Alaska Airlines and United Airlines grounded all of their Boeing 737 Max 9 jetliners again on Sunday while they waited to be told how to inspect the planes to prevent another inflight blowout like the one that damaged an Alaska jet.
Alaska Airlines had returned 18 of its 65 737 Max 9 aircraft to service Saturday, less than 24 hours after part of the fuselage on another plane blew out three miles above Oregon.
The reprieve was short-lived.
The airline said Sunday that it received a notice from the Federal Aviation Administration that additional work might be needed on those 18 planes.
Alaska said it had canceled 170 flights — more than one-fifth of its schedule — by mid-afternoon on the West Coast because of the groundings.
A panel used to plug an area reserved for an exit door on the Max 9 blew out Friday night shortly after Alaska Airlines flight 1282 took off from Portland, Oregon. The depressurized plane, carrying 171 passengers and six crew members, returned safely to Portland International Airport with no serious injuries.
Southwest said its operations would be “unaffected,” as it doesn’t use that model of aircraft, and the other models of Boeing 737 Max jetliners don’t have the part that could cause the incident to happen.
“The MAX-8 aircraft in our existing fleet and the -7 in our future fleet do not have the exit door plug involved in the Friday evening event,” the airline said in a statement.
United Airlines said it had scrapped about 180 flights Sunday while salvaging others by finding other planes not covered by the grounding.
Between Saturday and Sunday night, 461 flights were delayed and 75 canceled at O’Hare, though it was unclear how many were due to the groundings. United Airlines declined to say how many of the canceled flights were out of O’Hare.
Alaska and United are the only U.S. airlines that fly the Max 9.
United said it was waiting for Boeing to issue what is called a multioperator message, which is a service bulletin used when multiple airlines need to perform similar work on a particular type of plane.
Boeing is working on a bulletin but had not yet submitted it to the FAA, according to a person familiar with the situation. Producing a detailed, technical bulletin frequently takes a couple of days, the person said. The person spoke on condition of anonymity because the company and regulators have not publicly discussed the process.
Boeing declined to comment.
Hours after the Alaska incident, the FAA ordered the grounding of 171 Max 9s including all those operated by Alaska and United until they could be inspected. The FAA said inspections will take four to eight hours.
Boeing has delivered 218 Max 9s worldwide, but not all of them are covered by the FAA order. They are among more than 1,300 Max jetliners — mostly the Max 8 variant — sold by the aircraft maker. The Max 8 and other versions of the Boeing 737 are not affected by the grounding.
U.S. Sen. Maria Cantwell, D-Wash., chair of the Senate’s Commerce, Science and Transportation Committee, said she agreed with the decision to ground the Max 9s.
“Safety is paramount. Aviation production has to meet a gold standard, including quality control inspections and strong FAA oversight,” she said in a statement.
Flight 1282 took off from Portland at 5:07 p.m. Friday for a two-hour flight to Ontario, California. About six minutes later, the chunk of the fuselage blew out as the plane was at about 16,000 feet. One of the pilots declared an emergency and asked for clearance to descend to 10,000 feet, the altitude where the air would have enough oxygen to breathe safely.
The aircraft involved rolled off the assembly line and received its certification two months ago, according to online FAA records. It had been on 145 flights since entering commercial service Nov. 11, said FlightRadar24, another tracking service. The flight from Portland was the aircraft’s third of the day.
The Max is the newest version of Boeing’s venerable 737, a twin-engine, single-aisle plane frequently used on U.S. domestic flights. The plane went into service in May 2017.
Two Max 8 jets crashed in 2018 and 2019, killing 346 people. All Max 8 and Max 9 planes were grounded worldwide for nearly two years until Boeing made changes to an automated flight control system implicated in the crashes.
The Max has been plagued by other issues, including manufacturing flaws, concern about overheating that led FAA to tell pilots to limit use of an anti-ice system, and a possible loose bolt in the rudder system.
Contributing: Kaitlin Washburn
