23 Jan 1980 reportedly 'some 2.5hr after departure from Sharjah while the aircraft was over Turkey, the No. 3 engine began to vibrate severely and almost immediately afterwards failed. A few minutes later the No. 4 engine began to vibrate and the pilot elected to shut it down. However, not long after this the No. 2 engine also began to vibrate. The pilot attempted to reduce the vibration by reducing power on the engine but this was not entirely successful. The pilot declared an emergency and diverted to Ankara where a safe landing was made about 1.5hr later. A subsequent inspection of the oil filters on the four engines found that all were heavily contaminated by sand and fragments of metal.'
Khan's father, Khan and his family were on board I think and it was said that some one had 'helped' the sand to get into the oil.