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If your flight ticket says that your flight will be on a 737 MAX 9 in the next month or two, you need to contact your airline.

All Boeing 737 MAX 9 planes have been grounded for safety reasons after an unused cabin door came away from an Alaska Airlines airplane minutes after take-off on January 5, 2024.

������ϲʼ�ʱ����’s resident aviation journalist and airline expert, John Walton, breaks down what happened, what comes next, and what it might mean for your flight.

What happened to the Alaska Airlines Boeing 737 flight?

On a routine flight from Portland, Oregon to Ontario in southern California, a piece of the airplane known as a “door plug” blew out of an Alaska Airlines Boeing 737 MAX 9 whilst in the air. On board, it looks pretty scary since it seemed like an entire part of the wall just fell out.

What’s a door plug on an airplane?

Door plugs are essentially a kind of dummy door inserted into an optional emergency exit and fixed with special bolts to keep it in place. From the inside, it just looks like a regular bit of cabin wall.

The idea of an optional emergency exit might sound weird, but they exist to give airlines flexibility about how many seats to put on an airplane. The number of exit doors required depends on how many passengers might need to evacuate in an emergency.

If a plane has a lot of spacious business class and extra-legroom seats taking up more space in the cabin, it won’t have as many passengers, so won’t need as many exit doors. A low-cost carrier is tightly packed with all-economy seats and will require an additional exit door.

Could it happen again?

This is what safety regulators are concerned about. That is why all the affected planes have been grounded – they want to be sure that all the Boeing 737 MAX planes with these doors are safe.

One of the particularly unusual things about this incident is that door plugs have been used for decades, including on the 737 MAX 9’s older, similarly-sized predecessor.

According to, initial inspections by United and Alaska Airlines “found loose bolts and other parts” on some of the planes they had examined after Boeing flights were grounded.

While it’s concerning that Boeing has yet another production safety issue with its 737 MAX airplanes, it’s reassuring that the Federal Aviation Administration (FAA), the airline safety regulator in the United States, which has responsibility both for US airlines and for US-manufactured planes, seems to be taking a firm line on the investigation.

What planes are affected?

Most 737 MAX 9 models that are fitted with this kind of door plug. Some with more densely packed seats don’t have the door plug but an actual emergency door in its place. There is no suggestion that actual emergency exit doors have any issues.

MAX 8 and MAX 8-200 airplanes continue to fly as they either don’t have this kind of door or they’re being used as an actual emergency exit rather than as a door plug.

What airlines use these planes?

According to, 11 airlines have the 737 MAX 9, but only five use the door plugs – Aeromexico, Alaska Airlines, Copa (for some of its planes) and United.

When will these planes start flying again?

The short answer is when regulators are confident that the planes are safe and any production safety issues have been fixed by airline mechanics. The long answer is that the FAA will investigate. Given what we know so far, this will likely involve the process known as an Airworthiness Directive, where the FAA sends instructions to airlines after working with experts at Boeing and elsewhere to figure out the problem and how to fix it.

What about my flight?

A few hundred flights using the affected 737 MAX 9 planes have been canceled. Airlines won’t fly them again until the FAA has cleared them. As : “The safety of the flying public, not speed, will determine the timeline for returning the Boeing 737 Max 9 to service.”

Check your flight confirmation email or ticket and if it references that you are flying on a 737 MAX 9, contact your airline to see what your options are.