A terrifying scene unfolded on an Alaska Airlines flight bound from Portland, Oregon to Ontario, California on Friday night when a gaping hole suddenly opened up mid-air in the fuselage.

Alaska Flight 1282 departed PDX around 5 p.m. and was airborne for about 20 minutes when passengers reported hearing a “loud boom.”

“The oxygen masks dropped down, and I look to my left to hear and see wind blasting, with a piece of the wall gone,” Elizabeth Le told KTLA. “There was no one in the window seat but a mom and her teenage son were sitting [on] the aisle.”

Le said the mother apparently saved her son from getting pulled out of the plane.

“I looked up and saw that the son’s shirt was completely off and his skin was very red, most likely due to the cold air. I heard after from the son’s friend that the mom had to drag him back into the plane after the piece flew off,” she said.

The airline said that the pilot immediately turned around the Boeing 737 Max 9, which was carrying 171 passengers and six crew members, and returned to Portland where it landed safely.

FlightAware, a website that tracks flights, showed the jet reached an altitude of about 16,000 feet before descending rapidly and circling back to the airport.

“The safety of our guests and employees is always our primary priority, so while this type of occurrence is rare, our flight crew was trained and prepared to safely manage the situation,” Alaska Airlines said in a statement. “We are investigating what happened and will share more information as it becomes available.” 

The cause of the mishap was not immediately known, nor was the extent of any injuries.

The Federal Aviation Administration and National Transportation Safety Board are investigating, the airline said.

Ontario is located roughly 35 miles east of Los Angeles in the Southern California’s Inland Empire.