Boeing officials said they had identified the most likely ways in which the batteries could fail. They contend that the proposed changes would minimize the odds of future incidents and protect the plane and its passengers if a problem does arise. Meanwhile, the safety board plans to continue its investigation, and said Thursday that it would hold a hearing on the hazards of lithium-ion batteries next month.

The report said the airplane involved in the Boston incident was delivered to Japan Airlines on Dec. 20. At the time of the fire, it had logged 169 flight hours and 22 flight cycles.

The plane had flown from Narita, Japan, and touched down in Boston at 10 a.m.

The flight data recorder showed that at 10:04 a.m., the pilots started the auxiliary power unit, which provides power while the plane is on the ground and is energized by one of the plane’s two lithium batteries.

That battery is in the electronics bay, which is under the main cabin, near the middle of the plane. The other lithium-ion battery, located in the front of the plane, provides power to the cockpit. It was that battery that emitted smoke in the incident in Japan.

The possibility that there could be a fire in the advanced plane was so surprising that the airline’s station manager in Boston, Ayumu Skip Miyoshi, could not initially believe the radio call he got from a maintenance employee who reported smoke in the cabin.

“I wasn’t sure what he meant, therefore I replied, ‘So you mean one passenger smoked in the lavatory?’ ” he said in a witness statement. He rushed from his office and tried to enter the cabin but could not see more than 10 feet from the door because the smoke was so intense.

Meanwhile, one of the plane’s crucial safety mechanism intended to keep smoke out of the cabin in case of a problem did not work. The venting system had lost power after the auxiliary power unit shut down.