Ad/Storch/1 - Elevator Trim Tab Mass Balance (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.

Storch Aviation Slepcev Storch SS4 Series Aeroplanes

AD/STORCH/1 Elevator Trim Tab Mass Balance 11/2006 DM

Applicability:

All Slepcev SS-MK4 aircraft.

Requirement:

Remove the fabric from around the elevator trim tab mass balance arm.  Inspect, using dye penetrant or a microscope, the mass balance attachment to detect any signs of cracking.

If any cracking is detected, the attachment of the mass balance is to be repaired by re-welding.

Compliance:

The initial inspection and, if necessary, repair must be performed before further flight.  Subsequent inspections must be performed at 200 hourly intervals.

This Airworthiness Directive becomes effective on 20 September 2006.

Background:

There have been two reported instances of cracking of the trim tab mass balance.  In one instance the mass balance broke off after cracking progressed through the attachment weld and through the aluminium bracket.

Greg Vaughan
Delegate of the Civil Aviation Safety Authority

15 September 2006