Alaska Airlines Flight 1282

Investigation

The National Transportation Safety Board (NTSB) conducted an investigation into the accident, led by NTSB Chair Jennifer Homendy. The FAA, Alaska Airlines, the Air Line Pilots Association (the union representing Alaska pilots), the Association of Flight Attendants (the union representing Alaska flight attendants), Boeing, Spirit AeroSystems, and the International Association of Machinists and Aerospace Workers (the union representing Boeing and Spirit AeroSystems workers) provided support as members of the investigation party. The United States Department of Justice (DOJ) and Federal Bureau of Investigation (FBI) have also opened separate criminal investigations into the accident.

The aircraft involved in the accident had its cabin pressurization "AUTO FAIL" indicator illuminated on three previous occasions – on December 7, January 3 (in flight), and January 4 (after landing). This indicates that the primary automatic cabin pressurization controller was disabled by a fault condition, which can be caused by a problem with the controller itself, one of the valves it controls, an excessive pressure differential, an excessive rate of cabin pressure change, or a high cabin altitude. When a fault is detected, pressurization control automatically transfers to an alternate automatic controller. The "AUTO FAIL" indicator alerts the crew to this change, but no intervention is prescribed. On each occasion of a fault, the alternate controller was used, and flights proceeded normally. However, due to the faults, Alaska Airlines had restricted the aircraft from operating extended overwater flights (under ETOPS rules) until a detailed maintenance inspection could occur. NTSB concluded that this indicator was not related to the accident.

The cockpit voice recorder (CVR) was overwritten after the accident. The CVR on the aircraft records a two-hour loop, and the circuit breaker in the cockpit was not pulled to stop the recording after the aircraft landed. NTSB chair Jennifer Homendy subsequently called for extending capacity to 25 hours, rather than the currently mandated two hours, on all new and existing aircraft. If implemented, the new rule will align with International Civil Aviation Organization (ICAO) and European Union Aviation Safety Agency's (EASA) current regulations.

On January 8, United Airlines stated they had found loose bolts during inspections on an undisclosed number of grounded aircraft. Alaska Airlines also announced their inspections had found loose bolts on "many" aircraft.

On January 9, Boeing's president and CEO, Dave Calhoun, acknowledged the company's mistake in a company-wide meeting on safety and transparency following this accident. The company pledged full transparency and cooperation in the investigation with the NTSB and FAA. In an interview with CNBC on January 10, Dave Calhoun described it as a quality control issue and said that a "quality escape" had occurred. Also on January 10, the FAA notified Boeing that it was under investigation for "alleged noncompliance" with regulations relating to new aircraft inspection and testing.

The NTSB's initial assessment found that the stop pads and fittings of the door plug and frame were intact, and that the plug had moved upwards to clear the pads to enable its ejection from the aircraft. The upper guide fittings on the door plug were found to be fractured. Investigation on the status of the retention bolts designed to prevent the door plug from moving upwards was ongoing. By design, four retention bolts should be present; Homendy said the bolts were not on the door plug when it was found. She said investigators were trying to determine if the bolts were never installed or if they were torn off when the door plug blew out. The NTSB also examined witness marks using microscopes and other scientific equipment.

On January 15, in a message to employees, Boeing Commercial Airplanes President and CEO Stan Deal announced "immediate" actions the company was taking to bolster quality assurance and controls in 737 production: planning more quality inspections, planning more team sessions on quality, Boeing review of Spirit AeroSystems work, airline oversight inspections and independent assessment by outside party on Boeing's quality management system. These actions were separate from the FAA's investigation and the agency's plan to increase oversight of 737–9 production.

The NTSB released a preliminary report on the accident on February 6, which said that the damage patterns on the door plug indicated that the four bolts, intended to secure the door plug, had been missing when the accident occurred. They also reviewed Boeing records that showed evidence that the plug had been installed with no bolts.

The NTSB held an investigative hearing on the accident on August 6–7. On March 13, NTSB chairman Homendy stated in a letter to Congress that security footage of the aircraft's door plug installation back in September had been overwritten. Boeing responded that this was standard practice.

After Boeing revealed privileged information about the investigation to journalists during a meeting on June 25, along with analysis of the facts, the NTSB stopped sharing information with the company.

The NTSB released their investigation docket and held a public hearing on August 6. A second hearing on June 24, 2025, found that the probable cause of the accident was the blowout of the door plug, attributing this to Boeing's failure to adequately oversee its factory workers.