International kit-built plane operators have been given a safety warning after an investigation into a fatal crash north of Brisbane found the accident was caused by the failure of two wing bolts.
The Australian Transport Safety Bureau (ATSB) launched the probe after a pilot died when his "home built" Acroduster crashed on mudflats near Bribie Island on August 18.
The man flying the biplane, which is typically designed for aerobatics, was the only person on board.
ATSB chief commissioner Angus Mitchell says a preliminary probe found bolts that attach the upper wings had cracked under fatigue.
"It was evident to our investigators once they had arrived on site that the aircraft had sustained an in-flight break-up, with the wreckage trail distributed over a distance of about 2.4km," Mr Mitchell said in a statement on Wednesday.
"Preliminary examination of the main wreckage revealed that two of the eye bolts that attached the upper wings to their supporting struts had failed due to fatigue cracking.
A Safety Advisory Notice had been issued to the only other owner of an Acroduster in Australia as well as their US counterparts.
While unsure how many aircraft would be affected overall by the notice, the ATSB said about 130 Acrodusters had been built since the plans were made available in the early 1970s.
The Acroduster involved in the crash had been built in the US from plans supplied in 1976 and first flew in 1981.
After being shipped to Australia in 2003, it had accumulated 717 flight hours at the time of the accident.
"While our investigation is ongoing, the Safety Advisory Notice serves to inform operators of this (aircraft) type internationally of this discovery so that they can take appropriate action to ensure that their aircraft remain airworthy," Mr Mitchell said.
The ATSB will release a final report on the crash once the investigation is completed.