Accident caused by the crew "initiating and continuing a descent in IMC below the authorized altitude without visual contact with the runway environment."
Learjet conducted an “unexpected maneuver,” continuing a left-hand turn with an “excessive bank angle despite the loss of visual contact" with the fighter.
Purwin, 53, founded the company that became Helinet in 1987 and was considered one of Hollywood’s top television and film helicopter and fixed-wing pilots.