In this article, an aviation accident, made by United Airlines, will be taken as example. It is approved that human factors, especially the mental mood of the operator are very important key factors to deal with aviation problems.
It is suggest by research that human factors are the second biggest reasons to cause aviation accidents. Every system could have mistakes including aviation systems. When an aircraft has physical problem, human efforts are the only possibility to reduce or avoid the aviation disasters. However in some situations human factors, such as mental mood could result ever more serious disaster.
In 1989, July 19th, United Airlines flight 232 crashed in Sioux City Airport. There were 296 people on board, 184 of them survived, and 112 people are killed.
The accident started with physical system failure in the very beginning-a metallurgical defect in fan disc of tail-mounted engine. It caused a catastrophic disintegration, also engine’s accessory drive system was destroyed, and hydraulic control was lost. Moreover, shrapnel damaged No. 1 and No. 3 engines. At this stage hydraulic control was totally lost.
However, in the later investigation and analysis, it is believed that independent hydraulic system was the only chance, although the chance was very weak.
Hydraulic lines damage resulted that the crew had no control of the airplane. The crew cannot control rudder, elevators, flaps, slats, spoilers, or steering and braking of the wheels. However it is believed that the crew still takes control over the throttle controls of the two wing-mounted engines. If they vary the throttle controls, they still could control the plane in some degree. The experts had numbers of suggestions that the crew had further control of the plan, after the investigation and analysis, including cutting one throttle completely and increase the other.
There were 41 minutes between the engine failure and the crash. It seems to be a long time for the crew to react positively and find some ways which were suggested by experts later.
But the reality was the pilot and the co-pilot were struggling with the yoke, they could not control the throttles, they lost the capability to think and analyze as their mental mood caused by the dangerous situation.
Another pilot from DC was onboard as a passenger, he finally evolved the control operation, and he controlled the throttles and allowed the pilot and co-pilot to control the yoke, while the co-pilot made communications with the ground. When the plane crashed landing in the airport, the rescue teams were standby, many lives are save, but still 112 people are killed.
Discussion and Suggestions
In this case the third pilot involving was obviously violated on this flight. However, it benefited the control when the pilots were struggling in such attitude.
In additional, it is suggested that only knowledge pilot could keep their models valid and finally gave out some solutions. Thus, building and updating mental mood is a key step to diagnosis.
It is also suggested the better performances were built mental model sharing that the third pilot helped to established, and finally sharing by all the crew members. Thereore, the crew need to be always educated, that problems happen and every system will have problems and mistakes including aircraft systems. This education will make the crew imagine or predict what the problems will face to. When the real problem comes, the crew will have good mental mood.
Nevertheless,, the crew need to be trained all the time. The training should include how to deal the problems or system failures. The above case shows, only not the crew had a bed mental mood, but also they have less knowledge than the passenger pilot.
All-in-all, when the physical system failure, human effort can contribute huge to reduce the level of accident. Human mental mood is one of key factors. As in an invalid mood, the crew can do nothing. The valid mental mood can be re-establishes by one people in the group, and finally chaired by all the crew, they find a way to control the situation. Knowledge is a key factor to help the crew to re-establish a valid mental mood.
Besnard, D., & Greathead, D. (1991). A COGNITIVE APPROACH TO SAFE VIOLATIONS. Retrieved October 4, 2010 from http://www.dirc.org.uk/publications/techreports/papers/7.pdf : full source reference
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