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Prescient’s Assessment of Boeing Door Plug Blowout

Disclaimer: The following assessment is based on investigations that Prescient Transmission Systems has performed for electric utilities that equip large power transformers with sudden pressure detectors. Although the industry is different, the technology is similar and worth discussing.


On January 5, 2024, a door plug blew out of Alaska Airlines Flight 1282, while the plane flew at 16,000 feet. The sudden depressurization caused oxygen masks to drop. Several items were pulled out of the plane, including cell phones, head rests, and clothing. Thankfully, no major injuries occurred.


This scary incident displays a lack of quality control and oversight when issues arise, especially given that Alaska Airlines was aware that the plane in question had pressurization issues. Let’s take a closer look at how these events played out, and what can be done to avoid future occurrences.


Timeline of Events


Alaska Airlines was aware that the plane in question had pressurization issues because the pressurization failure alert actuated several times in the weeks leading up to the January 5th incident. The following timeline outlines the short lifespan of the troublesome aircraft:


October 31, 2023 – Alaska Airlines receives new Boeing 737 Max 9 aircraft N704AL.


December 7, 2023 – First pressurization failure alert on aircraft N704AL. Flight crew flipped to the backup system and reported it. Maintenance tested and then reset the alert.


January 3, 2024 – Second pressurization failure alert on aircraft N704AL. Flight crew and maintenance responded in the same manner as the first alert.


January 4, 2024 – Third pressurization failure alert on aircraft N704AL. Flight crew and maintenance responded in the same manner as the first alert.


Before January 5, 2024 – Alaska Airlines restricted aircraft N704AL from flying over the ocean.


January 5, 2024 – Door plug blew out on Alaska Airlines Flight 1282, aircraft N704AL, during ascent over Beaverton, Oregon.


Hours later, Alaska Airlines grounded all Boeing 737 Max 9 aircraft in their fleet.


January 6, 2024 – The Federal Aviation Administration (FAA) grounded all Boeing 737 Max 9 aircraft temporarily.


A door-sized hole in the side of aircraft N704AL is visible in this image, released by the National Transportation Safety Board (NTSB).

A door-sized hole in the side of aircraft N704AL is visible in this image, released by the National Transportation Safety Board (NTSB).


What Led to the Door Plug Blowout?


Two key issues led to the door plug blowout on Alaska Airlines Flight 1282:


  1. Maintenance crews were unable to identify the problem that caused the pressurization failure alert to activate on aircraft N704AL during three previous flights.

  2. Alaska Airlines and Boeing management failed to address the problem with aircraft N704AL as the number of events increased.


Three alerts in less than 60 days should have grounded aircraft N704AL until Boeing and the FAA certified the airworthiness of the aircraft.


Recommendations to Avoid Future Occurrences


To avoid future occurrences with rapid depressurization, each primary and backup alert system must be designed so that sensors in both systems monitor cabin pressure in the same area. After the second alert in a specific aircraft, all pressure sensors should be removed and tested in a forensic lab to verify alert values. This will ensure that one sensor is not actuating erroneously.


Additionally, Prescient recommends the following actions be taken by the FAA, Boeing, and other aircraft manufacturers:


  1. The FAA must require all airlines to ground any aircraft that experiences more than one pressurization failure alert in thirty days.

  2. The aircraft manufacturer should be required to complete an investigation of the aircraft in question. They must certify the airworthiness of that specific aircraft.

    1. If the investigation cannot identify the reason for the alert in the aircraft, a minimum of 100 ascents and descents should be conducted, with no pressurization failure alerts actuated throughout, to certify airworthiness.

  3. The FAA should require third party investigations into aircraft with more than one pressurization failure alert in thirty days.

 

Require Root Cause Analysis Teams for Rapid Response


When investigating alerts with potentially serious ramifications for aircraft, the FAA must require the assemblage of a rapid response team with the express purpose of determining root cause. This team should be chaired by a senior manager who works in the safety assessment group, and include subject matter experts from engineering, reliability, and maintenance groups. Pilots who have been trained to respond to alerts should also be included.


The goal of this team is to uncover the root cause before a catastrophic event occurs. The rapid response team should be tasked with identifying corrective actions without considering the cost to manufacturers or airlines. Members of the rapid response team should be relieved of all other job assignments until the root cause has been identified and corrective actions are specified. If preliminary findings are not available within seven days, additional resources should be marshalled.


This Applies to Electric Utilities, Too


Catastrophic events are a risk for electric utilities, too. Warning signals are often activated before such events, but warnings are not always heeded. For electric utilities, warning signals may not be as noticeable as those in airplanes. They may be more subtle such as industry experts recommending that lockout relays need to be tested every ten years.


To ensure your system is prepared for the unexpected, or to have a forensic analysis completed after an incident, contact us. Our team at Prescient Transmission Systems specializes in physical security enhancements, wildfire risk reduction, and more, to ensure the electric energy grid is safe, reliable, and prepared for the future.

 

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