The Alaska Airlines plane that lost a piece of its fuselage in midair on Friday was not being used for long flights over water because the pressure warning light went off during three recent flights, the National Transportation Safety Board said Sunday.
Jennifer Homendy, the board’s president, said it was too early to say whether the problem played a role in Friday’s accident, which grounded 171 Boeing 737 Max 9 planes in the United States. “It’s definitely a concern, and we want to dig into it,” Homendy said at a news conference in Portland, Oregon.
Alaska Airlines maintenance workers were instructed to determine why the warning light repeatedly went off, but the work was not done before the flight Friday, she said. Instead, Ms. Homendy said, workers reset the system and the plane was returned to service, even though the airline banned its use on flights to destinations such as Hawaii.
She said the safety board was trying to get more information about what happened during the three flights when the light went out, all of which happened since Dec. 7.
Friday’s accident on Alaska Airlines Flight 1282, bound for Ontario, California, occurred at 16,000 feet and forced the pilots to return to Portland International Airport shortly after takeoff. None of the 171 passengers and six crew members on board the plane were seriously injured, but they were exposed to strong winds from the hole in the plane’s body while the pilots made the emergency landing.
Authorities focused their attention on the mid-cabin door seal, which is part of the fuselage piece that was torn from the plane. Ms. Homendy said Sunday that investigators recovered the door stopper from the backyard of a Portland home. Door seals are used to fill emergency exits that are not required because the aircraft is equipped with less than the maximum possible number of seats.
Ms Homendy also said there was no information about the plane’s cockpit voice recorder, because the device started re-recording after two hours, erasing previous data, and it was not retrieved in time. The Safety Board, which has been pushing for the two-hour period to be extended to 25 hours, has conducted 10 investigations since 2018 in which the cockpit voice recorder was similarly overwritten, Ms. Homendy said.
“Cockpit voice recorders are not only appropriate for use by the NTSB in investigations or the FAA for use in investigations,” she said. “They are essential to help us pinpoint exactly what is happening.”
Ms. Homendy said the force of decompression during Friday’s incident caused the cockpit door to open, causing one of the pilots to lose his headset. The headrests were separated from the seats, the seatbacks were gone and clothes were scattered all over the plane.
Sunday was the first full day of the investigation into the incident, which has drawn new attention to the Max plane and its troubled history. Max planes were grounded worldwide after two Max 8 planes crashed within several months in 2018 and 2019, killing hundreds.
On Saturday, the Federal Aviation Administration announced mandatory inspections of 171 Max 9 aircraft used by American airlines. Alaska Airlines, which has 65 planes, canceled 170 flights Sunday due to demand. United Airlines, which has 79 Max 9 planes, more than any other airline, said it canceled about 270 flights over the weekend.