An article published today (October 2, '13) in the Times of London reported on the testimony of Michael Oakley, the coroner in the case of the crash of Air France 447 on June 1, 2009.
The inquest was told that the crew had no training on flying the plane manually at high altitude. The coroner stated that "The pilots were not adequately trained to handle the aircraft safely in the particular high altitude emergency situation that night" and "highlighted serious public concern of whether pilots are overly dependent on technology”.
This is a major point in my book Understanding Air France 447. Pilots who routinely fly the airplane only with the autopilot and flight director engaged (i.e., never without it), are ill prepared to take control when those systems are suddenly and unexpectedly unavailable. Any skill, from playing the piano, to manually flying heavy transport aircraft requires practice. Those skills degrade in measurable amounts when that practice is not performed. Those whose skills were never well established to begin with, are at even greater risk of failure to perform when that performance is required suddenly and unexpectedly.
Mr Oakley added: “This disaster highlights public concern of whether pilots are too dependent on technology and are not retaining the skills required to properly fly complex commercial aircraft.”
When a pilot's training and experience all center around always operating with the flight director, autothrottle, and autopilot engaged, he may never have had those skills in any meaningful way in the first place. I estimate that hand flying while still following a flight director relieves the pilot of 75% of the mental work of flying the airplane, and is not adequate preparation for a time when none of them are available. While we could perhaps at one time assume that any pilot qualifying on a heavy jet transport had thousands of hours of manual instrument flying experience, that is no longer true.
I am confident that this same theme will arise out of the investigation of Asiana 214, the Korean B-777 that crashed in SFO while executing a visual approach, slamming into the seawall prior to the runway threshold.
The coroner in the Air France case further stated that “The blockage of the tubes and the manner in which the stall alarm system ceased providing alerts at low speeds probably caused the pilots’ confusion and contributed to the accident.”
I find that contribution to be minimal, for the stall warning was unable to provide alerts for only 7 seconds of the 40 seconds of which the pitot tubes were clogged. The airplane climbed nearly 3000 feet, and lost about 100 knots of airspeed in the first minute. During this time, the proper time to stablize the airplane's attitude and simply maintain level flight, the stall warning functioned perfectly. As the airplane's angle of attack approached and exceeded the point of stalling, it sounded constantly for 53 seconds. Yet, during this time there was little stall recovery action from the crew other than to apply full power - which at that altitude is about as effective as simply hoping the airplane recovers. By the time the stall warning was intermittent, the situation was so extreme, that it would have required particular insight of the crew to recover. This is because the stall warning only became intermittent when the angle of attack exceeded about 45°( pitch attitude rarely exceeded 15° nose up). The airplane stalled as the angle of attack exceeded only 8°. They would have had to known to manually reduce the stabilizer trim, which had run to full nose up by that time. That stabilizer trim, however, is never used in normal flight on Airbus aircraft, nor is its position displayed.
Another important factor is the probably fatigue state of the crew. As outlined in the book, there is evidence to show that all three crew members were fatigued. As a result, their minimal manual flying skills were further diminished by a reduced mental capacity equivalent to an over-the-limit blood alcohol level. Combined with the startle effect of the sudden and unexpected change in the situation they became confused and unable to fly the airplane.
The article appears here: http://www.thetimes.co.uk/tto/law/article3884276.ece but requires a subscription to access the full text.