THE pilot of a transport plane which plunged into the sea off Kai Tak airport, killing three people and leaving another three missing, claimed yesterday that the crash was caused by engine failure. As experts from Britain and Indonesia arrived in the territory to investigate the accident, the captain of the ill-fated Lockheed L100-30 Hercules, Soeyono Sanardhi, said a turboprop engine on the extreme right of the aircraft cut out with a 'loud bang' seconds after takeoff. The four-engined transporter then veered violently to the right, away from the runway, and plunged into the murky waters of Victoria Harbour just outside Kowloon Bay Typhoon Shelter. Speaking to the Sunday Morning Post from his bed in Queen Elizabeth Hospital, Captain Sanardhi, 40, said he only had a few seconds to brace himself before the crash. 'It was 'bang, bang' and I looked out. Then we went down,' he said. A pilot for 17 years, with 13 spent flying Hercules aircraft, Captain Sanardhi said the cockpit and the tip of the right wing hit the water before the plane went under and then bobbed back to the surface for a short time, giving the six survivors their chance to escape. It then sank to the bottom, coming to rest on its tail after rolling on its side. The chartered Indonesian-owned plane, with 12 crew on board, was leaving for Jakarta at 7.14 pm after returning to Kai Tak to drop off Hong Kong security staff, who had escorted 33 Vietnamese boat people to Hanoi as part of the orderly repatriation programme. As divers spent the day examining the wreckage on the seabed, Kwan Hok-chun, the Civil Aviation Department's (CAD's) chief safety officer, was put in charge of the operation to discover the cause of the crash. Pelita Air Service of Jakarta, which owns the plane, and the UK-based HeavyLift Cargo Airlines, which hired the Hercules, are also investigating the accident. An experienced Royal Air Force (RAF) officer with more than 7,000 hours flying in Hercules said if an engine failed suddenly it could cause a massive amount of drag on one side of the aircraft which could make it veer off course. Squadron Leader Roy Harper, who commands the RAF unit at Kai Tak, said there had been at least one incident with a Hercules 20 years ago in which this happened on takeoff, resulting in the plane crashing. 'My judgment is that if the plane suffered an inexplicable, catastrophic failure, that would cause the drag,' he said. The wreckage of the aircraft is in six metres of water just outside the typhoon shelter wall, and about 40 metres northwest of a marker buoy. According to Royal Navy diver Chief Petty Officer Darby Allan, the rear of the plane is embedded in mud, which could make it difficult to salvage. CAD director Peter Lok said yesterday that an initial report on the cause of the accident should be ready before the end of the year if data from the black box flight information recorder could be found. Divers failed to locate it yesterday. The Government has appointed Hong Kong Towage and Salvage company to carry out an underwater survey of the aircraft with a view to assessing the best method of bringing it to the surface. Evidence from the survivors and the remains of the fourth engine, which should be recovered from the seabed shortly, will be crucial in the investigation that has been launched to find out why the Hercules crashed. Meanwhile, four survivors of the crash were released from Queen Elizabeth Hospital last night. Mechanical engineer Amas Susanto, 52, flight officer Haryanto, 53, cabin attendant Aries Maral, 43, and Captain Sanardhi have been invited to stay at the Indonesian Consulate until they are able to speak to crash investigators. Of those still in hospital, cabin attendant Joseph Hermanus Tapilatu, 40, remains in critical condition, while flight officer Haris Permana, 33, is in fair condition. Those confirmed dead yesterday were flight officer and co-pilot Bambang Sukomartono Soekotjo, 34, cabin attendant Zarmis Kinan, 50, and Captain Ignatius Soenoto, 50. The missing crew are Captain Adisuryawardana, flight engineer Bambang Haryono Kartowardoyo and mechanical engineer Eldon Karta Siahaan. Police officers interviewed survivors twice yesterday. Detective Inspector Mike Johnson said there were no suspicious circumstances. Secretary for Security Alistair Asprey said the accident would not stop repatriation flights. However, the Government only signs single-trip contracts for these flights and no further contracts have yet been signed with HeavyLift, according to a company spokesman in Hong Kong.