The wife of a Queensland gliding instructor flew the tow plane which lifted her husband's aircraft into the air, but then watched in despair as he and his student fatally crashed.
Instructor Jeremy Thompson, 62, and his 60-year-old student Norbert Gross were killed when their 650 kilogram motorless plane crashed into a paddock in the Darling Downs region on Tuesday morning.
Conditions were fine and Gliding Federation of Australia operations executive manager Christopher Thorpe believes the pilot must have suffered a medical event.
"Our preliminary investigation suggests the aircraft was not the problem," Mr Thorpe told AAP.
"The manner in which the aircraft impacted the ground, it can only have been done by deliberate manipulation of the controls or by pilot incapacitation.
"That means the pilot must have suffered a catastrophic medical event.
"It's not your normal accident. Aeroplanes don't normally dive into the ground from 50 feet."
Two GFA investigators were sent to the scene near the Darling Downs Soaring Club to assist forensic police in their investigation and had already spoken to a number of witnesses, Mr Thorpe said.
Mr Gross, from The Whitsundays, had become a member only days before the incident.
Police said in a statement the glider crashed into a field about 30 metres from the runway as the pair was returning from a training flight.
Darling Downs Inspector Stephen Angus told local newspaper the Toowoomba Chronicle Mr Thompson's wife had flown the tow plane.
She landed and was watching on as her husband's aircraft crashed as it came in to land.
