AD/INST/20 Sep 2 Automatic Pilot Trim Servomotor Venting Modification Cancelled (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/INST/20.

Instruments and Automatic Pilots

AD/INST/20 Sep 2 Automatic Pilot Trim
Servomotor Venting - Modification 3/2009

Requirement:

CANCELLED.

This AD is cancelled on 12 March 2009.

Background:

This unique Australian AD raised in 1976 against Smiths Industries Ltd Service Bulletin (SB) SB 22-918 recommending a modification to the servomotor by introducing two vent holes in the armature assembly of the clutch assembly to assist the clutch to disengage when power supplies were removed.

Compliance was before installation in an aircraft following the next reconditioning or repair performed after 30 July 1976, whichever occurs first.

Given the extended time this AD has been promulgated it is considered that the affected servomotors would have been modified by now, therefore this AD is considered to be no longer required.

James Coyne
Delegate of the Civil Aviation Safety Authority

27 January 2009