AD/As 355/87 Amdt 1 Untimely Firing of Squibs (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/AS 355/87 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 355 (Twin Ecureuil) Series Helicopters

AD/AS 355/87 Amdt 1 Untimely Firing of Squibs 8/2006 DM

Applicability:	AS 355 E, F, F1, F2 and N helicopters equipped as follows:
Goodrich electric hoists 76370-XXX, (all types of motors) and not modified per MOD 073318 (or per Eurocopter AS 355 Alert Service Bulletin (ASB) 25.00.85 issued 16 November 2005); or
Goodrich electric hoists 76370-XXX, not fitted with the Auxilec motor.
Requirement:	1.    If not previously accomplished, deactivate the squib and affix placards in the cockpit and in the cabin near the hoist operator in accordance with paragraph 2.B. of Eurocopter Alert Telex (AT) 25.00.84 dated 25 May 2005 (Eurocopter AS 355 ASB 25.00.84 issued 16 November 2005).
2.    If not previously accomplished, comply with the operating instructions specified in paragraph 2.D. of AT 25.00.84 (AS 355 ASB 25.00.84).
3.    Comply with the operating instructions specified in paragraph 2.B. of AT 25.00.84 (AS 355 ASB 25.00.84).
4.    Modify the hoist electrical wiring by eliminating the ground from the hoist squib as specified in paragraph 2.B. of AS355 ASB 25.00.85 issued 16 November 2005.
Later revisions of the above service bulletins approved by the European Aviation Safety Agency (EASA) may be utilised for compliance with the applicable requirements of this Directive.
Note:  EASA AD 2006-0164 refers.
Compliance:	For Requirement 1 - Before the next hoisting operation.
For Requirement 2 - Immediately following Requirement 1.
For Requirement 3 - Prior to installing a hoist.

For Requirement 4 - Within 30 days after the effective date of this Directive or before installation of an unmodified hoist on a helicopter.
This Amendment becomes effective on 28 June 2006.
Background:	The French Direction de L’Aviation Civile has advised of the discovery of a potential risk of untimely squib firing which would cause the cable to be cut.  Consequently, the original issue of this Directive required the squib function to be inhibited, the manual cable cutter to be operated and operational procedures to be adapted.
This Amendment, whilst continuing the requirements of the original issue of this Directive restricts the applicability after the embodiment of MOD 073318 and, at the same time renders mandatory the modification on other helicopters.  The Amendment also amends a typographical error in the number of the alert telex.
The original issue of this Directive became effective on 2 June 2005.

James Coyne
Delegate of the Civil Aviation Safety Authority

14 June 2006