Senior Australian pilots have described in detail how a US pilot pulled off an emergency landing in the Hudson River this morning, believed to be the first successful "ditching" of a commercial passenger plane.

Former fighter pilot Chesley Burnett "Sully" Sullenberger III, 57, safely guided Flight 1549 into the freezing waters of New York's Hudson River after a flock of birds reportedly cut the jet's engines.

Pilots have already posted hundreds of messages on online forums hailing Mr Sullenberger and his crew as heroes, and describing his effort as one of the greatest shows of "airmanship" ever.

Australian & International Pilots' Association president Barry Jackson said Mr Sullenberger had just minutes to perform a delicate operation that, had it not been executed perfectly, could have resulted in the plane cartwheeling on impact with the water and potentially killing those on board.

'Amazing job'

"It's an amazing job. I've got to tip my lid to him," Mr Jackson said.

"The crews have done a wonderful job to get out of LaGuardia [Airport], and avoid Manhattan Island and put the plane down on the Hudson River, without hitting any boats.

"When you have got nowhere else to go ... you've only got one go at it and it looks like he did it remarkably well.

"But it's something I don't hope to do in my whole career."

The drama started when a flock of birds reportedly collided with the plane, which the crew and passengers would have noticed immediately, Mr Jackson said.

"You're taking off at full power and if you've struck a number of birds, you're going to get some sort of vibration that everyone would have heard throughout the aircraft."

Flames

Passengers also reported seeing flames shooting out of the engines.

As the engines started faltering, Mr Sullenberger's first reaction would have been to assess whether the plane had enough thrust to keep flying to its destination, or even to return to the airport, Mr Jackson said.

But both engines appeared to have been critically damaged by the strike