What to know about Boeing 737 Max groundings after Alaska Airlines emergency

The Federal Aviation Administration (FAA) grounded more than 100 Boeing planes Saturday, after an Alaska Airlines flight suffered an inflight blowout that left a large hole in the side of the aircraft and prompted it to make an emergency landing. Here’s what to know about the incident and the ongoing fallout: An Alaska Airlines flight from Portland, Ore., to Ontario, Calif., evening suffered an Fridaywhen a panel plugging an exit door on the Boeing 737 Max 9 aircraft blew off just minutes after takeoff.

Videos of the incident showed passengers wearing oxygen masks after the blowout, which left a gaping hole in the side of the fuselage. The plane made an emergency landing back at Portland International Airport, and no injuries were reported. After the incident, Alaska Airlines CEO Ben Minicucci said the airline would perform full safety inspections on its remaining Boeing 737 Max 9 planes and was working with Boeing and federal regulators to determine what happened.

“My heart goes out to those who were on this flight — I am so sorry for what you experienced. I am so grateful for the response of our pilots and flight attendants,” he said in a statement. “We have teams on the ground in Portland assisting passengers and are working to support guests who are traveling in the days ahead,” Minicucci added at the time.

The FAA ordered the of about 171 Boeing 737 Max 9 aircraft operated by U.S. airlines or in U.S. territory on Saturday. “The FAA is requiring immediate inspections of certain Boeing 737 MAX 9 planes before they can return to flight,” FAA Administrator Mike Whitaker said in a statement. “Safety will continue to drive our decision making as we assist the [National Transportation Safety Board’s] investigation into Alaska Airlines Flight 1282,” he continued.

Alaska Airlines 18 of the planes to service on Saturday, before receiving notice from the FAA on Sunday that the aircraft may need additional work. The grounding has resulted in hundreds of flight cancellations for Alaska Airlines and United Airlines, the only U.S. airlines that fly the Boeing 737 Max 9 aircraft.

Jennifer Homendy, chair of the National Transportation Safety Board (NTSB), said Sunday that a that could have indicated a pressurization problem with the planes lit up on three earlier flights, twice last week and once in early December. The warning light prompted Alaska Airlines to restrict the jet from completing long flights over water so it “could return very quickly to an airport” if the light turned on, Homendy said at a press conference.

However, the NTSB chair also warned that the warning lights may be unrelated to the door plug that come off on Friday’s flight. Shares of Boeing and aerospace supplier Spirit AeroSystems tumbled when the markets opened Monday morning. Spirit AeroSystems reportedly manufactured and initially installed the fuselage part that suffered a blowout on Friday, according to .

Boeing stock fell nearly 9 percent after the opening bell, while Spirit AeroSystems plunged about 14 percent. Both had recovered slightly by midday..