Alaska Airlines has canceled more flights as it awaits instructions from Boeing on how to carry inspections out on its fleet of 737 MAX 9 aircraft.
Before any of the grounded 737-9 jets can be safely flown again, following the Alaska Airlines plug door blowout on January 9, 2024, Boeing needs to provide a final Multi-Operator Message (MOM) setting out inspection details for the aircraft as approved by the Federal Aviation Administration (FAA).
On January 9, 2024, the FAA said that an initial MOM provided by Boeing was being revised after feedback from the United States (US) aviation agency.
On January 10, 2024, Alaska confirmed it was cancelling all 737 MAX 9 flights through to January 13, 2024, which equates to between 110 and 150 flights.
“We hope this action provides guests with a little more certainty, and we are working around the clock to reaccommodate impacted guests on other flights,” the airlines said.
In addition, Alaska said that before the aircraft type can operate again the FAA must publish an Alternate Methods of Compliance (AMOC) with “details for approval of operators’ inspection processes to ensure compliance with their Airworthiness Directive (AD)”.
Alaska also said it must provide its maintenance teams with “detailed inspection instructions and processes” developed by the airline so that staff can “conduct thorough inspections per the FAA’s specifications”.
On January 6, 2024, the FAA grounded 171 Boeing 737 MAX 9 aircraft after an Alaska Airlines jet suffered a plug door blow out 16,000 feet in the air, resulting in depressurization of the plane.
‘Quality escape’
Boeing CEO Dave Calhoun told CNBC on January 10, 2024, that a “quality escape” was at the heart of the 737-9 blowout, indicating that something was not built right or was missed that put the plane’s safety in jeopardy.
“What broke down in our gauntlet of inspections? What broke down in the original work that allowed for that escape to happen?” Calhoun said.
On January 8, 2024, both Alaska and United Airlines, the only other US carrier to ground 737-9s, said during inspections of their MAX 9 aircraft loose parts had been found on some door plugs fitted.
A source told Sky News that United Airlines had found nearly 10 planes with loose bolts during initial checks.
After initial inspections of the Alaska Airlines 737 MAX 9 involved in the incident, the National Transportation Safety Board (NTSB) Chair, Jennifer Homendy, said four bolts designed to help keep the plug door in place were missing.
The NTSB is trying to determine whether the bolts were ever fitted or somehow became loose before the incident.
“We have not yet recovered the four bolts that restrain (the plug) from its vertical movement, and we have not yet determined if they existed there,” NTSB engineer Clint Crookshanks said. “That will be determined when we take the plug to our lab in Washington, D.C.”