After more than a decade of experience with these advanced systems, operators and researchers are finding that the promise of improved flight safety is still largely unfulfilled. Some observers contend that increased automation may actually be creating new hazards. The automation issues which impact safety include flight crew workload, avionics failure modes, degradation of basic piloting skills, and incompatibilities of cockpit systems with the Air Traffic Control system.
Aviation researchers have discovered disturbing trends among the crews of the new generation of automated aircraft. Among those are aberrations in the ways in which flight crew workload is affected. Remembering that automation was supposed to reduce workload to free the crew to perform higher level tasks, they are finding that most workload reductions are occurring when work levels were already low, such as during cruise. As workload is decreased, there seems to be an insidious trend toward increased complacency, lack of vigilance and even boredom among the crews of highly automated aircraft. In historically high workload situations, such as departure and arrival, automated systems can actually increase crew activity, detracting from critical vigilance for outside traffic and awareness of position, terrain, and the general ATC situation.
As digital avionics were first being introduced, one of the advantages claimed for them was their easily recognized failure modes. Unlike electro-mechanical instruments, it was supposedly unlikely to have a difficult to detect, unannunciated failure. Digital logic simply would not permit it. In practice, errors in digital systems can be surprisingly subtle. As Dr. Earl L. Wiener (1988) describes using an alarm clock analogy, we have traded the potential for an undetected 5 or 10 minute error in setting the analogue alarm clock for a very precise 12 hour error (pm vs. am) in setting today’s digital alarms.
Recognition and recovery from automation failures can prove to be very difficult and involve very high workloads. The series of very slow, almost imperceptible, roll malfunctions experienced on Boeing 747s demonstrated that recognition and recovery can be slow and late. Another example involves a particular version of software on a leading transport that required five separate conditions to exist before a specific problem would manifest itself. Additionally, research has shown that many crews are reluctant to override an automatic system, even though there are obvious discrepancies in data being presented to the crew.
There is growing concern that automated systems can fail in ways that are both unanticipated and untrained. This difficulty in detecting system errors requires the crew to cross-check primary flight and navigation displays to ensure proper performance of the automated systems. This type of monitoring has the potential for giving new meaning to the concept of “Raw Data”. Crews are required to mentally “fly” the aircraft using raw data inputs as a monitoring technique for automatic systems.
Degradation of Basic Skills
There is growing, but still unsubstantiated, concern regarding degradation of pilot skills and proficiency through the use of extensive automation. Flight crew concern may be an effective counter to the development of problems in this area. Research (Wiener, 1992) shows that while a majority of pilots are concerned about skill deterioration when flying automated aircraft, only a minority believe their skills have been affected. Carefully designed standard operating procedures can play an effective role in maintaining proficiency in routine operations.
Incompatibilities with ATC System
While the cockpit is receiving a high level of attention from the makers of advanced avionics, the Air Traffic Control system has not escaped attention. Again, the rational is reduced workload, and improved safety, but the effects of ATC automation will ripple into the cockpit just as much as the reverse has already begun.
Among the systems ripe for conflict is the TCAS system. How does a flight crew respond when faced with a conflict between an ATC clearance and what his on-board TCAS commands? And worse, what other conflicts may be created in the effort to fly safely.