The air force has grounded all of its F-5F jet fighters after a twin-seat plane of this type crashed into the sea off the outlying island of Penghu Wednesday during a routine training flight, according to a military spokesman. The ill-fated plane took off from Chingchuankang air base in central Taiwan at 11: 14 a.m. for an air-to-ground attack drill over a rocky reef area, but it disappeared from military air traffic control radar at 11: 36 a.m. Shortly afterwards, an air force S-70C rescue plane flew to Penghu to conduct a search and rescue mission. As of 3 p.m., reports said that wreckage from the fighter, as well as two bodies -- believed to those of the pilot and flight instructor -- had been located in waters off Penghu. But Hsieh Mao-sung, the political warfare chief of Air Force 427 Wing, said at a news conference that further verification was required to determine whether the bodies were indeed those of the officers. The plane was being flown by pilot Huang Ting-yu, a 26-year-old lieutenant, when it lost contact with air traffic controllers. The flight instructor, 43-year-old Lt. Col. Chang Liang-yuan, was sitting in the back seat. According to Hsieh, Huang was a bachelor who had a flight record of 294 hours, while Chang was the father of two young sons. Taiwan has around 60 F-5s, development of which began in the 1950s. Hsieh said the planes are now mainly used as trainers in preparation for pilots being groomed to fly new-generation jet fighters. 'All F-5F-related training projects have been suspended following the latest flight incident, ' Hsieh said, adding that training flights will not resume until after the cause of the crash is ascertained. He said the air force has formed a special task force that will conduct an investigation. According to Hsieh, the plane had undergone regular maintenance in accordance with air force regulations before being flown on the routine training flight. Moreover, he added, the plane was unarmed. As to why the plane was being flown by the junior pilot, Hsieh pointed out that it is a long-observed tradition in air force routine training that the junior officer sits in the front seat and flies the plane, with the senior officer sitting in the back seat providing instructions. 