EASA AD No.: 2011-0033 

EASA Form 110 Page 1/2 

EASA AIRWORTHINESS DIRECTIVE 

AD No.: 2011-0033 

Date: 01 March 2011 

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 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]. 

Type Approval Holder’s Name : 

EUROCOPTER 

Type/Model designation(s) : 

AS350 Helicopters 

TCDS Number : EASA R.008 

Foreign AD : Not applicable 

Supersedure : None 

ATA 29 Hydraulic Power – Forward Hydraulic Servo Control Hoses / 

Protection Installation 

Manufacturer(s): Eurocopter (formerly Eurocopter France, Aerospatiale) 

Applicability: AS 350 B, BA, BB, D, B1, B2, and B3 helicopters, all serial numbers, with a 

single hydraulic power system and the following forward (pitch) servo-control 

hydraulic hoses installed: 

- P/N 704A34-412-033 (other reference MP/N 675-102-05-01); 

- P/N 704A34-412-035 (other reference MP/N 675-102-06-01). 

Reason: An in-flight fire in the main gearbox compartment occurred on an AS350B2 

helicopter. The fire was caused by ignition of hydraulic fluid leaking from a 

hydraulic hose, which had been damaged following an electrical fault in a 

circuit located in the compartment that is not fire protected. 

An in-flight fire in the main gearbox compartment during a continued flight, 

when undetected or if a landing could not be performed immediately, can 

result in loss of hydraulics, possible shut down of the engine because of fire 

effects and damage to the Main Rotor (MR) control system. This condition, if 

not prevented, could lead to loss of MR control, potential power loss, 

structural damage and propagation of fire into the cabin or other 

compartments, consequently with loss of control of the helicopter and 

possible injury of the occupants. 

For the reasons described above, this AD requires installation of protection 

sleeves on hydraulic hoses as a final solution. 

Effective Date: 15 March 2011 
EASA AD No.: 2011-0033 

EASA Form 110 Page 2/2 

Required Action(s) 

and Compliance 

Time(s): 

Required as indicated, unless accomplished previously: 

(1) Within 30 days after the effective date of this AD install protection sleeves 

P/N 706A34-402-225 and 706A34-402-224 on hydraulic hoses P/N 

704A34-412-033 and 704A34-412-035 respectively in accordance with the 

instructions of paragraph 2.B.2 of the Alert Service Bulletin (ASB) No. 

29.00.13. 

(2) Helicopters equipped in production with modification 074238 are in 

compliance with the requirements of paragraph (1) of this AD. 

(3) After the effective date of this AD, do not install on any helicopter hydraulic 

hoses P/N 704A34-412-033 and 704A34-412-035 without protection 

sleeves P/N 706A34-402-225 and 706A34-402-224 respectively.

Ref. Publications: EUROCOPTER AS350 B, BA, BB, D, B1, B2, B3 ASB No. 29.00.13 

Revision 0, dated 26 July 2010 or later approved revisions. 

Remarks : 1. If requested and appropriately substantiated, EASA can accept 

Alternative Methods of Compliance for this AD. 

2. The required actions and the risk allowance have granted the issuance of 

a Final AD with Request for Comments, postponing the public 

consultation process after publication. 

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 question concerning the technical content of the requirements in 

this AD, please contact: EUROCOPTER (STDI) - Aéroport de Marseille 

Provence 13725 Marignane Cedex - France. Tel: +33 (0) 4 42 85 97 97 - 

Fax: +33 (0) 4 42 85 99 66. 

E-mail: Directive.technical-support@eurocopter.com