AD/BEA 121/8 Amdt 4 Rudder Control Torque Tubes (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/BEA 121/8 Amdt 3 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.

Beagle B121 (Pup) Series Aeroplanes

AD/BEA 121/8 Amdt 4 Rudder Control Torque Tubes 13/2005

Applicability:

All Model Beagle B.121 series aircraft.

Requirement:

Inspect the rudder torque tube assemblies in accordance with de Havilland Support Ltd Service Bulletin B121/65 Issue 2, or later CAA approved revision.

Cracked rudder torque tube assemblies must be replaced before further flight.

Note:  UK CAA AD G-2005-0030 refers.

Compliance:

Within 100 hours time in service since the last inspection performed in accordance with the previous issue of this Directive.  Inspect thereafter at intervals not to exceed 100 hours time in service.

This Amendment becomes effective on 22 December 2005.

Background:

The Type Certificate Holder has received several reports of failed rudder torque tube assemblies.  The recent failures occurred in service after inspections performed in accordance with the previous issue of the Requirement document.  In the event of such failures, loss of directional control through both the rudder and nosewheel steering may occur.  Reports were also received of loose rivets attaching the inboard anchor assembly to the starboard torque tube.  This Directive mandates revised detailed repetitive inspection of the torque tube assemblies.

David Villiers
Delegate of the Civil Aviation Safety Authority

11 November 2005