The Lockheed AP-3C Orion is a variant of the P-3 Orion used by the Royal Australian Air Force (RAAF) for tasks such as naval fleet support, maritime surveillance, search and survivor supply and anti-surface and anti-submarine warfare. The 18 AP-3C Orions were upgraded from P-3Cs between 1997 and 2005, with the program taking three years longer than expected due to systems integration problems. All 18 AP-3C Orions are operated by No. 92 Wing which is based at RAAF Base Edinburgh in South Australia. Aircraft from the wing have seen service as part of Australian Defence Force operations in Australia, South East Asia and the Middle East.