INVESTIGATORS may never know what caused a glider crash which killed a former Dalby motel owner.

The problem is due to the extent of the damage at the site.

Simon Brown, who had moved to Victoria, died on impact when his Jonker Sailplanes CC JS1C craft crash landed in a Boggabilla paddock on October 9 last year - the first day of competition at the national championships.

A micro-SD card inside the onboard avionics unit was retrieved from the wreckage which lead investigation agency, the Gliding Federation of Australia, hoped would shed light on what caused the crash.

The Australian Transport Safety Bureau was asked to download the information which can track wind speed, altitude and other data.

"The device was badly damaged, with damage to the internal electronic circuit board," an ATSB report said.

"The ATSB was unable to recover any data.''

Mr Brown, 75, was an experienced glider pilot and a member of the Gliding Club of Victoria who was well-known in the sporting industry.

Witnesses told investigators Mr Brown had been airborne a short time before the glider spiralled down and crashed into the ground.

Emergency responders described it as one of the worst crash scenes they had seen in their careers.

The GFA is compiling a report which will be delivered to the coroner investigating the crash, but warned they may "never know what happened".

"The craft was so badly damaged it may never be clear," an investigator said.

"Even if we had that data it may not be clear, so we will be relying on witnesses.

"It was a very short flight."

The GFA is awaiting pathology results as part of the ongoing investigation.