Alaska Airlines grounded its fleet of Boeing 737 Max 9 aircraft on Friday after a flight operated by the airline made an emergency landing at Portland International Airport in Oregon that evening because of a midair pressure problem that passengers said blew out a chunk of the fuselage.

The airline said that Alaska Airlines Flight 1282 had made a safe emergency landing carrying 171 passengers and six crew members at the Portland airport shortly after takeoff for Ontario, Calif. Within hours, the company said that it was grounding all 65 of its Boeing 737 Max 9 aircraft until it could inspect each plane. Those planes make up about a fifth of its fleet. It said in a statement that it expected to complete the inspections within a few days.