In a shocking revelation, investigators from the National Transportation Safety Board (NTSB) have discovered that four bolts crucial to holding the door plug in place were missing during last month's blowout incident on Alaska Airlines flight 1282. The incident, which occurred on January 5, led to a 19-day emergency grounding of all Boeing 737 Max 9s in the United States and has reignited scrutiny of Boeing following the fatal Max 8 crashes in 2018 and 2019.

The NTSB's 19-page preliminary report, released on Tuesday, includes findings from a laboratory disassembly of the door plug recovered from an Oregon backyard after it fell 16,000 feet. The report states, "the observed damage patterns and absence of contact damage or deformation around holes associated with the vertical movement arrestor bolts and upper guide track bolts indicate that the four bolts preventing upward movement were missing prior to the incident."

Fortunately, all 171 passengers and six crew members onboard the flight returned safely to Portland International Airport, with no serious injuries reported. This finding corroborates reports by Alaska Airlines and United Airlines, the two US carriers operating the Max 9, which had previously identified loose bolts during inspections.

Despite the alarming discovery, NTSB Chair Jennifer Homendy emphasized that she would have no reservations about flying on a Max 9, stating that the issue is a complex one with multiple parts involved. The report, however, does not assign blame to Boeing nor provide a probable cause, aspects that will be included in the NTSB's final report expected to be released in a year or more.

The release of the preliminary report comes at a critical time for Boeing, as its quality control faces intense scrutiny. The Federal Aviation Administration (FAA) has deployed two dozen inspectors to the company's Renton, Washington plant for an agency audit. Boeing itself recently disclosed the need for "rework" on 50 incomplete 737 Max planes due to improperly drilled holes, causing a slowdown in deliveries. Boeing's fuselage contractor, Spirit AeroSystems, accepted responsibility for the issue.

The blowout of the door plug, which fills a space in the fuselage serving as an emergency exit when plane seats are arranged in a specific manner, prompted the FAA to ground all Boeing 737 Max 9s in the US for 19 days and announce significant changes to its oversight of commercial aircraft production.

The NTSB's preliminary report sheds light on the harrowing experience of the blowout. According to the report, the captain described a loud bang while climbing at approximately 16,000 feet. The impact caused the crew's ears to pop, and the captain's head was forcefully pushed into the heads-up display, almost dislodging his headset. The first officer's headset was completely removed due to the rapid outflow of air from the flight deck.

As the investigation continues, both the NTSB and FAA are committed to closely scrutinizing Boeing's operations. FAA Administrator Mike Whitaker acknowledged the shortcomings of the agency's previous oversight after the fatal 737 Max crashes in 2018 and 2019, expressing the need for additional steps to ensure sufficient oversight and necessary changes to the current system.

For now, FAA inspectors are actively monitoring Boeing's production lines, with a focus on Spirit AeroSystems' facilities, where the majority of the 737 Max fuselage is built. The FAA is reimagining its oversight processes and is expected to increase the number of inspectors to fulfil its commitment to promoting aircraft safety.

While the investigation is ongoing, the preliminary report's findings have unveiled a critical factor in the Alaska Airlines Boeing 737 Max 9 blowout, raising further concerns about Boeing's quality control procedures and prompting the industry to prioritize safety measures in aircraft production.