The Boeing 737 Max 9 that had a door plug blow out over Portland, Oregon during an Alaska Airlines flight was scheduled for a thorough maintenance check the next day, according to the New York Times. The carrier’s engineers slated the aircraft to be taken out of service because of several hints at a problem that didn’t cross Alaska Airlines’ established threshold for an emergency grounding, which could have spotted Boeing’s critical quality control error.
Alaska Airlines has stated that a pressurization warning light on the Boeing 737 Max had turned on twice over the 10 days before the door blow out. If the light had turned on a third time, the plane would have been removed from service. The airline states that there isn’t any evidence that the warnings were related to the plug blowout, and a visual inspection didn’t show any door plug movement. Max Tidwell, Alaska’s vice president for safety and security, told the newspaper:
“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.”
Besides the door plug’s missing bolts, investigators found a bevy of evidence that Alaska Airlines completely overlooked. The National Transportation Safety Board found that the upward movement of the door plug over 154 flights left visible marks and could have created a gap. Passengers on previous flights told flight attendants of a whistling noise coming from the fuselage near the plug. The pilots were informed of the whistling but Alaska claims there’s no report of this.
Alaska’s engineers decided to schedule a maintenance check based on a predictive tool. Based on their recommendations, the plane was also restricted from long-haul flights over water. The airline could have avoided the nightmare flight and resulting lawsuit if it heeded warnings. The plug blowout could’ve been far worse. If a passenger were sitting in the seat by the plug, they could have been sucked out of the aircraft.
A version of this story originally appeared on Jalopnik.