Transit Investigation
Recently, I worked as a TA at Tufts University where I instructed a class on Engineering Forensics focused on investigating transit accidents for planes, automobiles, and trains. Accidents were approached through a case-study method where I instructed students on error and risk analysis as well as the role of human performance, organizational culture, and government regulations in transit accidents. I also gained an understanding of FAA, NHTSA, and NTSB practices and regulations.
Through teaching that class, I created numerous case studies on various transit accidents including the Titanic, Air France 447, the Uberlingen Mid-Air Collision, and numerous crashes involving MBTA trains in Boston, and I also learned how to read through accident reports and quickly synthesize them.
The following is my brief analysis of Micah Endsley’s concept of Situation Awareness as well as how a loss of situational awareness led to the crash of American Airlines flight 965 in Cali, Columbia:
Part 1:
Mica Endsley defined situational awareness (SA) as the “perception of elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future,” and it has become the accepted definition across industries since. Endsley breaks the concept down into three levels of awareness; a merging highway vehicle can be used to illustrate these levels.
First, the driver perceives critical environmental elements in a timely manner: noticing the car driving in front of them with their left blinker on. Second, the driver would receive these stimuli and use contextual clues and prior knowledge to comprehend the situation: the driver ahead of them wishes to merge left. Finally, full SA is maintained by being able to predict the future state and actions of environmental elements, and prepare reactions: slowing down, allowing the car in front to merge left.
An important caveat is that SA cannot be gained once; individuals must direct constant attention towards remaining aware, focused, and cognizant to maintain SA. Spatial disorientation is commonly misattributed to a loss of SA in plane crashes, however spatial disorientation is only one of many symptoms of a loss of SA.
Part 2:
In American Airlines flight 965 into Cali, Columbia (CLO), two pilots lost situational awareness (SA) during their descent causing a controlled flight into terrain (CFIT). By investigating key moments in the final minutes of flight 965, system design improvements that will aid pilots in maintaining SA and prevent similar accidents in the future can be implemented.
When flight 965 was 60 miles from CLO, the ATC cleared them for Cali VOR, a radio system guiding planes on non-precision runway approaches; the ATC told the pilots to report crossing the TULUA waypoint. Possibly having misheard the instructions, the captain replied, “Cleared direct to Cali VOR,” and inputted a “direct-to” command into the flight management system (FMS). An error in this command also removed all remaining waypoints on their flightpath to CLO. This degraded the pilots spatial and situational awareness. They were unaware of their location in relation to key waypoints, and they failed to report crossing TULUA to the ATC, as they were unaware they had passed it. An existing update for the B-757 corrected this error, but flight 965 had not received it.
Another system improvement would be the standardization of airspace naming conventions. Colombian airspace names were not consistent with ICAO standards. First, the standard terminal arrival routes (STAR) for ICAO standards are named by their starting waypoint, but Colombian airspace delineates STARS by their final waypoint. Flight 965 was instructed to follow the ROZO 1. Another source of confounding error exists at this point when the pilots entered the ROZO 1, designated ‘R,’ into the FMS. Because Colombian airspace was out-of-date, another beacon designated ‘R’, ROMEO, existed 132 miles Northeast. The use of one code for two beacons displayed poor mode control, and it confused flight 965, as it explains their sudden left turn off the flight path towards ROMEO. Had Colombian airspace followed ICAO standards and named the STAR TULUA, this mixup would never have occurred.
Finally, the stick-shaker as the sole angle-of-attack (AOA) warning system in the cockpit prevents pilots from achieving maximum airplane performance. After the GWPS alert, the pilot pulled twice on the control column and twice activated the stick-shaker, indicating that the AOA was stall imminent. All transport planes should also include visual AOA indicators ensuring that pilots can fully maneuver planes in these situations; had the pilot held his grip despite the stick-shaker, the plane may have cleared the mountain ridge.
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