AD/EC 225/10 Rotor Flight Controls Tail Servo-control (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(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 EC 225 Series Helicopters

AD/EC 225/10 Rotor Flight Controls - Tail Servo-control 11/2008

Applicability:

Eurocopter EC 225LP helicopters fitted with tail servo-control P/N SC7252 before amendment A.

Requirement:

1.    Apply the tightening torque in specified in paragraph 2.B.2. of EUROCOPTER EC 225 Alert Service Bulletin (ASB) No. 67A001 or later NAA approved revision.

2.    Manually check for absence of axial play of the two control levers along the distributor shafts of the tail servo-control, in accordance with paragraph 2.B.3. of ASB No. 67A001 or later NAA approved revision.

3.    In case of play, replace the servo-control in accordance with paragraph 2.B.3. of the ASB 67A001 or later NAA approved revision.

Note:  DGAC AD F-2005-138 dated 3 August 2005 refers.

Compliance:

For Requirement 1 - No later than within 110 flying hours after the effective date of this AD.

For Tail Servo Controls held as spares - Before installation on a helicopter.

For Requirement 2 - No later than within a period of 135 to 165 flying hours following completion of Requirement 1 of this AD.

For Requirement 3 - Before further flight.

This Airworthiness Directive becomes effective on 23 October 2008.

Background:

This AD is in response to a case of control lever slipping along the shaft of one of the distributors, discovered upon removal of a tail servo-control for repair on an AS 332 helicopter.

The control lever could have totally separated from the distributor shaft, which could lead to the loss of the tail rotor control.

The attaching principle of the control lever/shaft connection of tail servo-control distributors on AS 332 and EC 225 is identical.

Consequently, the purpose of this AD is to eliminate the risk of disconnection of tail servo-control distributor control levers.

Charles Lenarcic
Delegate of the Civil Aviation Safety Authority

8 September 2008