This incident was a puzzler and the result was the worst aviation crash in British history. A BEA Trident takes off from England for Brussels. A few minutes into the flight, still at a low altitude, the airplane stalls and flops onto the ground, killing the crew and all the passengers.
The investigatory agency set about its business of trying to uncover the cause. (These guys are amazing.) One by one, they eliminate potential contributing causes: weather, engine failure, instrument failure, and come up with nothing.
In the end, their best guess is a combination of things. There were four pilots on the flight deck. The pilot was twenty years senior to the others. A strike was looming and the captain, a stalwart who operated by the book, opposed the strike and had loudly chewed out other employees before take off, no doubt intimidating the other members of his crew and very likely triggering an unexpected cardiac event in the cockpit. As the pain increased, the captain's discomfort grew and distracted him from the task at hand.
So far, so bad. In addition, the investigators found that the "droops" had been retracted far too early. The droops are extensions on the leading edge of the wing that increase lift when deployed, as in take offs. The retraction of the droops caused a sufficient loss of lift to put the airplane into a stall.
Why had the droops been retracted? The best guess is that someone in the cockpit thought he was retracting the flaps, not the droops, because though the two handles were not side by side, the design of their handles as identical, so it was an easy mistake. In fact, other pilots flying the Trident had reported the same problem.
Yet, like most modern passenger liners, the Trident had a marked stall warning called a stick shaker. As stalling speed approached, the controls vibrated vigorously and unmistakably. The pilot had shut them down and overridden the stall warning and so evidently he didn't realize he was in a stall.
There was, therefore, no single cause of the crash, but rather a tragic juxtaposition of independent events, a cascade from the argument at the airport to the destruction of the airplane in a farmer's field. The usual corrective measures were taken but the Trident went out of operation a few years later, anyway, replaced by Boeing's 707.
The investigatory agency set about its business of trying to uncover the cause. (These guys are amazing.) One by one, they eliminate potential contributing causes: weather, engine failure, instrument failure, and come up with nothing.
In the end, their best guess is a combination of things. There were four pilots on the flight deck. The pilot was twenty years senior to the others. A strike was looming and the captain, a stalwart who operated by the book, opposed the strike and had loudly chewed out other employees before take off, no doubt intimidating the other members of his crew and very likely triggering an unexpected cardiac event in the cockpit. As the pain increased, the captain's discomfort grew and distracted him from the task at hand.
So far, so bad. In addition, the investigators found that the "droops" had been retracted far too early. The droops are extensions on the leading edge of the wing that increase lift when deployed, as in take offs. The retraction of the droops caused a sufficient loss of lift to put the airplane into a stall.
Why had the droops been retracted? The best guess is that someone in the cockpit thought he was retracting the flaps, not the droops, because though the two handles were not side by side, the design of their handles as identical, so it was an easy mistake. In fact, other pilots flying the Trident had reported the same problem.
Yet, like most modern passenger liners, the Trident had a marked stall warning called a stick shaker. As stalling speed approached, the controls vibrated vigorously and unmistakably. The pilot had shut them down and overridden the stall warning and so evidently he didn't realize he was in a stall.
There was, therefore, no single cause of the crash, but rather a tragic juxtaposition of independent events, a cascade from the argument at the airport to the destruction of the airplane in a farmer's field. The usual corrective measures were taken but the Trident went out of operation a few years later, anyway, replaced by Boeing's 707.
