TOKYO - Pilots on a Japan Airlines plane engulfed in flames just after all 379 passengers and crew escaped were initially unaware the aircraft was on fire, according to fresh details reported on Thursday.

The airliner collided with a coast guard plane after landing at Tokyo's Haneda Airport on Tuesday evening. All but one of the six people on the smaller aircraft were killed.

A ball of flame erupted from the airliner before it came to a halt, with the fire beginning to spread from underneath the aircraft, footage shot by passengers showed.

But according to national broadcaster NHK, the Japan Airlines pilots in the cockpit did not know about the fire before being informed by the cabin crew.

Of the nine flight attendants on board, the chief reported to the cockpit that the plane was burning as the cabin crew needed permission to open the emergency exits, NHK reported.

By this time, the cabin was filling with smoke and getting hotter, with babies crying and people begging for the doors to be opened, footage showed.

There were eight emergency exits but the evacuation began from two slides at the front of the plane because of the fire.

Only one other exit at the rear left was safe from the fire, but the intercom system was no longer functioning, so the cockpit could not give the go-ahead, JAL said.

The crew in the back deemed it was urgent for the passengers to disembark from the back door and opened it anyway, as they are trained to do.

They used megaphones and their own voices to give instructions to the passengers.

It took 18 minutes to evacuate the entire plane, with the pilot the last person to set foot on the tarmac at 6:05 pm.

Soon afterwards, the entire aircraft was an inferno and dozens of fire engines tried to put out the blaze. That process ended up taking eight hours.

Investigators from Japan, France, Britain and Canada were probing the crash on Thursday, with charred remains of the two planes still littering one of Haneda's four runways.

The flight recorder and the voice recorder from the coast guard plane had been found, but those of the passenger jet were still being sought.

The transport ministry released on Wednesday transcripts of flight controllers' communications, which showed that they approved the JAL flight's landing, media reports said.

But the coast guard plane was reportedly instructed to go to a spot near the runway.

Earlier on Wednesday, NHK had reported that the pilot, Genki Miyamoto, 39, said immediately after the accident that he had permission to take off.

AFP