In the late 1980s, Hadfield attended the US Air Force Test Pilot School at Edwards Air Force Base and served as an exchange officer with the US Navy at Strike Test Directorate at the Patuxent River Naval Air Station. His accomplishments from 1989 to 1992 included testing the McDonnell Douglas F/A-18 Hornet and LTV A-7 Corsair II aircraft; performing research work with NASA on pitch control margin simulation and flight; completing the first military flight of F/A-18 enhanced performance engines; piloting the first flight test of the National Aerospace Plane external burning hydrogen propulsion engine; developing a new handling qualities rating scale for high angle-of-attack test; and participating in the F/A-18 out-of-control recovery test program.