 In 2007, the Australian government decided to retire the F-111s by 2010, and acquire 24 Boeing F/A-18F Super Hornets as an interim replacement, pending the arrival of the Lockheed Martin F-35 Lightning then being developed.The F-111 fleet was considered to be at risk due to fatigue, and too expensive to operate as each aircraft required 180 hours of maintenance for every hour of flying time.No.