Investigators were focusing on communication between air traffic control and two aircraft at Tokyo's Haneda Airport on Wednesday, a day after a large passenger plane and a Japanese coast guard aircraft collided on the runway and burst into flames, killing five people.

The accident occurred Tuesday evening when the Japan Airlines flight 516 plane landed on one of Haneda's four runways after the coast guard aircraft — a Bombardier Dash-8 — had also entered, preparing to take off.

An orange fireball erupted from both aircraft as the JAL plane continued down the runway covered in flames while spewing gray smoke. Within 20 minutes, all 379 passengers and crew members slid down emergency chutes and survived. The pilot of the coast guard plane, which exploded, evacuated with injuries but five crew members were killed.

The Transport Ministry released a transcript of air traffic control communication of about 4 minutes and 27 seconds just before the crash. It showed no clear takeoff approval for the coast guard plane. According to the text, the Tokyo air control gave the JAL Airbus A350 permission to land on Runway C, noting that there is a departing plane, with the JAL pilot repeating the action.

The coast guard plane said it was taxiing to the same runway, and the traffic control instructs it to proceed to the stop line ahead of the runway. The controller noted the coast guard gets the departure priority, and the pilot said he was moving to the stop line.

Their communication ends there. Two minutes later, there was a three-second pause, apparently indicating the time of the collision.

Police began a separate probe into possible professional negligence. Tokyo police said that investigators examined the debris on the runway and were conducting interviews.

The JAL plane had flown from Shin Chitose airport near the northern city of Sapporo, and the coast guard Bombardier was preparing to depart for Niigata to deliver relief supplies to the central regions hit by powerful earthquakes on Monday that killed more than 60 people.

On Wednesday, six experts from the Japan Transport Safety Board examined what remained of the aircraft, the board said. TV footage showed the severely damaged A350's wings among the charred, broken parts of fuselage. The smaller coast guard plane resembled a mound of rubble.

Investigators plan to interview the pilots, officials as well as air traffic control officials to find out how the two planes simultaneously ended up on the runway, JTSB said.

The two sides had different understandings of their permission to use the runway.

JAL Managing Executive Officer Tadayuki Tsutsumi told a news conference late Tuesday that the A350 was making a "normal entry and landing" on the runway. Another JAL executive, Noriyuki Aoki, said the flight had received permission to land.

Air traffic officials gave the JAL airliner permission to land while telling the coast guard pilot to wait before entering the runway, the Transport Ministry transcript showed. But according to an NHK television report, the coast guard pilot said he was given permission to take off. The coast guard said officials were verifying that claim.

All passengers and crew members left their baggage and slid down the escape chutes within 20 minutes of the landing as smoke filled the cabin of the burning aircraft — an outcome praised by aviation experts. Videos posted by passengers showed people covering their mouths with handkerchiefs as they ducked down and moved toward the exits. Some passengers told news media they felt safe only after reaching a grassy area beyond the tarmac.

"The entire cabin was filled with smoke within a few minutes. We threw ourselves down on the floor. Then the emergency doors were opened and we threw ourselves at them," Swedish passenger Anton Deibe, 17, told Swedish newspaper Aftonbladet. "The smoke in the cabin stung like hell."

The fire is likely to be seen as a key test case for airplane fuselages made from carbon-composite fibers — featured on the A350 and the Boeing 787 — instead of conventional aluminum skins.

"This is the most catastrophic composite-airplane fire that I can think of. On the other hand, that fuselage protected (passengers) from a really horrific fire — it did not burn through for some period of time and let everybody get out," safety consultant John Cox said.

Haneda's three other runways reopened late Tuesday, but about 140 flights had been canceled Wednesday alone due to the closure of the runway, transport officials said. The airport was packed Wednesday as many holidaymakers wrapped up their New Year travel, including those who who survived the fire and spent the night at the airport or at nearby hotels, trying to change their flights.

Haneda is the busier of the two major airports serving the Japanese capital, with many international flights, and is favored by business travelers due to its proximity to central parts of the city.

Tuesday's accident was the first severe damage to an Airbus A350, among the industry's newest large passenger planes. It entered commercial service in 2015. Airbus said in a statement it was sending specialists to help Japanese and French officials investigating the accident, and that the plane was delivered to Japan Airlines in late 2021.

JAL operates 16 of the A350-900 version aircraft, according to its website. The twin-engine, twin-aisle A350 is used by a number of long-haul international carriers. More than 570 of the aircraft are in operation, according to Airbus.