Alaska Airlines has grounded its fleet of Boeing 737 Max 9s hours after one such aircraft suffered a window blow-out after take-off.

Airline chief Ben Minicucci says the airline is taking “the precautionary step” to ground the Max 9s for “full maintenance and safety inspections”.

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Source: Creative Commons

Alaska Airlines has 65 737 Max 9s in operation.

Minicucci adds that the inspections are expected to complete “in the next few days”. Alaska Airlines has an in-service fleet of 65 Max 9s, as well as a sole Max 8.

“I am personally committed to doing everything we can to conduct this review in a timely and transparent way,” he adds.

The incident on 5 January involved a three-month-old Max 9 aircraft (N704AL), that was operating flight 1282 from Portland, Oregon to Ontario, California. It was carrying 171 passengers and six crew members.

About 20min after take-off, the aircraft made an emergency landing back at Portland.

Social media images shows a chunk of the aircraft’s left side wall missing, with oxygen masks deployed. Local media footage suggest it was the aircraft’s deactivated mid-aft door that blew out.

There were no reports of serious injuries or fatalities from the incident.

US aviation regulators have opened investigations, while Boeing says it is “working to gather more information” from Alaska.

The incident comes about a week after Boeing urged airlines to inspect 737 Max jets for a potentially loose bolt in the type’s rudder control system. The FAA, which is closely monitoring the inspections, said it would consider taking further actions “based on any discovery of loose or missing hardware”.