Both Alaska and United Airlines found problems with door seals on Boeing 737 MAX 9 planes after the “explosive” explosion late last week of the same piece of fuselage on a flight in Alaska. On Monday, Alaska reported that investigators found “loose hardware,” and United also reported loose screws.
Hardware failure can contribute to door plug displacement, although there are 12 “stop points” in the door plug design, according to the National Transportation Safety Board.
The agency is in the preliminary stages of its investigation into the incident that occurred Friday night on Alaska Airlines Flight 1282, which was traveling from Portland International Airport to Ontario. The NTSB found that the door had been moved upwards, and “all 12 stops had been disconnected, allowing it to exit the fuselage,” NTSB investigator Clint Cruickshanks said at a news conference Monday night.
Both United and Alaska grounded their commercial aircraft fleets and canceled hundreds of flights in the wake of the incident.
The plane reached an altitude of about 16,000 feet when the cabin underwent “significant decompression,” according to Jennifer Homendy, head of the National Transportation Safety Board, and a door seal blew off the side of the plane.
Among the revelations at a news conference Sunday night, the head of the NTSB said the door stopper the agency was searching for had been found by a teacher in Portland, Oregon, in his backyard.
The teacher, referred to only by his first name, contacted the NTSB via email and sent two photos of the fuselage piece, which was described as a 63-pound piece of the plane, yellow and green on one side and white. On the other hand. Two mobile phones that fell from the plane were also found in the vicinity.
“Bob was a star with all his students today,” Homendy said at Monday’s news conference.
The focus of the investigation Monday was a warning light on Flight 1282 that illuminated at least three times in the past month — including in the two days before the explosion on Friday night — possibly indicating a pressurization problem on the plane.
Homendy said Alaska Airlines grounded the plane from intercontinental travel so it could return to the airport during the emergency.
Due to the pressure light going off several times, additional maintenance on the aircraft has been requested, but has not yet been performed before Friday’s flight.
However, Homendy said Monday night that the light was part of a larger system that maintains safe cabin pressure, and that it was “working as designed.” She said there were “no indications at all that this is in any way related” to the plug door explosion.
This is not the first time that loose bolts have been discovered on Boeing 737 MAX 9 aircraft; In late December, Boeing issued a warning to all airlines with 737 MAX aircraft to inspect the plane for possible loose bolts in the rudder control system after one airline reported a nut missing during routine maintenance.
Boeing President and CEO David Calhoun sent a companywide email Sunday canceling the organization’s annual leadership retreat to host a “safety webcast” with members of the executive leadership team instead.
“Although we have made progress in strengthening our safety management and quality control systems and processes in the past few years, situations like this are a reminder that we must remain focused on continuing to improve every day,” the email said.
Federal officials on Sunday night also pointed to a major hurdle to the Alaska Airlines investigation: The cockpit voice recorder, or black box, had been erased from Friday night’s flight.
After the plane returned to Portland International Airport, no one pulled the circuit breaker on the cockpit voice recorder or retained the audio, which only retained the last two hours, Homendy said.
“The cockpit voice recorder was completely overwritten. There was nothing on the cockpit voice recorder,” Homendy said.
Homendy was visibly angry about the loss of the black box recording. She 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 get (the cockpit voice recorder), but it was about two hours away,” she said, adding later: “We don’t have anything.”
She pointed to about 10 other recent incidents when voice recorders were overwritten, including a 2017 near-disaster at San Francisco Airport when an Air Canada plane nearly landed on a taxiway and collided with other planes carrying about 1,000 passengers. The FAA and Congress called for a rule requiring new and existing aircraft to store sound for 25 hours, which is consistent with European sound retention practices.
“If that communication is not recorded, it is unfortunately a loss for us, a loss for the FAA, and a loss for safety, because this information is essential,” she said.
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 why the plane’s door plug exploded, Homendy demurred.
“We are now in the fact-finding phase of the investigation,” the head of the National Transportation Safety Board said, adding that employees were examining the Boeing 737 MAX 9 for evidence and planned to send key components to a lab to analyze any breakages and paint. Marks and cuts that can help explain what happened.
Upon examination of 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 exploded from the aircraft was covering an unused emergency exit hatch near rows 25 and 26, and was primarily attached to the airframe. The plug was covered with panels and included a window so that from inside the cabin it appeared indistinguishable from other rows.
On Sunday, Homendy praised the flight attendants and pilots for their quick response in what was a terrifying environment marred by communication problems.
It said passengers and crew reported hearing a “thud” when an “explosive decompression” occurred after the plug was expelled from the fuselage.
“It was described as chaotic and very loud,” she said. The cockpit door opened, the captain partially lost and the first officer completely missing his headphones.
“Flight attendants reported that it was difficult to obtain information from the cockpit, and the cabin crew had difficulty communicating,” Homendy said.
The plane was carrying a crew of six and 171 passengers, including three children and four unaccompanied minors.
“The hosts were very focused on what was going on with these kids. Were they safe? Were they safe?”
Fortunately, there were two empty seats next to where I opened the hole in the plane.
Seats in that area showed signs of damage, including torn oxygen masks, missing head restraints and torque.
“There has been significant damage to the interior panels and trim,” she said. “It must have been a terrifying event to experience.”
Although US airlines have grounded their aircraft, European airlines such as Air Iceland continue to use Boeing 737 MAX 9 aircraft; The planes do not have the same configuration covered by the FAA order, according to the European Union aviation safety agency.
Both the Boeing 737 MAX 9 and MAX 8 were previously grounded from March 2019 until November 2020 after two Boeing 737 MAX planes crashed in 2018 and 2019, killing all 346 people on board.
Max’s design included a larger motor, the placement of which would cause the vehicle to move. Software was created to counter this, but investigators determined that a faulty sensor led to the software system crashing under certain conditions.