The pilot of the single-seater plane died in the crash
A 50-year-old man from Spalding died when the privately owned plane he was piloting crashed in Lincolnshire.
The single-seater aircraft came down in a field shortly after taking off from Fenland Airfield in Holbeach St John, near Spalding, at about 1100 GMT.
Air Accident Investigation Branch (AAIB) inspector Tim Atkinson said he would be speaking to witnesses as part of an investigation.
He said it was too early to speculate about what might have caused the crash.
The inspector added the history of the aircraft and the pilot would form part of the inquiry.
"I believe the accident happened shortly after take-off," he said on Saturday afternoon.
He said they would now be gathering evidence.
"We will be analysing that evidence to try and find out why it has happened and, if possible, making safety recommendations to try and prevent a similar accident happening."
Insp Andy Ham from Lincolnshire Police earlier said there was "no reason to suggest any suspicious circumstances".
"The initial indication is that an aeroplane with one occupant took off from Fenland Airfield and shortly after taking off, it got into some difficulty and issued a Mayday," he said.
"Without any further communication, the plane came back down to Fenland Airfield and unfortunately crashed."
A spokesman from Fenland Airfield said: "It is a tragedy and we are doing what we can."