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Final Report

Summary

What happened

On 16 December 2013, at about 1215 Eastern Standard Time, a de Havilland DH82A (Tiger Moth) aircraft, registered VH-TSG, took off from the operator’s airstrip at Pimpama, Queensland with a pilot and passenger on board. The purpose of the flight was to conduct a commercial joy flight in the Gold Coast area. At about 1224, 1 minute after the pilot commenced aerobatics, the left wings failed and the aircraft descended steeply; impacting the water about 300 m from the eastern shoreline of South Stradbroke Island. The aircraft was destroyed and the two occupants were fatally injured.

What the ATSB found

The ATSB found that both of the aircraft’s fuselage lateral tie rods, which assist in transferring flight loads through the fuselage, had fractured. The location of the fracture coincided with areas of pre-existing fatigue cracking in the threaded sections of the rods, near the join with the left wing. The tie rods fractured during an aerobatic manoeuvre, resulting in the left lower wing separating from the aircraft and subsequent in-flight break-up. The ATSB also found that the tie rods were aftermarket parts manufactured under an Australian Parts Manufacturer Approval (APMA). In this respect, safety issues were identified in areas of the tie rods’ design and manufacture, as well as in the supporting regulatory approval processes. Safety issues were also identified in the maintenance and operation of the aircraft.

What's been done as a result

The ATSB consulted with the Type Design Organisation, regulators and investigation authorities from Australia, New Zealand and the United Kingdom about the failure of the APMA tie rods, which occurred well before the published retirement life for Tiger Moth tie rods. In response, the United Kingdom Civil Aviation Authority issued an airworthiness directive on 21 March 2014 that mandated the removal from service of all tie rods produced by the same Australian manufacturer. The airworthiness directive was subsequently also mandated by the Australian Civil Aviation Safety Authority and the New Zealand Civil Aviation Authority. Significant additional safety action is proposed by the Type Design Organisation to further enhance the safety of all Tiger Moth operations. In addition, the ATSB has issued a safety recommendation to the Civil Aviation Safety Authority to take action to provide assurance that over 1,000 other parts approved for APMA at about the same time as the tie rods were appropriately considered before approval.

Safety message

This accident emphasises the need for the full consideration of a part’s service history when redesigning and manufacturing parts critical to the structural integrity of the aircraft. It also shows the important role of the regulator in ensuring that parts approved under an APMA have been fully considered and shown to comply with the design requirements. Further, in the context of maintenance, it shows the importance of utilising genuine or approved substitute aircraft parts that are suitable for purpose, especially in sections of the aircraft that are critical to flight.

In addition, the ATSB cautions commercial vintage aircraft operators about the risks associated with aircraft age and the importance of understanding the originally-intended use of the design before commencing their operations.

 Tiger Moth aircraft VH-TSG

VH-TSG

Source: David Welch, Air-Britain Photographic Images Collection

The occurrence

Context

Safety analysis

Findings

Safety issues and actions

Sources and submissions

Appendices

 
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