In May 2007, the Australian Government signed a contract to acquire 24 F/A-18F Super Hornets for the Royal Australian Air Force, as an interim replacement for the aging F-111. The order resulted from concern that the F-35 Joint Strike Fighter (JSF) would not be operational by the time the F-111s were retired. The RAAF's first five Super Hornets arrived at their home base, RAAF Base Amberley in Queensland, on March 26th 2010, with a second batch of six arriving on July 6th and a third batch of four aircraft arriving on December 7th. The remaining aircraft (Serial numbers A44-216 - A44-224) are planned for delivery in 2011.