AD/Ecureuil/95 Amdt 1 Engine Controls Twist Grip Solenoid (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/ECUREUIL/95 and issues the following AD under subregulation 39.001(1) of CASR 1998.  The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Eurocopter AS 350 (Ecureuil) Series Helicopters

AD/ECUREUIL/95 Amdt 1 Engine Controls - Twist Grip Solenoid 9/2006 TX

Applicability:	AS 350 B3 helicopters fitted with twist grip post MOD 073084 and not modified per MOD 073222 (new solenoid).
Note 1:  Helicopters modified per MOD 073261, which is only embodied on helicopters equipped with Arriel 2B1 engine, are not affected by this Directive.
Requirement:	1.    Remove the Before Flight Check procedures inserted into Section 4 - Normal Procedures of the Aircraft Flight Manual (AFM) in accordance with the Original Issue of this Directive.
2.    Operate the helicopter in accordance with Eurocopter Alert Service Bulletin (ASB) AS 350 05.00.44 issued 23 June 2006.
3.    Replace the solenoid in accordance with paragraph 2.B.3 of the ASB AS 350 05.00.44 if, at any time, the operating time of the solenoid (AUTO/MAN governing mode selector set to MAN) exceeds 15 consecutive minutes or if a waiting time of at least 15 minutes was not observed between two consecutive operations (even if the solenoid has only operated for a few seconds).
Note 2:  EASA Emergency AD 2006-0183-E refers.
Compliance:	For Requirement 1 - Before 12 July 2006.
For Requirement 2 - With effect from 12 July 2006 until MOD 07322 is incorporated.
For Requirement 3 - Before further flight, following each occasion the operating times are exceeded, until MOD 07322 is incorporated.
This Amendment becomes effective on 10 July 2006.
Background:	The original issue of this Airworthiness Directive followed advice from the Direction Générale de l’Aviation Civile of France that during prolonged application of electrical power to the twist grip solenoid resulted in locking pin seizure due to overheating of the solenoid.  The seizure could result in loss of the emergency governing function.

The original issue of this Airworthiness Directive required a temporary addition to the AFM Normal procedures until a modification is developed.

This Amendment follows further advice from the European Aviation Safety Agency (EASA) that consecutive operation of the solenoid should be limited and that a minimum waiting period between two operations of the solenoid should also be observed.  The Amendment removes the AFM supplement inserted in accordance with the original Directive, requires the helicopter be operated in accordance with the Eurocopter ASB and requires that the solenoid be replaced if certain operating times of are exceeded.

The original issue of this Airworthiness Directive became effective on 7 April 2004.

James Coyne
Delegate of the Civil Aviation Safety Authority

7 July 2006