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 night due to an air pressure issue that officials said passengers, a piece of the fuselage exploded.

The airline said Alaska Airlines Flight 1282 had made a safe emergency landing with 171 passengers and six crew members at the Portland airport shortly after taking off for Ontario, California. Within a few hours, the company saying that it would ground all 65 Boeing 737 Max 9 planes until it could inspect each plane. Those planes make up about a fifth of its fleet. he said he in a statement which expected to complete the inspections within a few days.

Boeing’s Max planes have a troubled history. After two Max 8 plane crashes killed hundreds of people within several months in 2018 and 2019, the Max was grounded around the world.

Passengers on Friday’s flight described a disconcerting experience during the approximately 15 minutes the plane returned to the airport. As the yellow oxygen masks hung above their heads, a powerful wind blew through a huge hole that showed the night sky and the city lights below.

The crew reported a “pressurization issue” before the emergency landing, the Federal Aviation Administration said in a statement. Alaska Airlines Flight Attendants Association saying that the decompression was “explosive” and that an attendant had suffered minor injuries.

One passenger, Vi Nguyen of Portland, said she woke up to a loud sound during the flight. She then saw a large hole in the side of the plane.

“I open my eyes and the first thing I see is the oxygen mask right in front of me,” said Nguyen, 22. “And I look to the left and the wall on the side of the plane is gone.”

“The first thing I thought was: ‘I’m going to die,’” he added.

Her friend Elizabeth Le, 20, said she also heard “an extremely loud pop.” When she looked up, she saw a large hole in the wall of the plane about two or three rows away, she said.

Ms. Le told that there was no one sitting in the window seat next to the missing fuselage, but that a teenager and his mother were sitting in the middle and aisle seats. Flight attendants helped them to the other side of the plane a few minutes later, she said. The boy appeared to have lost his shirt and his skin appeared red and irritated, she added.

“It was honestly horrible,” he said. “I almost broke down, but I realized I needed to stay calm.”

There were announcements over the public address system, but none were audible because the wind hitting the plane was so strong, he said. After the plane landed, paramedics came aboard to ask if anyone was injured, she added. A man sitting in the row immediately behind the hole said he had hurt his foot.

Ms Le said the passengers were not given an explanation of what had happened. In a video she took of the flight, she can hear passengers applauding after landing. “My God,” someone says.

After landing, Ms. Le told her that she and her friends would board another flight to Ontario that same night.

Alaska Airlines Flight 1282 took off for Ontario International Airport at 5:07 p.m. and was diverted back to Portland six minutes later, according to Flight reported, a flight tracking website. She reached a maximum altitude of about 16,000 feet, when her speed was recorded at more than 440 miles per hour, and she landed in Portland at 5:27 p.m.

The cause of the airborne problem was unclear until early Saturday morning. Keith Tonkin, managing director of Aviation Projects, an aviation consulting firm in Brisbane, Australia, said an excessive difference in air pressure inside versus outside the cabin could have caused the wall to break.

Passengers were probably able to breathe normally even when the plane was at its maximum altitude, Tonkin added.

The plane was new and had been certified in November, according to the FAA registration of aircraft. It entered commercial service that month and has since logged 145 flights, according to flight radar24another flight tracking site.

Representatives from Alaska Airlines, the FAA and the National Transportation Safety Board said they were investigating what happened.

Boeing said in a statement that it was “aware of the incident involving Alaska Airlines Flight 1282,” adding: “We are working to gather more information and are in contact with our airline customer.”

In 2018, Lion Air Flight 610, a 737 Max 8, crashed into the ocean off the coast of Indonesia, killing all 189 passengers and crew members. Less than five months later, in 2019, Ethiopian Flight 302 crashed shortly after taking off from the Ethiopian capital, Addis Ababa, killing all 157 people on board.

The Max planes were grounded after the second crash. Boeing made changes to the plane, including the flight control system behind the crashes, and the FAA cleared it to fly again in late 2020. In 2021, the company agreed to a $2.5 billion settlement with the Department of Justice. , resolving a criminal charge that Boeing conspired to defraud the agency.

In December, Boeing urged airlines to inspect all 737 Max planes for a possible loose bolt in the rudder control system after an international airline discovered a bolt with a missing nut during routine maintenance. Alaska Airlines said at the time that it expected to complete inspections of its fleet in the first half of January.

Mark Walker contributed with reports.