 09 January 2014 as PAD 14-007 for consultation 

until 06 February 2014. 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, Executive Directorate, EASA. E-mail: ADs@easa.europa.eu.

4. For any question concerning the technical content of the requirements in 

this AD, please contact:

Turbomeca, S.A., ARRIEL 1 Customer Support,

40220 Tarnos, France, Fax: +33 5 59 74 45 15, or

contact your usual or nearest Turboméca technical representative at 

www.turbomeca-support.com.
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Appendix 1 – One-time Vibration Check

Engines Turbomeca Applicable Document Compliance time for the 

Corrective Actions

ARRIEL 1B, 1D 

and 1D1 

engines

MSB 292 72 0839 version B

and TI X 292 72 0839

Within the compliance times 

specified in Turbomeca MSB 

292 72 0839 version B 

paragraph 6.B.(1)

MSB 292 72 0839 version B

and TI X 292 72 0840, to be accomplished 

concurrent with accomplishment of task 

71-02-15-760-801-A01 of the applicable 

MM listed in Appendix 3

Before release to service of 

the engine

ARRIEL 2B, 

2B1, 2B1A and 

2B1B engines

MSB 292 72 2849 version B

and TI X 292 72 2849

Within the compliance times 

specified in Turbomeca MSB 

292 72 2849 version B

paragraph 6.B.(1)

MSB 292 72 2849 version B

and TI X 292 72 2850, to be accomplished 

concurrent with accomplishment of task 

71-02-15-760-801-A01 of the applicable 

MM listed in Appendix 3

Before release to service of 

the engine

Note 2: Turbomeca TI can be accomplished on engine installed on helicopter, or when the engine 

is removed from helicopter, as applicable.
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Appendix 2 – Applicable Turbomeca documents for module M01/engine repair/overhaul

Engine Test Bed Acceptance Test Specifications (CCT)

Engine CCT Reference

ARRIEL 1A1, 1A2, 1B 0292009400 version T

ARRIEL 1C, 1C1, 1C2, 1D, 1D1 0292019400 version R

ARRIEL 1E2 0292019690 version I

ARRIEL 1K, 1K1 0292019530 version K

ARRIEL 1S, 1S1 0292019610 version K

ARRIEL 2B 0292029450 version J

ARRIEL 2B1 0292029490 version I

ARRIEL 2B1A 0292029600 version F

ARRIEL 2B1B AA051773 version C

ARRIEL 2C 0292029440 version I

ARRIEL 2C1 0292029480 version K

ARRIEL 2C2 0292029520 version H

ARRIEL 2S1 0292029410 version L

ARRIEL 2S2 0292029530 version H

Or

Turbomeca ID 383952, for all engines;

Or

Turbomeca RTD X 292 65 327 2, for all engines.
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Appendix 3

Engine Maintenance Manuals (MM)

Engine Variant

Maintenance Manual (MM)

French Version English Version

ARRIEL 1B X 292 65 452 1 Issue 14 X 292 65 452 2 Issue 14

ARRIEL 1D X 292 E5 452 1 Issue 15 X 292 E5 452 2 Issue 15

ARRIEL 1D1 X 292 G2 452 1 Issue 15 X 292 G2 452 2 Issue 15

ARRIEL 2B X 292 M5 450 1 Issue 32 X 292 M5 450 2 Issue 32 

ARRIEL 2B1 X 292 N5 450 1 Issue 29 X 292 N5 450 2 Issue 29

ARRIEL 2B1A - X 292 P4 450 2 Issue 23

ARRIEL 2B1B - X 292 P6 450 2