World Bulletin / News Desk

Recordings show apparent confusion between the pilot and air traffic control over the runway approach at Kathmandu airport as Nepal Tuesday began investigating its deadliest plane crash in decades.

Witnesses have described how the US-Bangla Airways plane carrying 71 people abruptly changed direction moments before it crashed.

On Monday the airline's chief executive Imran Asif said there had been a "fumble from the control tower" as the plane approached the airport's single runway.

But airport manager Raj Kumar Chhetri told AFP it was too early to say what had caused the mountainous country's deadliest crash since 1992.

"It is yet to be identified whether the pilot or air traffic control was wrong," he said, adding the investigation would be carried out with Bangladesh.

Recordings of the conversation between air traffic control and the pilot appear to indicate confusion over which end of Kathmandu airport's single runway the plane was to approach.

Air traffic control can initially be heard clearing the plane to land from the southern approach.

"You are going towards runway 20," the controller is heard saying seconds later, referring to the northern end of the tarmac. 

A series of confused messages follow just before the crash in which the pilot says they will land at "runway 20" and then "runway 02" -- the southern end.

"There is certainly considerable confusion from air traffic as to which runway the aircraft actually wants to land on," said Britain-based aviation expert Andrew Blackie, who has reviewed the recordings.