Stunt caused plane to break up over Qld

An aerobatic stunt contributed to a biplane crash that killed a newly wed pilot and a French woman near Queensland's South Stradbroke Island.

The Air Transport Safety Bureau report into the accident, released on Thursday, found the 1930s Tiger Moth broke up during a stunt near the island in December 2013.

It found that during an aerobatic manoeuvre crucial tie rods, which transfer flight loads throughout the fuselage, had snapped.

The bureau says the fracture occurred near pre-existing fatigue cracking in 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 report said.

It said the tie rods were replacement parts based on the design of the original parts, but neither the design engineer nor the Civil Aviation Safety Authority knew the original parts actually had a life limitation and were susceptible to fatigue cracking.

The ATSB also said although a number of aerobatic manoeuvres were permitted in Tiger Moth aircraft, there was no limitation on the amount of aerobatic operations considered to be safe.

"As a result, operators may be unaware that a high aerobatic usage may exceed the original design assumptions for the aircraft," the report said.

The plane broke up when it hit the water about 400 metres offshore, leaving large pieces of debris bobbing in the water.

Some reports have said the plane speared into the water in an almost vertical position.

In his last radio communication, the pilot said: "Conducting aerobatics over 3500 feet", The Courier-Mail reported at the time.

That was the last time anyone heard from the 26-year-old newly-wed man, who worked for Gold Coast-based Tiger Moth Joy Rides.

His passenger was a French woman, the newspaper said.