A German Airbus is controlled mainly by on-board computers that are designed to do just about everything that used to be the responsibility of the pilot -- maintaining level flight, warning of overspeed, signaling when the airplane is too close to the ground.
This Airbus was on a test flight and the computers worked very well except for one two instances of human error. On each side of the fuselage there are small units that indicate the airplane's angle of attack -- whether the airplane is flying nose up or nose down. The devices, which resemble small levers, must be moveable. In the case of this accident, they were filled with water because the airplane had just been washed down with a fire hose and, at altitude, they froze in position that sent signals to the central computer to climb at a steep angle.
The angle was too steep. The pilots overlooked a warning on their primary instrument panel that trim tabs needed adjustment to overcome the airplane's angle of attack.
Two human errors -- washing the plane instead of cleaning it with a cloth, and not noticing the directions on the control panel -- and the Airbus with seven people aboard lost flight speed and crashed into the Bay of Lion, killing all aboard.
In effect, what happened is that the computer "realized" that the information from the units measuring angle of attack were in conflict with the other information it was receiving, and it notified the pilots that certain corrective measures needed to be taken.
The investigating teams, in this case French, continue to astonish me with their thoroughness. They go through the usual suspect like weather one by one in order to eliminate them. Then, if they find the proximate cause of the crash, A, they don't stop there. They ask why condition A existed. Then, if they find that B was responsible for A, they investigate the cause of B -- and so on until all available data on contributory variables are collected and analyzed. Amazing stuff.
This Airbus was on a test flight and the computers worked very well except for one two instances of human error. On each side of the fuselage there are small units that indicate the airplane's angle of attack -- whether the airplane is flying nose up or nose down. The devices, which resemble small levers, must be moveable. In the case of this accident, they were filled with water because the airplane had just been washed down with a fire hose and, at altitude, they froze in position that sent signals to the central computer to climb at a steep angle.
The angle was too steep. The pilots overlooked a warning on their primary instrument panel that trim tabs needed adjustment to overcome the airplane's angle of attack.
Two human errors -- washing the plane instead of cleaning it with a cloth, and not noticing the directions on the control panel -- and the Airbus with seven people aboard lost flight speed and crashed into the Bay of Lion, killing all aboard.
In effect, what happened is that the computer "realized" that the information from the units measuring angle of attack were in conflict with the other information it was receiving, and it notified the pilots that certain corrective measures needed to be taken.
The investigating teams, in this case French, continue to astonish me with their thoroughness. They go through the usual suspect like weather one by one in order to eliminate them. Then, if they find the proximate cause of the crash, A, they don't stop there. They ask why condition A existed. Then, if they find that B was responsible for A, they investigate the cause of B -- and so on until all available data on contributory variables are collected and analyzed. Amazing stuff.
