The Federal Aviation Administration on Saturday ordered the immediate grounding of Boeing 737 Max 9 jetliners, the same kind of aircraft that suffered a mid-air panel blowout during an Alaska Airlines flight out of Portland, Ore. on Friday.

A total of 171 planes worldwide are required to undergo emergency inspections, which typically last around four to eight hours per aircraft, before they’re allowed to return to the sky, officials said in a statement. That includes all 65 of the Boeing 737 Max 9s in Alaska Airlines’ fleet.

“Each aircraft will be returned to service only after completion of full maintenance and safety inspections,” Alaska Airlines CEO Ben Minicucci said in a statement, adding the inspections will likely take a few days to complete.

As of Saturday morning, about a quarter of the jetliners had already been inspected “with no concerning findings” to report.

“We deeply apologize to our guests whose flights have been impacted,” the airline added. “Guests whose travel has been impacted can go online to view flight options and rebook travel, place the value of their ticket in their Mileage Plan Wallet for future use, or request a refund.”

Alaska Airlines Flight 1282, at the time bound for Ontario, Calif., had climbed some 16,000 feet on Friday, when the jetliner blew out a window and what appeared to be a portion of its fuselage. A child sitting in the same row had his shirt sucked off his body and out the plane, while others lost personal objects, like cellphones, in the sudden chaos.

Images and video shared on social media see both passengers and crewmembers donning oxygen masks in front of a gaping hole left in the side of the plane.

“We need to turn back to Portland,” the pilot told controllers in a calm voice.

The Boeing plane, carrying 171 passengers and six crew members, safely touched back down at Portland International Airport about 20 minutes after it had departed, and some 13 minutes after the blow out.

With News Wire Services