Introduction The F-111 is a dual-seat, supersonic, variable geometry wing strike aircraft that has enjoyed RAAF and USAF service for the last 30 years. Approximately 550 aircraft were built between 1964 and 1973, with model variants from F-111A to F-111F. RAAF operations commenced in 1973 with the purchase of 24 F-111C aircraft and are planned to continue to 2020. Due to the age of the fleet and its changed circumstances ...