Alaska Airlines Flight Continued Operations Despite Scheduled Safety Check Before Door Incident

An Alaska Airlines Boeing 737 Max 9 continued to fly with passengers despite engineers’ concerns and a scheduled maintenance check due to warning lights, right before a door plug detached mid-flight on January 5. The incident, which happened en route from Portland to Ontario International Airport, California, brought Boeing’s manufacturing processes and airline safety procedures into sharp focus.

Interviews and documents revealed that the airline had planned to pull the aircraft from service for maintenance on the evening of January 5, after engineers had raised alarms about the aircraft’s pressurization system warning lights. However, the plane was kept in operation to complete its scheduled flights, ending in Portland, Oregon, where Alaska Airlines has a maintenance facility. Before reaching its final scheduled flight for maintenance, the door plug was lost at 16,000 feet, leading to an emergency but safe landing.

The decision to continue operations until the plane reached the maintenance facility highlights the airline’s reliance on a predictive tool over the threshold for taking immediate action based on the warning signals. Alaska Airlines confirmed the events but maintained that the indications did not warrant the immediate grounding of the plane. According to Donald Wright, Vice President for Maintenance and Engineering at Alaska Airlines, the warning lights had activated twice in the prior ten days, below the airline’s threshold for more decisive action.

Alaska Airlines imposed restrictions on the aircraft following engineers’ advice, limiting its operations to avoid long-haul overwater routes. This precaution was taken to ensure proximity to emergency landing sites if needed.

The door plug’s loss has led to intensified scrutiny over the airplane’s condition in the days leading up to the incident. The National Transportation Safety Board’s preliminary report indicated that missing bolts intended to secure the door plug were a contributing factor. This detail, along with visible upward movement marks on the door plug observed over 154 flights since the aircraft’s service commencement in fall, suggested accumulating evidence of an issue.

The maintenance and inspection timeline raises questions about whether different inspection approaches could have integrated various warning signs to prevent the incident. Mark Lindquist, representing passengers from the January 5 flight, emphasized the concern over the airline’s decision to continue operations despite engineers’ caution.

In addition to the Jan. 5 event, Alaska Airlines confirmed a separate issue with the plane’s pressurization system triggered warning lights on prior flights, including one on January 3, leading to inspections but no immediate action. The airline asserted its commitment to safety, stating no records of reports related to a whistling noise passengers allegedly heard on a previous flight.

As investigations continue, the sequence of decisions leading up to the door plug detachment incident underscores the complex interplay between maintenance protocols, predictive tools, and safety thresholds in airline operations.

Sources: AirGuide Business airguide.info, bing.com, nytimes.com