Boeing 737 Max 9: What to know if you’re about to fly one

Alaska Airlines resumed a limited number of flights with its Max 9s on Friday. United aims to follow suit on Sunday, but a spokeswoman said the airline might use them as spare planes Friday or Saturday.

Those are the only two U.S. airlines that operate this particular model of the Boeing 737.

After seeing video of the frightening flight of a plane with a gaping hole in its side, passengers might reasonably be asking questions about safety.

The Federal Aviation Administration has detailed the process that airlines must follow to inspect — and if necessary, repair — the panels called door plugs, one of which broke loose on Alaska Airlines flight 1282 on Jan. 5. The plugs are used to seal holes left for extra doors on the Max 9 when an unusually high number of seats requires more exits for safety reasons.

FAA Administrator Mike Whitaker says his agency’s review of everything that has happened since the accident, including gathering information about inspections of door plugs on 40 other planes, gives him confidence that they will be safe so long as the new inspection process is followed.

WHY WERE THE PLANES GROUNDED?

Alaska Airlines grounded all 65 of its Max 9 jets within hours after one of the two door plugs in the back half of the cabin of flight 1282 blew away while 16,000 feet above Oregon. The FAA grounded all Max 9s in the U.S. the day after the blowout.

Even though none of the passengers were seriously injured, regulators acted quickly because the accident could have been far worse.

By a stroke of luck, the two seats closest to the panel that blew off the plane were empty when flight 1282 took off from Portland, Oregon. And the plane had not yet reached cruising altitude of more than 30,000 feet, when passengers and flight attendants might have been…