(AP) — Alaska Airlines again grounded all of its Boeing 737 Max 9 jetliners on Sunday after federal officials indicated further maintenance might be required to ensure that another inflight blowout like the one that damaged one of its planes doesn’t happen again.
The airline had returned 18 of its 65 737 Max 9 aircraft to service on Saturday following inspections that came less than 24 hours after a portion of one plane’s fuselage blew out three miles (4.8 kilometres) above Oregon on Friday night.
The depressurised plane, which was carrying 171 passengers and six crew members, returned safely to Portland International Airport with no serious injuries.
The airline said in a statement that the decision was made after receiving a notice from the Federal Aviation Administration that additional work might be needed.
Other versions of the 737 are not affected.
“These aircraft have now also been pulled from service until details about possible additional maintenance work are confirmed with the FAA. We are in touch with the FAA to determine what, if any, further work is required before these aircraft are returned to service,” the airline said.
The FAA had ordered the grounding of some 737 Max 9s on Saturday until they could be inspected, a process that takes about four hours. The world’s airlines are currently operating about 171 737 Max 9s globally.
The aircraft make up about 20% of the Alaska Airlines’ fleet. As of midday, Alaska had cancelled about a fifth of its Sunday flights, according to FlightAware.com. United Airlines, which also grounded its Max 9s, had about a 10% cancellation rate on Sunday.
The National Transportation Safety Board is investigating Friday’s accident and is still looking for the door from the panelled-over exit that blew out. Some planes, due to smaller capacity, panel over what would have been an exit door.