17:44

Human Error

One of the more goulish things about being a pilot is that you get sent regular update on crashes - the idea being that it is less painful to learn from other peoples' mistakes than your own. What is amazing is how many experienced pilots make a perfect landing with their wheels up or take off with the dolly that is used to manouver the aircraft on the ground attached to the front wheel. Believe me, anyone can do it. I'm not a naturally methodical or careful person - except with flying. There is a check-list for everything or I know I'll kill myself.

With this in mind it was particularly shocking to read the recent account of the Air France Airbus crash that occured in mid-Atlantic in 2010 during a flight from Rio to Paris. It was a  mystery for a some time until they found the Black Box flight recorder - how, at the bottom of two miles of Atlantic, I don't know. What it revealed was that the pilot had stalled a perfectly sound, state of the art,  aeroplane from 37,000 feet into the sea. No mechanical, computer or airframe failures - only human.

The Airbus was in mid-flight when the Captain handed over to the experienced First Officer, who remained in the right seat, and the inexperienced  Second Officer who climbed into the left seat - traditionally the pilot's seat. The captain went next door to sleep. They were near the equator, an area of frequent thunderstorms, and they could see storm clouds ahead. The decision was made to climb through the top of
it. The fuel-heavy Airbus was not capable of flying over it.

The Airbus is a 'fly-by-wire' aeroplane with two 'sticks' beside each seat.In less sophisticated aircraft there is a mechanical linkage between the two sticks so that if one pilot pulls one stick back the other will feel an identical movement in the other. The airbus's arrangement is analogous to two computer mice where an input on one leaves the other stationary.

The (inexperienced) Second Officer, who had control,commenced a climb. As he did so, the pitot tube which allows air into the airspeed indicator iced up and  the airspeed was allowed to decay up to the point that the Airbus stalled - there was not enough airflow over the wings to create lift and the plane was falling, nose up, at a considerable rate. To get out of a stall, you  push the stick forward and wait until the airspeed has built up again before pulling back to straight and level flight. As the altimeter unwound the First Officer was looking wildly around for what was wrong. What he didnt know was that the Second Officer, for some unknown reason,had the stick held fully back - probably he had 'frozen'. The First Officer could not feel anything because his stick was standing in a neutral position. There were moments where control was regained but the pattern continued to repeat itself.

In a cockpit there is normally a clear pyramid of authority with theCaptain at the apex. When a Quantas flight recently had a multipleelectronics failure the Captain straightaway parcelled out tasks to the flight-deck crew to isolate the critical malfunction resulting in a close-run thing but no catastrophe. On this Air France flight, with only two secondary flight crew in the cockpit, there was crucial lack ofauthority, exacerbated by the inexperienced Second Officer sitting in the left seat. This arrangement was almost certainly critical when the Captain,just awakened and very alarmed, appeared on the flight deck. He sat  behind in the Second Officer's seat, and did not take back the pilot's seat next to the left stick. He, also, had no idea that that stick was being held fully back.Too late, only 10,000 ft above the sea,the First Officer realized whatwas happening and applied forward pressure to the stick which was cancelled out by the back pressure from the other seat and, still in a stall,the Airbus hit the ocean.

When you read the monthly litany of accidents it nearly always pilot error,of some sort or another, that is to blame. It is often to do with weather - get-home-itis as is nicknamed - or not noticing something wrong when a methodical check would have nailed it. This Air France flight must be right at the top of the tree when it comes to 'human factors'.
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