A source close to the investigation told the agency that 'sounds uncharacteristic of routine flight were recorded' on board just before the plane crashed.

It began as a routine flight across one of the world's most beautiful wildernesses, but it ended in shock.

Conventional jet engines use many thousands of litres of expensive kerosene on a routine flight and are very noisy.

For the next 4 hours and 25 minutes the routine flight proceeded as planned.

Their seemingly routine flight takes a strange turn, when they are affected by a blinding light and accompanying loud sound.