Four minutes after takeoff (at 5200 feet), during a high-speed climbout, the flight crew reported no. 2 engine problems. Taipei ATC then gave the flight radar vectors to turn left for a return to the airport. One minute and 45 seconds later the crew reported unable to turn left, so ATC gave permission to turn right. This was the last contact with the flight. Control was lost and the aircraft crashed into a hillside, right wing-first, at an altitude of 700 feet. It appeared that the no. 3 engine had separated from the wing. The engine struck the no. 4 engine, which separated also. The aircraft had accumulated 45868 hours, of which 74 hours since the last A-check maintenance on December 21, and 9094 cycles. Load factor of this flight was 90%. PROBABLE CAUSE: Initial findings suggest a failure of both no.3 engine inboard midspar fittings, partly in fatigue partly ductile.