Alaska Airlines Flight 1282 was a scheduled domestic flight operated by Alaska Airlines from Portland International Airport in Portland, Oregon, to Ontario International Airport in Ontario, California. Shortly after takeoff on January 5, 2024, a door plug on the Boeing 737 MAX 9 aircraft blew out, causing an uncontrolled decompression of the aircraft. The aircraft returned to Portland for an emergency landing. All 171 passengers and six crew members survived the accident, with three receiving minor injuries. An investigation of the accident by the National Transportation Safety Board (NTSB) is ongoing. A preliminary report published on February 6 said that four bolts, intended to secure the door plug, had been missing when the accident occurred and that Boeing records showed evidence that the plug had been reinstalled with no bolts prior to the initial delivery of the aircraft.
Aircraft and crew
The aircraft involved in October 2023
The aircraft involved was a Boeing 737 MAX 9 (typically referred to as model 737-9 in official FAA documents) with manufacturer's serial number 67501, fuselage line number 8789, and registered as N704AL. It was around two months old at the time of the accident.[2][3] At the time of the accident, the aircraft had logged 510 total flight hours over 154 flights.[4]
737 MAX 9 comparison
Door installed
Opening plugged
A comparison of the 737 MAX 9 with and without the rear mid-cabin exit door
The MAX 9 has optional rear mid-cabin emergency exit doors, on each side of the aircraft behind the wings. Aircraft configured with greater than 189 seats, such as the MAX 9s operated by Lion Air (220 seats) and Corendon Dutch Airlines (213 seats), require these additional emergency exit doors and slides to meet regulatory requirements for evacuation speed. On aircraft with less dense configurations, such as those operated by Alaska Airlines (178 seats) and United Airlines (179 seats), the doors are not required and plugs are installed in their place.[5] Compared to leaving the exit door in place, the plug is lighter, offers a full-sized passenger window, and does not have the complexity of a door with its operations and maintenance concerns.[4] On the interior of the aircraft, the plugs are covered with cabin panels no different in appearance from a regular window panel.[6][7]
The door plug was manufactured by Spirit AeroSystems in Malaysia on March 24, 2023. It arrived at Spirit's factory in Wichita, Kansas, on May 10, where the fuselage was assembled. It was installed on the fuselage before it was shipped by train on August 20 for final assembly at the Boeing Renton Factory in Renton, Washington, where it arrived 11 days later.[4][8]
After the fuselage arrived at the Boeing Renton Factory, five damaged rivets were found on the fuselage near the door plugs. The plug was removed so that Spirit AeroSystems employees could fix the rivets. Once the repair was made, the door was reinstalled, but not bolted into place.[4]
From November 27 to December 7, the aircraft was under modification by AAR Corp at a facility in Oklahoma City to install a satellite antenna for in-flight internet service atop the rear fuselage, in the vicinity of the door plugs. AAR stated on January 8 that they did not perform any work involving the plugs themselves.[9][10]
The unnamed captain had logged 12,700 flight hours, including 6,500 hours on the Boeing 737. The first officer, Emily Wiprud,[11] had 8,300 flight hours, with 1,500 of them on the Boeing 737.[4]: 2
As of June 28, 2024, Alaska returned the accident aircraft to Boeing, which is listed as the owner on the formalized aircraft registration, while awaiting delivery of a MAX 10 aircraft.[12]
Accident
Flight path illustration of Alaska Airlines Flight 1282
Approximately six minutes after takeoff, the factory-installed door plug filling the port-side opening for the optional emergency exit door separated from the airframe, causing an uncontrolled decompression of the aircraft.[6][15] The aircraft's oxygen masks deployed during the accident.[13] No one was in seat 26A, which was immediately next to the hole.[16] Three passengers experienced minor injuries that required medical attention, and some passengers' items were lost when the items were sucked out of the opening.[14][17][18]
A teenage boy seated in row 25 had his shirt ripped off and blown out of the aircraft; his mother said she had to hold onto him to prevent him being blown out during the decompression.[19][20] Passengers reported hearing a loud bang followed by the oxygen masks deploying and a large, loud gust of wind.[21] One passenger said that others closer to the opening in the plane were able to move to other seats further away.[22]
Interior view from after the accident showing the missing door plug and damaged seats
The decompression event caused the cockpit door to fly open and hit the lavatory door, which initially became stuck.[23] After several attempts, a flight attendant was able to close the cockpit door.[23] The cockpit door is designed to open in the event of an uncontrolled decompression, but the crew was not aware of this.[24] The laminated Quick Reference Checklist stowed below the cockpit windows was blown into the cabin.[23] The first officer's headset was pulled off, and the captain's was dislodged.[23]
Interior non-structural damage was observed at rows 1 through 4, 11 and 12, 25 through 27, and 31 through 33, including damage to seat 25A, which lost its headrest and was itself twisted, and seat 26A, which lost its headrest and seatback cushion as well as the tray table on its rear side.[23]
According to flight trackers, the aircraft had climbed to about 16,000 feet (4,900 m) when the accident occurred.[25] The pilots made an emergency descent to 10,000 feet (3,000 m) and returned to Portland,[26][6] where they successfully made an emergency landing at 5:27 pm.[13] Firefighters boarded the aircraft to check for injuries among the passengers.[26]
Flight data recorder timeline
At a media briefing on January 8, the NTSB provided the following timeline of key events obtained from the flight data recorder.[24][4]
5:12:33 pm – While passing 14,830 feet (4,520 m), recorded cabin pressure drops from 14.09 to 11.64 psi (97.1 to 80.3 kPa); "cabin altitude >10,000 feet warning" activates, indicating that the cabin is underpressurized at an altitude greater than 10,000 feet (3,048 m) above sea level; pressurization or supplemental oxygen is necessary above that altitude
5:12:34 pm – Master caution activates; cabin pressure continues to drop, recorded at 9.08 psi (62.6 kPa)
5:12:52 pm – Master caution deactivated by crew
5:13:41 pm – Aircraft reaches a maximum altitude of 16,320 feet (4,974 m) and begins to descend
5:13:56 pm – Autopilot selected altitude changes from 23,000 to 10,000 feet (7,010 to 3,048 m)
5:14:35 pm – Master caution activates again for three seconds
5:16:56 pm – Aircraft begins a left turn, heading north back to PDX
5:17:00 pm – Aircraft descends below 10,000 feet (3,048 m)
5:18:05 pm – While passing 9,050 feet (2,758 m), "cabin altitude >10,000 feet warning" deactivates; cabin pressure recorded at 10.48 psi (72.3 kPa)
5:26:46 pm – Aircraft lands back on runway 28L at PDX
Aftermath
Alaska Airlines initially grounded their 737 MAX 9 fleet of 65 in the hours after the accident on January 5.[6] The airline later said that 18 aircraft were ready to return to service on January 6 after determining that those 737 MAX 9s had already had their door plugs inspected "as part of a recent heavy maintenance visit".[14] However, later in the day, on January 6, the Federal Aviation Administration (FAA) issued an Emergency Airworthiness Directive (EAD) that grounded all Boeing 737 MAX 9 aircraft with a mid-cabin door plug installed, pending a required inspection and corrective actions where required.[27][15] Alaska Airlines subsequently removed the 18 aircraft from service following the EAD.[14] The EAD also impacted United Airlines and Copa Airlines of Panama, which operate the MAX 9 in the United States.[28][29]Turkish Airlines of Turkey and Lion Air of Indonesia also grounded their fleets for inspection.[30] On January 7, the European Union Aviation Safety Agency (EASA) adopted the FAA's EAD, though it stated that no airline in its jurisdiction currently operated any MAX 9 aircraft with the door plug configuration.[31]
The cabin door plug was discovered in the backyard of a home in the Cedar Mill area, near Oregon Route 217.[32][33] It was reported to the NTSB on January 7.[34] Two mobile phones from the flight had also been found by members of the public, one in a backyard and the other by a road.[35]
On January 12, Alaska Airlines announced further cancellations through Tuesday, January 16, equating to between 110 and 150 flights per day. On January 17, Alaska Airlines announced that their maintenance and engineering technicians had completed preliminary inspections of "a group of our 737-9 MAX" planes as requested by the FAA and had provided the data to Boeing and FAA for further analysis and consultation. Flight cancellations were extended to Sunday, January 21.[14]
On January 21, the FAA recommended inspections of door plugs on the Boeing 737-900ER, an earlier non-MAX 737 version that uses the same type of door as the accident airplane. The FAA said inspections should "ensure the door is properly secured." The agency said some operators doing inspections on those aircraft "noted findings with bolts during the maintenance inspections." The FAA said the 737-900ER has 11 million hours of operation and has not had problems with its door plugs. In the United States, Alaska, Delta, and United fly the 737-900ER.[38][39]
On January 24, the FAA approved a new inspection process and cleared all 737 MAX 9 aircraft with door plugs to return to service when the inspection is completed successfully for each plane.[40] Alaska Airlines and United Airlines began returning their 737 MAX 9 planes to service on January 26 and 27, respectively.[41][42]
Alaska Air Group reported in April 2024 that Boeing had paid about US$160 million as initial compensation to address the hit from the temporary grounding of 737 MAX 9 jets.[43] The compensation package also included allowing Alaska to return the aircraft involved to Boeing, reducing storage and maintenance costs for the airline.[44][45] Across all MAX 9 customers, Boeing agreed to pay a total of US$443 million to compensate them for losses during the grounding.[46] To bring 737 fuselage construction back in-house, Boeing announced on June 30 that it would buy back Spirit AeroSystems in a US$4.7 billion deal expected to close in mid-2025.[47][48]
Investigation
NTSB investigators with the door plug recovered from the backyard of a home in Cedar Mill, Oregon
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.[51] On each occasion of a fault, the alternate controller was used, and flights proceeded normally.[23] 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.[23] It is not yet known if the indicator warning is related to the accident; the NTSB investigation will include the issue.[23]
January 8, 2024: NTSB Chair Jennifer Homendy briefing the media in Portland, Oregon, on the NTSB investigation involving Alaska Airlines Flight 1282
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.[23] 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.[52]
On January 8, United Airlines stated they had found loose bolts during inspections on an undisclosed number of grounded aircraft.[53] Alaska Airlines also announced their inspections had found loose bolts on "many" aircraft.[53][54]
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 for full transparency and cooperation in the investigation with the NTSB and FAA.[55][56] 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.[57] 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.[58]
NTSB staff examine the door plug in the NTSB materials laboratory
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.[24] The upper guide fittings on the door plug were found to be fractured.[24] Investigation on the status of the retention bolts designed to prevent the door plug from moving upwards is 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 are trying to determine if the bolts were never installed or if they were torn off when the door plug blew out.[9] The NTSB will also examine witness marks using microscopes and other scientific equipment.[24]
On January 15, in a message to employees, Boeing Commercial Airplanes President and CEO Stan Deal announced "immediate" actions the company is 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.[needs update] These actions are separate from the FAA's investigation and the agency's plan to increase oversight of 737–9 production.[59]
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.[4]
The NTSB held an investigative hearing on the accident on August 6-7.[60][61] 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.[62][63] Boeing responded that this was standard practice.[64]
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.[65][66]
The NTSB released their investigation docket and held a public hearing on August 6.[3][67]
^Gates, Dominic; Cornwell, Paige (August 25, 2024). "Inside Boeing's factory lapses that led to the Alaska Air blowout". The Seattle Times. The following detailed account... is compiled from the transcripts of federal investigators' interviews of a dozen Boeing workers, synchronized with an internal Boeing document obtained by The Seattle Times that tracked day-by-day the rework that led to the door plug lapses.
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