Human factors.
Gents, with an alarmingly high frequency, I see posts with questions about technicalities of A-330 wizz by on PPRUNE.
Let me reiterate that within weeks of finding the recorders of AF447, the BEA issued an interim report in which they stated, in street language, well, the recorders told us nothing that we did not suspect already, from ACARS messages, wreckage investigation and such. For now, we will spend a year to study human factors, which appear to be the dominating factor in the accident.
Let me illustrate the overwhelming power of the human mind with the following quote, from Airliner, issue 1996 Quarter 2 (Airliner is a Boeing publication, the predecessor of today's AERO magazine).
Quote:
Case Study #1.
It is just after 10:00PM local time. The crew receives a departure clearance from an air traffic controller who uses non-standard phraseology. The crew doesn't fully understand the clearance. The air traffic controller does not challenge the crew's incorrect readback. Instead of using the modern “glass” cockpit to their advantage, the crew enters the first reporting point into the flight management computer, rather than using the published and required standard departure procedure.
After takeoff and at 750 feet, the Boeing 767 crew turns and proceeds directly to their first reporting point, which is 150 miles from the departure airport. They retract the gear and flaps without incident and accelerate the aircraft to 250 knots. Less than two minutes into the flight, the Mark V GPWS warnings begin: “Terrain! Terrain! Pull Up! Pull Up! Terrain! Terrain!”
The First Officer responds with a gentle pull up from 9.3 to 12.5 degrees. After gaining 200 feet, he lowers the nose to 11.2 degrees, just before the airplane's left wing clips the last 20 feet of a 300-foot uncharted tower – on top of a 3,000 foot mountain! After the incident, the crew raises the nose to 16.9 degrees and applies full thrust.
The airplane returns to the departure airport, and lands with a six-foot long, two-foot deep hole in the left wing leading edge, a ruptured fuel tank, damage to the flap drive, stringers and front spar – and a scar of the tower's red paint across the top of the wing (Figure7).
Unquote.
I know that at first sight, this accident has nothing to do with AF447, right?
Well, let us look at the similarities, or rather, let us look at the arguments used in the AF447 / A-330 case and see how they apply to this situation.
The AF447 captain was crazy to leave the flight deck, prior to the cossing of that terrible zone of terror, the Inter Tropical Conversion Zone.
The B-767 captain was in his seat, as Pilot Not Flying, still the accident happened. Moreover, the captain entered the direct to Henry (waypoint) himself, or he agreed with the copilot doing it.
The A-330 suddenly, unexpectedly dropped itself into the hands of the poor crew, that was never trained to hand fly at cruise altitude. The Alternate Law is way to difficult to handle, etcetera.
The B-767 was hand flown from take-off, all through the standard clean up schedule. No confusing flight laws, how much more plain vanilla than a B-767 can you get? The accident happend at 3,000 feet, in thick, reliable air with lots of engine and aerodynamic performance available.
The A-330 crew was overwhelmed by all sorts of cautions and warnings, with confusing and unreliable faiure indications. The Airbus is geared very much to providing information via the visual channel and the most important warning was an audio warning (STALL STALL).
In the B-767 all systems worked without any glitch, there was absolute serenity in the cockpit, from a systems point of view. The only warning, “Terrain! Terrain! Pull Up! Pull Up! Terrain! Terrain!” was unequivocally loud and clear, and the aircraft, a B-767 does not suffer from the emphasis on overloading the visual channel, to the detriment of the audio input channel into the pilot's brain.
In the A-330 the PNF was not able to monitor what the PF was doing, due to the sidesticks not being interconnected in a physical way, and being obstructed from view. The fact that the state of the aircraft was clearly shown in the form of it's attitude on the perfectly indicating Primary Flight Displays is no reason to exonerate the stupid sidestick configuration.
The B-767 has big, conventional, interconnected yokes, in full view and with lots of tactile feedback to both pilots. The thrust levers ditto, whether actuated by autothrottle servo or by pilot's hand. Still, the PNF did not challenge the PF's lack of reaction to the GPWS warning, one of the most critical warnings in civil aviation. The only signal that got this crew into proper action was the sound of impact with the television antenna.
The AF447 copilots were products of the Nintendo generation, not trained to properly fly aircraft. Culture and training at Air France must be of a terrible standard.
The B-767 event happened in 1992, to a properly trained crew of a reputable German carrier. The Nintendo generation at that time was still, well, playing Nintendo, Super Mario Brothers was just available in stores.
The AF447 crew was caught off guard, surprised by the sudden degradation of their aircraft.
The B-767 crew had plain old fashioned paper Jeppesen charts depicting a Minimum Sector Altitude of 4,300 feet to the north of the airport and clear elevation contour lines and high spots indicating 3,000 feet elevations 5 miles to the northeast of the airport. The mountain El Copey cannot be overlooked from wherever you are at Isla Margarita. Granted, the crew may have arrived in darkness, the night before, and may have spent their entire day in bed, to be properly rested for the accident flight, so, truely, they may never have seen the mountain, but Jepp charts should be enough for proper piloting. How much more prepared could they have been for a GPWS warning? Still, they turned towards the mountain and reacted, well, did not react, to the PULL UP warning.
The almost katatonic reaction of the B-767 crew is a HUMAN FACTORS affair, just like the almost panicky, completely lost, reaction of the AF447 crew is a HUMAN FACTORS affair.
If only the French and the German coplitots had swapped their reactions, both accidents would not have happened!.
Boeing, in the same article has more interesting observations:
Quote:
Failure to Monitor or Manage the Autoflight System.
The advancement of technology in today's modern airplanes has brought us flight directors, autopilots, autothrottles, and flight management systems. All of these devices have been designed to reduce workload and keep track of altitude, heading, airspeed, and approach flight path with pinpoint accuracy. These devices have all made a significant contribution to flight safety.
However, it is possible for them to lead to unquestioned trust by flight crews. The flight crews may unknowingly misuse these devices, or operate them with faulty data. Since autoflight systems are machines, they will do anything asked of them; occasionally, these systems do exactly what they are inadvertantly asked to do – and fly perfectly good airplanes into the ground.
Unquote
Now, back to discussions about autotrim etcetera.