Investigators recovered the wheels down indicator light from the crash site and found that the bulbs in it were burnt out. The tiny bulbs had led to a major disaster. 103 people died.
It was likely that the pilot (s) might have inadvertently bumped against the control column ( the aircraft equivalent of a steering wheel of a car ). They might not have noticed it happening. The autopilot was designed to deactivate in a certain way whenever the control column was moved. Once deactivated , the autopilot would have stopped keeping the aircraft at the set level of 2000 feet and it would have allowed the plane to descend.
The cockpit had a many instruments that would have indicated the descent. There were altimeters (which showed height) , vertical speed indicators ( which showed how quickly the aircraft was descending) and other instruments that would have told them immediately that all was not right. Unfortunately, preoccupation with the indicator light made them not see these instruments just inches away from them.
Most accidents do not occur due to one single error or event. Usually a chain of errors / events are responsible, and if any one link of the chain was broken ,the accident would not have happened. Flight 401 would not have crashed if the bulbs did not burn out, if the back up system of checking the wheel was successful , if the radar air traffic controller warned them , if they heard the alarms , and so on .
But most fundamentally , the crew did not use their resources well. The indicator light did not need the attention of all three crew members. One of the pilots should have been clearly in command , flying and monitoring the aeroplane. In this instance , none of the crew monitored the autopilot which gradually flew them into the ground. One glance at some of the instruments would have alerted them about the descent and the error chain would have broken.
The Tristar L 1011 was a very modern aircraft for its time and had an high level of automation which might have contributed to the accident. Today , automation has increased tremendously in aviation and other fields such as medicine. Unfortunately , when the automation is reliable most of the time , one starts to trust it completely , become complacent , and stop monitoring its function. Then when the automation fails disaster strikes. It is important when using automation to understand its behaviour in various situations, its limitations , and to monitor its functioning.
There are important lessons from Flight 401for all in aviation (cockpit crew resource management) , medicine (specially anesthesia crisis resource management) , and other specialties.
It is beyond the scope of this website to do a detailed analysis of this crash as accident investigation and crew resource management are very specialised areas. There are plenty of resources on and offline for a deeper understanding of these topics. Also, if you detect any errors , please let me know via the contact link at the top of the page.
The faults made in Flight 401 seem quite silly and avoidable. However, with the magic of hindsight , most mistakes appear that way. The crew of Flight 401 were highly experienced , but did not have the luxury of leisurely analysing their last ten minutes of their life. Thus, it is not the intention of this website to disrespect the crew.
There is an interesting sideshow to this story. After the crash, people reported seeing ghosts of the Captain and Flight Engineer in other aircraft of the airline. This led to a book and a TV movie on the issue of ghosts of Flight 401. When Flight 401 crashed , sections of the aircraft survived the impact. Parts were salvaged from these and were installed in other aircraft and this may have fuelled the ghost stories. If you do a search on the net about Flight 401 and ghosts , you would be surprised at the number of hits that turn up.
Finally , please note that aviation is an extremely safe form of transport. You have a much higher chance ( this is not a joke ) of dying from a road traffic accident on your way to the airport than dying from a crash during the subsequent flight of many thousand miles.
Modern aircraft such as this Airbus are heavily automated. Computer screens replace the hundreds of dials seen in older aircraft such as the one involved in Flight 401 . Automation can tremendously increase safety provided one knows how to use it , knows its behaviour, monitors its function , and is aware of its limitations. (Photo copyright Airbus)
