A helicopter may have struck an eagle shortly before breaking up, crashing and killing the pilot in remote bushland northwest of Sydney, an ongoing investigation says.
The Australian Transport Safety Bureau's (ATSB) preliminary report into the Bell 206L-1 LongRanger helicopter's July 9 crash near Maroota, includes some of the evidence the agency has collected.
"A bird strike which we have identified as being a wedge-tailed eagle has contributed in some way to this accident," ATSB Chief Commissioner Angus Mitchell said on Thursday.
"We have also found that the helicopter sustained an in-flight break-up," he said.
The pilot, a man in his 60s, was on a private flight from Cattai to St Albans when the chopper crashed and was engulfed in flames.
Witnesses described seeing the helicopter begin to bank sharply and pitch upward, while the sound of its rotor changed before the blades detached.
The helicopter was destroyed by fire after impact and the pilot who died was the only person on board.
Parts of the helicopter were littered around the crash scene, some almost 100 metres from the main cockpit.
A wedge-tailed eagle carcass was found near a section of the rotor.
Biological residue found on the exterior of the helicopter was sampled for analysis by the Australian Museum and identified along with the carcass as the eagle.
Analysis and findings will be contained in a final report to be released at a later date.
The ATSB will analyse the recorded flight data and review aircraft documentation and maintenance as well as the pilot's experience and qualifications before releasing its final report.
