The German Wings 4U9525 tragedy is now leading to a discussion on whether and how depressive and suicidal tendencies of a pilot can be screened for, which in turn is leading to a discussion of what occupations should or could be forbidden to those having such tendencies. And what degree of disability is disabling for an occupation is the question that follows. Many military and law enforcement bodies do have such bans. In some US states you can’t pass the bar exams if you have been diagnosed as depressive. (But you can continue to practice if you become depressive the day after you pass your bar exams). Should a person with suicidal tendencies be permitted to become a President or a Prime Minister or a Finance Minister? or a surgeon or a hedge fund manager for that matter?
Every human has some bouts of some level of depression. I am sure psychological profiling has become very sophisticated and can be very successful in general screening. I have even used such profiling – albeit very crudely – when screening applicants for a job. If one applied the precautionary principle – which is about the most unscientific mumbo-jumbo as can be found – very few would ever be deemed suitable for any sensitive occupation. I cannot see that psychological testing will ever eliminate all potential cases of determined, suicidal pilots. It will also give many false positives.
I suspect that the solution lies not in expecting psychological profiling to find the “needle in the haystack” but in ensuring that even if he appears he can do no harm. The regulation for always having two people in the cockpit goes down that road. It is said that for commercial flights today the pilots spend only about 5 minutes actually flying the plane themselves. And much of that time is spent in plugging in what George, the autopilot, is supposed to do. Most of their time is spent in monitoring and checking systems rather than actively flying. In theory, apart from taxiing before take-off and after landing, George could fly the entire flight. His side-kick Mary – if she was present – could do all the monitoring that pilots currently do. George would fly and Mary would – independently – provide the checks.
Coming from the power generation world I am familiar with all the “forbidden modes of operation” that are embedded within the control systems of gas and steam turbines to avoid zones of dangerous vibration or even of operating at “uneconomic” conditions. Once open a time – 100 years ago – measurements were physically monitored by operators. A very few mechanical – but automatic – governors were used, for example to restrict turbine overspeed (by restricting flow). Later – but before the electronic age – physical measurements were converted into electrical signals, displayed in control rooms and provided the operator with many, many alarms of potentially dangerous conditions. Some operating modes were automatically avoided by these measurement signals leading to the corrective operation of motorised valves. Now in the electronics age and with the speed of computing that is available, it is software in the control system – which the operator cannot override – which takes care of “enforcing” the avoidance of the most dangerous forbidden zones.
Pilotless drones are booming. Pilotless commercial planes are not yet in use not because of technical barriers but because of lack of acceptance by passengers and by society in general. Cargo planes are not pilotless yet, but only because of the concerns of air traffic control and airports and of those under the flight-path. But pilotless planes will surely come (even if pilots’ unions will not much care for this). No doubt pilotless planes will pose new challenges such as the avoidance of hacking or some unauthorised assumption of control. But these are all technical, technology, system and societal challenges rather than insurmountable barriers. No technology breakthroughs or invention of new materials are required for introducing the use of pilotless commercial aircraft.
But as a first step maybe George could enforce avoidance of some forbidden modes of flying even with a suicidal pilot at the controls. We may well see that the “Terrain, terrain!” warning will become obsolete. George (and Mary) would have taken over control of the aircraft long before the proximity warning alarms go off.