The day a piece of fuselage blew off a Boeing 737 MAX 9 midflight, Alaska Airlines engineers and technicians had scheduled a maintenance check for that aircraft.
The plane — which was on a flight from Portland, Oregon, to Ontario, California, when the piece blew out at 16,000 feet — experienced two warning signals related to its pressurization system in the days before the incident, as well as another warning the month before. In response, Alaska prohibited the plane from flying over large bodies of water and scheduled an overnight maintenance check for the evening of Jan. 5.
But, hours before the scheduled check, the fuselage piece blew out, leaving a gaping hole in the side of the aircraft.
The plane landed safely back at Portland International Airport, but the incident left many wondering how it could have happened and who is to blame. The National Transportation Safety Board is investigating the incident, and the Federal Aviation Administration is investigating Boeing’s quality control processes. The U.S. Justice Department has also opened a criminal investigation into the incident.
In the weeks since the blowout, most of the blame has fallen on Boeing and its supplier Spirit AeroSystems, a company based in Wichita, Kansas, that assembles the entire fuselage of 737 MAX planes finished at Boeing’s facilities in Renton.
But the safety check, which was first reported Tuesday by The New York Times, may renew scrutiny of Alaska. As described in The New York Times report, Alaska Airlines workers “were so concerned about the mounting evidence of a problem that they wanted the plane to come out of service … and undergo maintenance.”
A spokesperson for Alaska Airlines told The Seattle Times the maintenance plan and schedule for the aircraft was “in line with all processes and procedures.”
“Nothing required or suggested that the aircraft needed to be pulled from service,” the spokesperson continued. “Some maintenance work does require that — this is not one of those instances.”
The safety check was scheduled to look at the pressurization warning lights as well as a stiff handle on a passenger door.
Donald Wright, the vice president for maintenance and engineering for Alaska Airlines, told The New York Times the warning signals had come on twice in the preceding 10 days. The airline considers taking more aggressive action if the warnings are triggered three times in that time frame, Wright said.
“From my perspective as the safety guy, looking at all the data, all the leading indicators, there was nothing that would drive me to make a different decision,” Max Tidwell, the vice president for safety and security for Alaska Airlines, told The New York Times.
NTSB chair Jennifer Homendy said at the start of the agency’s investigation that she was not concerned about the pressurization warning lights, and that Alaska’s decisions to continue flying the plane while prohibiting it from over-ocean flights made sense.
Investigators would examine the pressurization logs, Homendy said in January, but “at this time, we have no indications whatsoever that this correlated in any way” to the fuselage blowout.
In an initial report, NTSB investigators found four bolts meant to hold the fuselage section in place were not reinstalled after being removed at Boeing’s Renton assembly plant. The fuselage section, a door plug, fills a hole in the fuselage in which an additional emergency exit can be installed.
The NTSB declined to comment on the report that Alaska had scheduled the aircraft for maintenance that night.
Alaska Airlines said Tuesday that the company remains “confident in our maintenance and safety actions leading up to the incident.
“We look forward to continuing our participation in a robust investigation led by the NTSB to ensure something like this never happens again,” the company said in a statement.
Citing interviews with the airline and records of the investigation into the blowout, The New York Times report said, “extensive evidence of a potential problem with the plane had been accumulated for days and possibly weeks.”
Mark Lindquist, a Tacoma-based attorney who is representing several Flight 1282 passengers in a lawsuit against Boeing and Alaska, told The Seattle Times that the coming court proceedings will reveal more information about what happened on that flight as well as the aircraft’s history.
The discovery will include “company records, maintenance records, interviews with employees from the techs to the engineers to the MBAs,” Lindquist said. “We’ll get reports that document what we’re hearing.”
