1AD/AC-SNOW/16 Amdt 1 - Rudder Horn Balance/Leading Edge Intersection

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Ayres Thrush (Snow) Commander Series Aeroplanes

AD/AC-SNOW/16

Amdt 1

Rudder Horn Balance/Leading Edge Intersection

10/88

Applicability: All models S-2D and S-2R modified in accordance with Part 2 of AD/AC-SNOW/12. Requirement: 1. Remove the rudder from the aircraft.

2. Strip the fabric and dope from the intersection of the horn balance and the rudder leading edge in the region of the top hinge.

3. Inspect the intersection for cracking using a 10x glass paying particular attention to the hinge reinforcement weld edge.

4. If cracking is found repairs are to be carried out in accordance with AC 43.13 or a scheme approved by the Authority.

Note: Findings for all aircraft are to be reported to local airworthiness offices of the Authority.

Compliance: Within 10 hours’ time in service after 8 February 1988.

Background: The initial issue of the Directive was a one-time inspection pending an accident investigation for any further action. As a result of that accident investigation the Background is amended to note that the failure of the rudder structure in the area of the hinge modification has been attributed to undiscovered/unrectified cracking present at the time of the AD/AC-SNOW/12 modification. The undiscovered cracking continued to grow until rudder structural failure was inevitable.