EASA AD No.: 2016-0055

TE.CAP.00110-005 © European Aviation Safety Agency. All rights reserved. ISO9001 Certified.

Proprietary document. Copies are not controlled. Confirm revision status through the EASA-Internet/Intranet.

An agency of the European Union

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Airworthiness Directive

AD No.: 2016-0055

Issued: 17 March 2016

Note: This Airworthiness Directive (AD) is issued by EASA, acting in accordance with Regulation 

(EC) 216/2008 on behalf of the European Union, 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 Regulation (EU) 748/2012, Part 21.A.3B. In accordance with Regulation (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 operate an aircraft to which 

an AD applies, except in accordance with the requirements of that AD, unless otherwise specified by the Agency [Regulation (EU) 1321/2014 Annex I, 

Part M.A.303] or agreed with the Authority of the State of Registry [Regulation (EC) 216/2008, Article 14(4) exemption].

Design Approval Holder’s Name:

TURBOMECA

Type/Model designation(s):

ARRIEL 2 engines

Effective Date: 31 March 2016

TCDS Number(s): EASA.E.001

Foreign AD: Not applicable

Supersedure: This AD supersedes EASA AD 2015-0162 dated 06 August 2015.

ATA 72 – Engine – Accessory Gear Box Module M01 – Inspection / Replacement

Manufacturer(s):

Turboméca S.A.

Applicability:

ARRIEL 2B, 2B1, 2B1A, 2B1B, 2C, 2C1, 2C2, 2D, 2E, 2N, 2S1 and 2S2 engines, all serial numbers.

These engines are known to be installed on, but not limited to, Airbus Helicopters AS350B3, 

EC130B4, EC130T2, AS365N3, EC155B and EC155B1 helicopters, Airbus Helicopters Deutschland 

MBB-BK 117 D-2 (EC145T2 or H145) helicopters, Avic international AC311 helicopters, and Sikorsky 

S-76C helicopters.

Reason:

An uncommanded in-flight shut-down (IFSD) of an ARRIEL 2 engine was reported, caused by rupture 

of the 41-tooth gear, which forms part of the bevel gear of the accessory gearbox (module M01). 

The subsequent investigation revealed that wear on the housing of the front bearing of this gear

was a major contributor to this rupture. In addition, the investigation showed that this wear 

mechanism had resulted in positive Spectrometric Oil Analysis (SOA) indications before the event.

This condition, if not detected and corrected, could potentially lead to further cases of IFSD, 

possibly resulting in an emergency landing.
EASA AD No.: 2016-0055

TE.CAP.00110-005 © European Aviation Safety Agency. All rights reserved. ISO9001 Certified.

Proprietary document. Copies are not controlled. Confirm revision status through the EASA-Internet/Intranet.

An agency of the European Union

Page 2 of 4

To address this potentially unsafe condition, Turboméca issued Mandatory Service Bulletin (MSB) 

292 72 2861 to provide SOA check instructions. Consequently, EASA issued AD 2015-0162 to require 

repetitive SOA checks and, depending on the results, replacement of the module M01.

Since that AD was issued, it was determined that wear inspections are necessary, in addition to the 

repetitive SOA checks. Turboméca updated MSB 292 72 2861 to add instructions to accomplish this 

inspection. 

For the reasons described above, this AD partially retains the requirements of EASA AD 2015-0162, 

which is superseded, and requires accomplishment of wear inspection, and, depending on the 

results, replacement of the module M01.

Required Action(s) and Compliance Time(s):

Required as indicated, unless accomplished previously:

(1) Within the compliance time specified in Table 1 of this AD, perform a visual inspection in 

accordance with the instructions of Turboméca MSB 292 72 2861 to identify if a machined front 

casing Part Number (P/N) 0292120650 is installed on that engine.

SOA Checks:

(2) For engines equipped with a module M01 fitted with a machined front casing P/N 0292120650 

(as identified in Turboméca MSB 292 72 2861), within the threshold specified in Table 1 of this 

AD, and, thereafter, at intervals not to exceed 100 EH (see Notes 1 and 2 of this AD), 

accomplish a SOA check in accordance with the instructions of Turboméca MSB 292 72 2861.

Table 1 – Initial SOA check

Engine Hours (EH) accumulated by the Module 

M01 (since first installation on an engine or 

since last overhaul) on 20 August 2015 [the 

effective date of EASA AD 2015-0162]

Threshold

Less than 800 EH Before exceeding 850 EH since first 

installation of the Module M01 on an 

engine, or since last Module M01 

overhaul, as applicable

800 EH or more, or EH not known Within 50 EH after 20 August 2015 [the 

effective date of EASA AD 2015-0162]

Note 1: A non-cumulative tolerance of 10% EH may be applied to the compliance times specified in 

this AD for repetitive inspections, to allow synchronization of the required inspections with other 

maintenance tasks for which a non-cumulative tolerance is already granted in the applicable EMM. 

The 10% EH tolerance does not apply to the initial SOA check and wear inspection.

Note 2: Engine operation could be continued pending oil analysis result within the limit of SOA 

periodicity of 100 EH (see Note 1 of this AD), starting from the oil sampling action.
EASA AD No.: 2016-0055

TE.CAP.00110-005 © European Aviation Safety Agency. All rights reserved. ISO9001 Certified.

Proprietary document. Copies are not controlled. Confirm revision status through the EASA-Internet/Intranet.

An agency of the European Union

Page 3 of 4

Wear Inspection:

(3) For engines equipped with a module M01 fitted with a machined front casing P/N 0292120650 

(as identified in Turboméca MSB 292 72 2861), within the threshold specified in Table 2 of this 

AD, and, thereafter, at intervals not to exceed the values specified in Table 3 of this AD (see 

Note 1 of this AD), accomplish a wear inspection in accordance with the instructions of 

Turboméca MSB 292 72 2861 version B.

Table 2 – Initial Wear Inspection

EH accumulated by the Module M01 (since first 

installation on an engine or since last overhaul)

on the effective date of this AD

Compliance Time

Less than 800 EH Before exceeding 850 EH since first 

installation of the Module M01 on an 

engine, or since last Module M01 

overhaul, as applicable

800 EH or more, or EH not known Within 50 EH or 30 days, whichever 

occurs first after the effective date of 

this AD

Table 3 – Wear Inspection Interval

Engine Models Interval (see Note 1 of this AD)

ARRIEL 2B, 2B1, 2B1A, 2C, 2C1, 2C2, 2D, 2S1

and 2S2 600 EH

ARRIEL 2E and 2N 800 EH

Corrective Actions:

(4) If, during any SOA check accomplished from the effective date of this AD, as required by 

paragraph (2) of this AD, the aluminium concentration is 0.8 ppm or more, within 20 EH after 

that SOA check, accomplish a wear inspection in accordance with the instructions of Turboméca 

MSB 292 72 2861 version B.

(5) If, during the last SOA check on an engine accomplished before the effective date of this AD, as 

required by paragraph (2) of this AD, the aluminium concentration was 0.8 ppm or more, within 

50 EH after that SOA check, or within 20 EH after the effective date of this AD, whichever occurs 

first, accomplish a wear inspection on that engine in accordance with the instructions of 

Turboméca MSB 292 72 2861 version B.

(6) If, during any wear inspection, as required by paragraph (3), (4) or (5) of this AD, as applicable, 

wear exceeding 0.15 millimetres (mm) is found, within the compliance time specified in Table 4 

of this AD, as applicable, depending on the wear results and where the inspection was 

accomplished, replace the module M01 with a serviceable module M01 (refer to paragraph (8) 

of this AD), in accordance with the instructions of Turboméca MSB 292 72 2861 version B.
EASA AD No.: 2016-0055

TE.CAP.00110-005 © European Aviation Safety Agency. All rights reserved. ISO9001 Certified.

Proprietary document. Copies are not controlled. Confirm revision status through the EASA-Internet/Intranet.

An agency of the European Union

Page 4 of 4

Table 4 – Module 01 Replacement (after finding wear)

Wear (W) Found

[in mm]

Wear Inspection accomplished 

while engine installed on aircraft

Wear Inspection accomplished 

in- shop

0.15 < W ≤ 0.30 Within 200 EH

Before release to service of the 

engine 0.30 < W ≤ 0.40 Within 25 EH

W > 0.40 Before next flight

(7) For the purpose of this AD, a serviceable module M01 is either a module M01 fitted with a

machined front casing P/N 0292120650, that is subjected to SOA checks in accordance with 

paragraph (2) and (3) of this AD, or a module M01 fitted with a cast front casing P/N 

0292127020.

Parts Installation:

(8) From the effective date of this AD, it is allowed to install a module M01 fitted with a machined 

front casing P/N 0292120650 on an engine, provided that, following installation, the engine is 

subjected to SOA checks and wear inspections as required by paragraphs (2) and (3) of this AD.

Ref. Publications:

Turboméca MSB 292 72 2861 version A dated 24 April 2015, version B dated 02 February 2016, 

version C dated 11 March 2016.

The use of later approved revisions of this document 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. Based on the required actions and the compliance time, EASA have decided to issue a Final AD 

with Request for Comments, postponing the public consultation process until after publication.

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

Certification Directorate. 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 representative

(refer to http://www.turbomeca-support.com).