Alaska Airlines Flight 1282 experienced a major depressurisation incident soon after taking off at about 5.06pm Pacific Time on Friday, but was able to land back at Portland International Airport about 20 minutes later with all its 171 passengers and six crew members safe and accounted for.
Posts uploaded to social media show a window and a portion of the side of the plane missing and oxygen masks deployed.
Dramatic accounts from eyewitnesses described a child sat nearest to the window breach who had to be held down in their seat as loose items like mobile phones flew out of the plane due to the sudden loss of pressure.
Some accounts indicated that the seat nearest to the blown-out window – which was unoccupied at the time – was ripped out, though this could not be immediately confirmed.
Photos shared on the image-sharing website Imgur also show that the rear mid-cabin exit door separated from the aircraft during the flight.
Data from the tracking site indicated the aircraft reached its planned maximum altitude of 16,325ft during the flight.
Alaska Airlines plane loses window mid-air
The US Federal Aviation Administration said the crew reported a pressurisation issue, and that it would further investigate the incident.
“Whenever you have a rapid decompression such as this, it’s a major safety event,” Anthony Brickhouse, an air safety expert at Embry-Riddle Aeronautical University, told Reuters.
“This is a very, very serious situation and it could have been a lot worse,” he added.
Boeing said in a statement that it was looking into the incident, adding that a technical team stood ready to support the investigation.
“We are aware of an incident involving Alaska Airlines Flight AS1282… We are investigating what happened and will share more as it becomes available,” the airline posted on X.
“Following tonight’s event on Flight 1282, we have decided to take the precautionary step of temporarily grounding our fleet of 65 Boeing 737-9 aircraft,” the company said in a statement.
The airline said each of the temporarily grounded aircraft would only be returned to service after completion of full maintenance and safety inspections in the next few days.
“My heart goes out to those who were on this flight – I am so sorry for what you experienced,” Alaska Airlines chief Ben Minicucci said in a statement.
“We are working with Boeing and regulators to understand what occurred tonight, and will share updates as more information is available. The National Transportation Safety Board is investigating this event and we will fully support their investigation,” Mr Minicucci added.
The Boeing 737 Max has come under scrutiny by the FAA in the past.
The passenger airliner was grounded for 20 months worldwide after two fatal crashes in 2018 and 2019 that killed 346 people in Ethiopia and Indonesia.
Boeing is currently awaiting certification of its smaller 737 Max 7 and larger Max 10, according to Reuters.
In 2021, the FAA said it was tracking all 737 Max airplanes using satellite data.