The Federal Aviation Administration said Monday that airlines can begin inspections of more than 100 Boeing 737 Max 9 planes, which have been grounded amid an investigation into an explosive depressurization accident Friday that triggered an emergency landing and resulted in extensive damage to an Alaska Airlines plane.
There were no serious injuries in the accident, which is being investigated by the National Transportation Safety Board, but the dramatic midair incident caused the FAA to order immediate inspections of the jetliners. Guidance issued Monday by Boeing and approved by the FAA allows the inspections to begin. The FAA said the inspections could take four to eight hours per plane.
“The safety of our airplanes and everyone who steps onboard is a core Boeing value,” Stan Deal, commercial airplanes president and chief executive, and Mike Delaney, chief aerospace safety officer and senior vice president of global aerospace safety, wrote in a message to employees Monday. “We agree with and fully support the FAA’s decision to require immediate inspections of 737-9 MAX airplanes with the same configuration as the affected airplane.”
Deal and Delaney noted that the affected assembly is not found on other versions of 737 Max jets.
The executives said Boeing teams, with thorough FAA review, have provided comprehensive, technical instructions needed by airline operators, another step that would clear the way for the required inspections to begin.
“The FAA’s priority is always keeping Americans safe,” the agency said in a statement, adding that all Max 9 aircraft would remain grounded until operators have completed the enhanced inspections.
The FAA’s emergency airworthiness directive grounding the planes affects 171 aircraft. Two airlines in the United States—Alaska Airlines and United Airlines—have Boeing Max 9 aircraft in their fleets.
Inspections will be required on both the left and right cabin-door exit plugs, door components and fasteners. Operators must also complete corrective-action requirements based on findings from the inspections before bringing any aircraft back into service, the FAA said.
Dave Calhoun, Boeing’s chief executive, also announced that a companywide safety meeting is scheduled for Tuesday.
News that the inspections can begin came a day after the NTSB announced it had recovered a key portion of evidence from the accident—the door plug that blew out of the Alaska Airlines plane over Portland, Oregon.
Jennifer Homendy, the NTSB chair, announced that the piece had been found in a schoolteacher’s yard.
Jeff Guzzetti, a former accident investigator with the FAA and NTSB, said the door plug is a key piece of evidence that will allow investigators to confirm whatever failure occurred and how it occurred.
“I still believe that because it was such a new airplane and this is such a unique type of event that it’s manufacturer-related,” he said, though the investigation into the exact cause is ongoing.
At a briefing Sunday night, Homendy said Alaska Airlines recorded that the plane’s auto-pressurization fail light—designed to signal failures in the control of cabin pressure—had illuminated on three flights in the weeks before Friday’s incident. Those reports—on Dec. 7, Jan. 3 and Jan. 4—prompted tests and a reset by maintenance, she said.
Homendy said that the airline had restricted the plane from flying to Hawaii in case of the need for a swift landing, and that a later request from Alaska Airlines for a deeper look had gone unfulfilled before Friday’s incident.
“It’s certainly a concern, and it’s one that we want to dig into,” Homendy said. She added that it’s unclear whether the light is linked to the accident, saying it’s possible it could have malfunctioned independently of the plane’s auto-pressurization system.
Guzzetti said reports of irregularities with the plane’s auto-pressurization lights should be examined closely but may simply be indications of symptoms of wear to the door plug or potentially a loosening. He added that it is not unusual for auto-pressurization warning lights to go off. Sometimes the sensors themselves fail; other times, it can be an indication of a pressurization problem.
“In this case, it may be a small consequence of what may have been happening to that door’s lock,” he said.
Flight 1282 was on its way to Ontario, California, from Portland when it had to return to the airport shortly after takeoff because the door plug—an exit that is paneled off, usually because it is deemed optional in safety regulations—had separated from the plane in midair.
The blowout caused a loud banging sound and allowed frigid, whipping winds to pour into the aircraft.
The cockpit door immediately flew open, banging into a lavatory door and jolting the first officer forward, causing her to temporarily lose her headset, Homendy said, citing interviews with flight attendants. The captain and the first officer were able to put on oxygen masks and turn on a speaker, but “communication was a serious issue,” she said.
Flight attendants described trouble getting information from the flight deck, and passengers in the cabin struggled to hear announcements. “It was very violent,” Homendy said.
Investigators who examined the grounded plane after the accident found that the headrests of two seats directly adjacent to the door plug were missing, as well as the back of one seat.
One flight attendant suffered minor injuries, according to the union that represents Alaska crews, The Washington Post reported. Several passengers required medical attention for injuries, the airline said. The flight was carrying 171 passengers and six crew members.
Pieces of trim, paneling and insulation were ripped from the interior of the plane, Homendy said, and damage was visible in at least 12 rows, including the interior side of some windows. However, these parts are “not critical to the structure of the aircraft,” she said, adding that the tubing of several oxygen masks had been “sheared off.”
“My impression, when I saw that, was it must have been a terrifying event to experience,” she said.
NTSB investigators were unable to uncover communications from the cockpit voice recorder, which overwrites itself every two hours and was not recovered before the recording had been automatically erased. Homendy called on the FAA to implement a rule that would require the automatic overwrite time to be increased to 25 hours, a standard she said the NTSB has called for and is “consistent with Europe and many other countries.”
“That information is key not just for our investigation but for improving aviation safety,” she said.
The accident has fueled new scrutiny of Boeing after it closed out a turbulent year. Videos recorded by passengers, which show dropped oxygen masks and the blown-out door plug, with lighted buildings down below, rapidly racked up views on social media. Before the accident, the company was already aware of manufacturing problems with the 737 Max 9 and had struck a deal in October with a key supplier to address issues with the model’s fuselage, the main body of the aircraft.
The NTSB is expected to continue its investigation into the causes of the accident. Members of the Portland community had launched drones to help search for the plug, and two cellphones were turned in after they were discovered in a yard and on the side of a road. Homendy asked people living or working near the site of the emergency landing to check their rooftops for any fallen parts, and to search their security camera recordings around the time of 5:11 p.m. for any potential evidence that would help investigators.
“We’ve only been on scene for 24 hours—one day. We have a lot of work to do,” Homenday said Sunday. “… This could be, you know, weeks that we’re here.”