EASA AD No : 2008-0170 

EASA Form 110 Page 1/2 

EASA AIRWORTHINESS DIRECTIVE 

AD No.: 2008-0170 

Date: 25 September 2008 

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 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 ensured by accomplishing any applicable ADs. Consequently, no person may 

operate an aircraft to which an Airworthiness Directive applies, except in accordance with the requirements of that Airworthiness 

Directive 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]. 

Type Approval Holder’s Name : 

TURBOMECA 

Type/Model designation(s) : 

ARRIUS 2F turbo-shaft engine 

TCDS Number : France N° M22 

Foreign AD : Not applicable 

Supersedure : None 

ATA 73 Engine Fuel & Control - Lubrication Unit - Modification 

Manufacturer(s): Turbomeca 

Applicability: ARRIUS 2F turbo-shaft engines, all serial numbers, which do not embody 

modification Tf75. 

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

Eurocopter EC120B helicopters. 

Reason: Investigations of incidents which occurred on ARRIUS 2 turboshaft engines 

have revealed the interruption of engine lubrication further to oil passage 

blockage within the lubrication unit check valve. 

This blockage comes from the excessive swelling of the check valve piston 

o-ring. The level of swelling of the o-ring depends on the class of the oil used 

(Standard (STD) or High-Thermal Stability (HTS)) and the engine operating 

time. This phenomenon only affects ARRIUS 2F engines which do not 

embody modification Tf75.

Blockage of check valve may result in a bearing damage caused by a lack of 

lubrication to the bearings which may lead to an uncommanded or 

commanded in-flight shutdown which, on a single-engine helicopter, leads to 

an emergency autorotation landing. 

This Airworthiness Directive is issued to eliminate the possibility of a check 

valve blockage due to an excessive swelling of the check valve piston o-ring, 

by mandating the replacement of the current check valve piston by a check 

valve with seal-free piston.
EASA AD No : 2008-0170 

EASA Form 110 Page 2/2 

Effective Date: 09 October 2008 

Required Action(s) 

and Compliance 

Time(s): 

Required as indicated, unless accomplished previously: 

No later than 31 May 2009, replace check valve piston and remove 

preformed packing in accordance with the instructions specified within 

Turbomeca Service Bulletin n° 319 79 4075.

Ref. Publications: 

TURBOMECA Service Bulletin n° 319 79 4075 

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 12 August 2008 as PAD 08-090 for consultation 

until 29 August 2008. No comments were received during the 

consultation period. 

3. Enquiries regarding this AD should be referred to the Airworthiness 

Directives, Safety Management & Research Section, Certification 

Directorate, EASA. E-mail ADs@easa.europa.eu. 

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

this AD, please contact: 

ARRIUS 2 Customer Support 

TURBOMECA - 40220 Tarnos, France 

FAX + 33 5 59 74 45 15