A light plane crash which killed two people and sparked a grass fire in southwest Sydney will be examined by the national transport safety agency.
The Australian Transport Safety Bureau (ATSB) has launched an investigation into the circumstances surrounding the Boxing Day crash.
Emergency services responded to the fire at Appin about 3pm on Monday where two bodies were found in the aircraft wreckage.
The two victims are yet to be formally identified.
ATSB Chief Commissioner Angus Mitchell said a team of transport safety officers from Canberra and Brisbane had begun on-site investigations on Monday afternoon.
"The initial ATSB safety investigation will include an examination of the wreckage, assessment of aircraft and pilot records, weather information and any available recorded data," he said.
The chief commissioner asked anyone who may have seen the aircraft in flight or had any footage to contact the agency via the website.
A preliminary report is expected in about eight weeks time.