Alaska Airlines flight 1282, a Boeing 737-9, took off from Portland International Airport (PDX) at 17:06 Jan. 5 when it experienced a rapid decompression of the cabin shortly after takeoff. During the climbout, the aircraft’s mid-cabin door plug detached; the aircraft reached a maximum altitude of just over 16,000 feet before it was able to descend for a safe landing back at PDX at 17:26. There were no fatalities onboard the aircraft, though several injuries have been reported.
The Boeing 737-9 aircraft is part of Boeing’s 737 MAX fleet, though this model has an optional emergency exit door based on the passenger seating configuration chosen by the airline. On this particular aircraft, this optional door was not installed and instead was covered by a door plug. The current ongoing investigation by the US National Transportation Safety Board (NTSB) has reported the 12 stop fittings and various pins and bolts, which prevent the door plug from blowing out, became disengaged, allowing the door plug to blow out of the fuselage in-flight. Furthermore, the bolt guide tracks were found to be fractured, and the four bolts that restrain the door from vertical movement have yet to be found, leading investigators to question if the bolts were loose or not ever installed on the accident aircraft.
Safety Actions Taken following Boeing 737-9 Incident
After any accident or incident involving a commercial airline, the operator itself, as well as the US Federal Aviation Administration (FAA), typically requires aircraft groundings or mandatory safety actions to ensure the safety of the rest of the fleet of aircraft. As was the case with this accident, the FAA issued an Emergency Airworthiness Directive (EAD) on Jan. 6, preventing further flight of the Boeing 737-9 model airplanes with a mid-cabin door plug installed, until they have been inspected, and operators have taken proper corrective actions, which essentially has grounded the aircraft. The FAA cited the unsafe condition of the door plug is likely to exist or develop in other aircraft of the same type. The FAA can also issue additional requirements if the safety concern is determined to be more widespread than initial findings may indicate. The grounding currently impacts 171 Boeing 737-9 aircraft worldwide, though Alaska Airlines and United Airlines are the largest operators, the various other global airlines have announced they are adopting similar requirements to ground the planes and carry out safety inspections before allowing the planes to be put back into service.
The Investigation into Flight AA1282
The NTSB, through its investigations and scientific testing of the aircraft components, will determine whether the bolts were missing or loose on the door plug as well as why the accident occurred in order to prevent similar accidents from taking place. Following its investigations, the NTSB will issue a Preliminary Report, typically within a few weeks of the accident, followed by a Final Report of the findings and probable cause, though this report is typically issued between 12 to 18 months following an accident investigation. It is important to note, however, that the NTSB can issue safety recommendations and Safety Alerts at any point during an investigation if it is deemed necessary to immediately address an uncovered safety concern fleet-wide and allow for prompt correction by relevant stakeholders.
Alaska Airline (AS), United Airlines (UA) and The Boeing Company have also already issued statements to have found loose bolts or hardware during their initial inspections of the door plugs on similar aircraft and are taking steps to ensure compliance with the approved method of the FAA's EAD to return the aircraft to service.
Passenger Safety Concerns and Flight Disruptions
The FAA is responsible for leading efforts to inspect the Boeing 737-9 to prevent further or future incidents or accidents, as well as certifying the safety of the entire Boeing 737 MAX fleet. To date, the NTSB and the FAA have not issued any statements or findings correlating the current door plug issue to the broader overall safety of the Boeing 737 MAX fleet. Given previous fatal crashes and subsequent global groundings of the Boeing 737 MAX 8 model in 2019, as well as several other highlighted concerns with the MAX fleet, there is heightened concern among the flying public as to the safety of the overall aircraft fleet. This accident is likely to garner further inspections and raise awareness with regulators as to the safety of the aircraft and possible additional safety inspection requirements, though the findings of the investigation and preliminary report will likely play a significant role in any decisions for additional groundings.
In the short term, passenger disruptions have largely been limited to Alaska Airlines and United Airlines as the largest operators of the 737-9 worldwide. Given the approval of the inspection method and return to service requirements from the FAA issued Jan. 8, the related disruptions are likely to decrease over the coming week, dependent on findings uncovered during inspections.
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