EASA AD No.: 2015-0175

TE.CAP.00110-004 © 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.: 2015-0175

Date: 24 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 accordance 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 operate 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) exemption].

Design Approval Holder’s Name:

TURBOMECA

Type/Model designation(s):

ARRIEL 1E2 engines

TCDS Number: EASA.E.073

Foreign AD: Not applicable

Supersedure: None

ATA 77 Engine Indicating – Tachometer Boxes – Replacement

Manufacturer(s): Turbomeca

Applicability: ARRIEL 1E2 engines, all serial numbers.

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

Helicopters Deutschland (formerly Eurocopter Deutschland) MBB-BK117-C1 

and MBB-BK117-C2 helicopters.

Reason: There have been reports of Arriel 1E2 engines having experienced an 

uncommanded in-flight shut-down (IFSD) due to an untimely activation of the 

tachometer box shut-off system which was activated by the power turbine 

monitoring function of the tachometer box.

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

possibly resulting in a forced landing.

To address this potential unsafe condition, Turbomeca developed modifications 

(TU369 and TU371) of the tachometer box consisting in the power turbine 

monitoring function inhibition. In addition, Turbomeca issued Mandatory Service 

Bulletin (MSB) 292 77 0844 version B to provide instructions for the 

replacement of the affected tachometer box.

For the reasons described above, this AD requires replacement of the affected 

tachometer boxes.

Effective Date: 07 September 2015
EASA AD No.: 2015-0175

TE.CAP.00110-004 © European Aviation Safety Agency. All rights reserved. 2/2

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

Required Action(s) 

and Compliance

Time(s):

Required as indicated, unless accomplished previously:

Note 1: For the purpose of this AD, an affected engine is an engine installed on 

position #1 (left hand engine position) and is connected to an affected 

tachometer box with a Part Number (P/N) and a Serial Number (S/N) listed in 

Table 1 of this AD.

(1) Within 1 600 flight hours after the effective date of this AD, replace the

affected tachometer box (as listed by P/N and S/N in Table 1 of this AD)

connected to an affected engine with a serviceable unit, in accordance with 

the instructions of Turbomeca MSB 292 77 0844 version B.

Note 2: For the purpose of this AD, a serviceable tachometer box is a unit that 

is not an affected tachometer box as identified in Table 1 of this AD.

Table 1 – Affected tachometer boxes

P/N S/N

9580116170

All

9580116260

9580116900

9580117110

9580117550 All, except S/N 1500EL (see Note 3 of 

this AD) and higher

Note 3: P/N 9580117550 with S/N suffix different than “EL” or without suffix is 

affected by this AD (example: S/N 6091GA, S/N 1713).

(2) Replacement of an affected tachometer box, before the effective date of 

this AD in accordance with the instructions of Turbomeca MSB 292 77 

0844 version A, is acceptable to comply with the requirements of 

paragraph (1) of this AD.

(3) From the effective date of this AD, it is allowed to install a tachometer box 

on an affected engine, provided this unit is a serviceable part as defined in 

Note 2 of this AD.

Ref. Publications: Turbomeca MSB 292 77 0844 version A dated 04 March 2015 or version B 

dated 06 July 2015.

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. This AD was posted on 23 July 2015 as PAD 15-096 for consultation until 

20 August 2015. No comments were received during the consultation 

period.

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:

Turbomeca, 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