A 60-year-old Leongatha man died when the Piper Pawnee agricultural aircraft in which he was the sole occupant went down in February.
In its preliminary report released on Tuesday, the Australian Transport Safety Bureau said the aircraft was flown from Leongatha to a private landing area 25 kilometres north of Seaview.
It was then to be used for aerial spreading of superphosphate pellets.
Witnesses and video show the plane take-off and briefly become airborne at the end of the strip, where the terrain dropped away.
The aircraft's left wing then struck trees and the aircraft rolled to the left and then hit the ground, destroying the plane.
ATSB Director Transport Safety Mike Walker said an on-scene examination of the crash site showed no signs of defects before the incident and the weather at the time was fine.
He noted that while the aircraft's hopper was capable of carrying about 700kg of pellets for aerial application, its maximum allowed load was 544kg.
"The exact volume or weight of superphosphate loaded into the aircraft prior to the accident could not be determined, and the loader driver could not later recall how much superphosphate had been loaded," Dr Walker said.
"Consideration of aircraft weight and balance and take-off performance is a central theme of this investigation."
The investigation is continuing and will include examination of pilot and aircraft records and further analysis of witness video and the aircraft's GPS data.
A final report will be released at the end of the investigation.
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