AD/As 355/88 Amdt 1 Cabin Vibration Damper Assembly (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 355/88 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 355/88 Amdt 1 Cabin Vibration Damper Assembly 12/2006

Applicability:

1.    Eurocopter AS 355 E, F, F1, F2 and N helicopters fitted with:

a.     a cabin vibration damper assembly installed on the right hand (RH) side of the helicopter; and

b.    an automatic flight control system.

Requirement:

1.    Visually check the visible areas of the blade of the vibration damper assembly, installed on the RH side of the helicopter, for cracks, in accordance with paragraph 2.B.1 of Eurocopter AS 355 Alert Service Bulletin (ASB) No. 05.00.46 or any later EASA approved revisions.

2.    If a crack is found, remove the RH vibration damper assembly, replace the cracked blade and re-install the vibration damper assembly fitted with a new blade, and adjust the vibration damper in accordance with paragraph 2.B.1 of Eurocopter AS 355 Alert Service Bulletin (ASB) No. 05.00.46 or any later EASA approved revisions.

3.    For helicopters modified per MODs 072262, 071543 and OP1055 install a vibration damper/casing assembly on the RH side of the helicopter, in accordance with paragraph 2 of Eurocopter ASB No. 53.00.22 or any subsequent EASA approved revisions, as is applicable.

Terminating Action.

Compliance with Requirements 2 provides terminating action to the repetitive inspections detailed in Requirement 1 of this AD.

Note:  EASA AD 2006-0273 dated 4 September 2006 refers.

Compliance:

1.    Repetitively before the first flight of the day after the effective date of this AD.

2.    Before further flight.

3.    No later than 30 June 2007.

This Amendment becomes effective on 23 November 2006.

Background:

In the event of a failure of the blade of the RH cabin vibration damper assembly, for helicopters fitted with an automatic flight control system, the failed part that remains trapped in the bottom structure lower fairing can interfere with the trim actuator rod which is installed nearby.  Such interference could jam the flight controls.

This amendment introduces a mandatory modification to the vibration damper assembly which terminate the repetitive inspection called up in this AD.

The original issue of this AD became effective 20 June 2005.

James Coyne
Delegate of the Civil Aviation Safety Authority

13 October 2006