Airworthiness Directive

ID: AD/AS 355/68
Source: CASA




'TRW-SAMM' Main Servocontrols

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under
subregulation 39.1 (1) of CAR 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 355/68 “TRW-SAMM” Main Servocontrols 10/2002

AS 355 helicopters version F, F1, F2, and N equipped with “TRW-SAMM’ main
servocontrols Part Number (P/N) SC 8042 or SC 8043 which underwent their last
complete overhaul or repair since overhaul at “HAWKER PACIFIC AEROSPACE’,
USA before March 1 2002.

Remove the servocontrols and return them to “HAWKER PACIFIC AEROSPACE”
for a check of the thread condition and application torque as required in Eurocopter
AS 355 Alert Telex No. 67.00.23.

Note: DGAC 2002-315-069(A).

1. For servocontrols held as spares; prior to fitment to an aircraft.

2. For servocontrols that have been in service for less than 1000 flight hours since
overhaul; within 550 flight hours or 3 October 2003, whichever comes first.

3. For servocontrols that have been in service between 1000 and 1300 flight hours
since overhaul; prior to 1550 flight hours or 3 July 2003, whichever comes first.

4. For servocontrols that have been in service for more than 1300 flight hours since
overhaul; within 250 flight hours or 3 March 2003 whichever comes first.

This Airworthiness Directive becomes effective on 3 October 2002.

An incorrect torque loading was found to have been applied to the end fitting that
attaches the servocontrol cylinder to the upper ball end fitting. The incorrect torque
may lead to failure of the threads on the fitting, leading to separation of the upper-end
fitting and result in loss of control of the helicopter.

James Coyne
Delegate of the Civil Aviation Safety Authority

23 August 2002

The above AD is notified in the Commonwealth of Australia Gazette on 11 September 2002.

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This is a partial extract of the full document - please refer to the actual report for full information.
Sources as credited.