A popular serviceman from RAF Cottesmore died after he lost control of his car and it veered sharply into the path of an oncoming vehicle.
Kamrul Hassan, 28, who served with the 504 RAF reservist squadron at the former airbase, died as his Ford Focus crossed into the opposite lane on the A6 west of Kettering on the evening of February 23 this year.
He hit an oncoming car driven by Suzanne Jones, of Desborough, leaving her hospitalised for seven months with several broken bones. She is now wheelchair-bound as her feet had to be completely restructured.
Clinton Vickerstaff, of Belper, was driving his car along the road when the accident occurred, and he stopped to help both victims.
He told the inquest in Kettering: “Up ahead, I heard a loud bang and saw a ball of flames shoot up about 50ft high.
“I thought an aircraft had crashed.”
The inquest heard Mr Hassan, of Knox Road, Wellingborough, worked as an IT technician, and was also a Leading Aircraftman reservist squadron.
Collision investigator for Northamptonshire Police Andy Jeavons said excessive speed was likely to be a big factor in causing the crash, but why Mr Hassan veered sharply to the other side of the road was a mystery.
Coroner Anne Pember recorded an accidental death verdict, and said: “I believe the crash was down to driver error and speed played a big factor.”