United Airlines investigators found loose bolts and other door plug installation problems when investigating its fleet of Boeing 737 Max 9s — potential clues to how the same fuselage piece exploded on a recent Alaska Airlines flight.
Both United and Alaska grounded their commercial aircraft fleets and canceled hundreds of flights after the incident, which occurred on Alaska Airlines Flight 1282 from Portland International Airport to Ontario on Friday night.
The plane had reached about 16,000 feet when the cabin suffered “explosive decompression,” according to Jennifer Homendy, chairwoman of the National Transportation Safety Board, and the door plug came loose from the side of the plane.
Among revelations at a Sunday night news conference, the NTSB chief said the door plug the agency had been searching for had been found by a Portland, Oregon, teacher in his backyard.
“Thank you, Bob,” Homendy said.
The teacher, referred to only by his name, contacted the NTSB by email and sent two photographs of the fuselage piece, which was described as a 63-pound piece of aircraft that is greenish-yellow in color. side and white. in the other one. Two mobile phones that fell from the plane were also found nearby.
Additionally, Homendy said that before Friday’s midair incident, the plane had been restricted from long flights over water due to a warning light that had come on at least three times in the last month, possibly indicating a problem. of pressurization in the airplane.
“We don’t know if there was any correlation” between the warning lights and what happened during Friday night’s flight, Homendy said. But Alaska Airlines had restricted that plane to transcontinental routes so the plane could return to an airport during an emergency, she said.
Because the pressurization light had gone out several times, additional maintenance was ordered on the plane but had not yet been performed before Friday’s flight.
Federal officials also pointed out a major obstacle to the investigation Sunday night: The cockpit voice recorder, or black box, from Friday night’s flight was erased.
Homendy said that after the plane returned to Portland International Airport, no one turned off the circuit breaker on the cockpit voice recorder or otherwise preserved the audio, which only contains the most recent two hours.
“The cockpit voice recorder was completely overwritten. There was nothing on the cockpit voice recorder,” Homendy said.
Homendy was visibly exasperated by the loss of the black box recording. He noted that it was a “very chaotic event” when the plane landed and officials set up an emergency operations center.
“The maintenance team went out to look for [the cockpit voice recorder]but it was around two hours,” he said, and then added: “We don’t have anything.”
He pointed to 10 other recent incidents in which voice recorders were overwritten, including a near-catastrophe in 2017 at the San Francisco airport when an Air Canada plane nearly landed on a taxiway and reportedly collided with other planes carrying about 1,000. passengers. He called on the Federal Aviation Administration and Congress to implement a rule that would require new and existing aircraft to store audio for 25 hours, which aligns with European audio retention practices.
“If that communication is not recorded, unfortunately it is a loss for us and a loss for the FAA and a loss for safety,” he said, “because that information is key.”
Alaska Airlines did not respond to questions about the cockpit voice recorder or whether the airline would voluntarily install recorders that store audio for 25 hours.
When asked to offer any theories about what caused the plane’s door plug to burst, Homendy demurred.
“Right now we are in a fact-finding phase,” the NTSB chief said, adding that staff were thoroughly examining the Boeing 737-9 Max aircraft for clues and planned to send key components to a lab for analysis. any fracture. paint marks and cuts that could help explain what happened.
Upon inspecting the plane, officials found damage to more than a dozen rows inside, but did not identify any structural damage to the plane. The “plug” that flew out of the plane covered an unused emergency exit opening near rows 25 and 26, and was essentially bolted to the airframe. The socket was covered with panels and included a window so that, from inside the cabin, it appeared indistinguishable from other rows.
On Monday, investigators had planned to examine the door stopper on the other side of rows 25 and 26 to try to determine what caused the other stopper to come loose.
Homendy praised the flight attendants and pilots for their quick response in a frightening environment plagued by communication problems.
Passengers and crew reported hearing “a pop,” he said, when “explosive decompression” occurred after the plug was ejected from the fuselage.
“It was described as chaos, very loud,” he said. The cockpit door was flung open and the captain partially lost and the first officer completely lost their respective headsets.
“Flight attendants reported that it was difficult to get information from the flight deck and that the flight deck also had difficulty communicating,” Homendy said.
The plane had six crew members and 171 passengers, including three babies and four unaccompanied minors.
“The flight attendants were very focused on what was happening with those children. Were they safe? Were they sure?
Luckily, two seats were empty right next to the hole in the plane.
The seats in that area showed signs of damage, including broken oxygen masks, missing headrests and twisting.
“There was a lot of damage to the interior panels and trim,” he said. “It must have been a terrifying event to experience.”
