AD/GAF-N22/69 Amdt 6 Ailerons (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/GAF-N22/69 Amdt 5 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.

GAF N22 and N24 Series Aeroplanes

AD/GAF-N22/69 Amdt 6 Ailerons 11/2009

Applicability:

All Model N22 and N24 Series aircraft.

Requirement:

1.    Action in accordance with ASTA Nomad Alert Service Bulletin ANMD-57-18 Issue 1 dated 14 August 2006.

2.    Incorporate ASTA Nomad Alert Service Bulletin ANMD-27-53 dated
20 February 2008.

Incorporation of ANMD-27-53 dated 20 February 2008 cancels the limitations imposed by Alert Service Bulletin ANMD-57-18, and is terminating action for this Airworthiness Directive.

Compliance:

Requirement 1:  Within 50 hours time in service after 26 October 2006 or before
26 November 2006, whichever occurs first.

Requirement 2:  Before 30 June 2010.

The compliance time for Requirement 1 remains unchanged from the previous Amendment of this Airworthiness Directive.

This Amendment becomes effective on 22 October 2009.

Background:

Late in 2002 the manufacturer advised CASA of another Nomad accident which was possibly caused by aileron flutter with the flaps at 38 degrees.  This, along with the other flutter incidents, has resulted in the manufacturer issuing ANMD-57-18 Issue 1 as a precautionary measure while they further investigate the issue.

The manufacturer has now completed their investigation and issued Alert Service Bulletin ANMD-27-53 to modify flap actuation linkages to restore the necessary rigidity to the outboard flap, and hence the aileron.  The unacceptable flexibility of the outboard flap mechanism allows flutter to occur in extreme circumstances.

This amendment mandates Alert Service Bulletin ANMD-27-53, which requires modifications to the aircraft, but terminates the limitations imposed by earlier amendments.

The initial issue of this AD imposed weight and speed restrictions in the flaps extended configuration, and prohibited the use of 38 degrees flap.

Amendments 1 and 2 progressively eased these restrictions as the investigation progressed.

Amendment 4 of this Airworthiness Directive became effective on 12 March 2003.

Amendment 5 mandated Alert Service Bulletin ANMD-57-18 issue 1 dated
14 August 2006.

The original issue of this Airworthiness Directive became effective on
20 September 1994.

David Villiers
Delegate of the Civil Aviation Safety Authority

10 September 2009