Su-27 force is based at Hainan. The island also houses a large signals intelligence facility that tracks civil and military activity in the area and monitors traffic from commercial communications satellites. The United States has long kept the island under surveillance; on May 22, 1951, for example, RAF Spitfire PR Mk 19s out of Hong Kong's Kai Tak Airport flew photo-reconnaissance missions at the behest of U.S. naval intelligence. In the air On April 1, 2001, the EP-3 (BuNo 156511), assigned to Fleet Air Reconnaissance Squadron One (VQ-1, "World Watchers"), had taken off as Mission PR32 from Kadena Air Base in Okinawa, Japan. At about 9:15 a.m. local time, toward the end of the EP-3's six-hour ELINT mission, it was flying at and , on a heading of 110°, about away from the island. Two Chinese J-8s from Hainan's Lingshui airfield approached. One of the J-8s (81192), piloted by Lt. Cdr. Wang Wei, made two close passes to the EP-3. On the third pass, it collided with the larger aircraft. The J-8 broke into two pieces; the EP-3's radome detached completely and its No. 1 (outer left) propeller was damaged severely. Airspeed and altitude data were lost, the aircraft depressurized, and an antenna became wrapped around the tailplane. The J-8's tail fin struck the EP-3's left aileron, forcing it fully upright, and causing the U.S. aircraft to roll to the left at three to four times its normal maximum rate. The impact sent the EP-3 into a 30° dive at a bank angle of 130°, almost inverted. It dropped in 30 seconds, and fell another before the pilot, Lt. Shane Osborn, got the EP-3's wings level and the nose up. In a September 2003 article in Naval Aviation News, Osborn said that once he regained control of the aircraft, he "called for the crew to prepare to bail out". He then managed to control the aircraft's descent by using emergency power on the working engines, allowing him to plan an emergency landing on Hainan. For the next 26 minutes, the crew of the EP-3 performed an emergency plan which included destroying sensitive items aboard the aircraft, such as electronic equipment related to intelligence-gathering, documents and data. Part of this plan involved pouring freshly brewed coffee into disk drives and motherboards and using an axe from the plane's survival kit to destroy hard drives. The crew had not been formally trained