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Old June 2nd 11, 03:46 PM posted to rec.aviation.piloting
Dylan Smith[_2_]
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Posts: 53
Default Air France Black Box ResultsPilot Error

On 2011-05-29, James Robinson wrote:
No, the system switched to alternate law all by itself when the speed
signals went screwy, and there was no need to shut off the automation.


Indeed.

On the surface, the pilot lost control of a perfectly flyable airplane,
which was in stable flight before he took control. However, part of the
investigation certainly has to be why the pilot flying didn't put the
nose down as a reaction to repeated stall warnings. This is something
any pilot learns when first starting to fly, and should be a natural
reaction when hearing the alarm. Was he overwhelmed by all the alarms and
missed the stall warning? Did he think he was correcting for wind shear
or some other problem?


Like any crash, there is a chain of events. There could be user interface
issues (a famous example of this was the Three Mile Island incident,
a famous aviation related incident of bad user interface being a
contributory cause of a crash was the Boeing 737 that crashed near
Kegworth in England after the crew shut down the wrong engine).
There could be training issues. I'm certainly not going to condemn
a crew even though on the obvious face of it, it may look like pilot
error. There is likely to be plenty of contributory factors.

The pilot of the Colgan Air flight approaching Buffalo did the same
thing, and some studies suggest that when surprised, the majority of
pilots will try to pull the nose up when they hear a stall warning, which
is exactly the wrong thing to do.


I think in the case of Colgan Air, the recent emphasis on icing related
tailplane stalls (recovery procedure the opposite of main wing stall)
may have been a contributory cause. Similarly, perhaps the high emphasis
on windshear recovery (which when all the automation in a modern airliner
be it Boeing or Airbus is to do a maximum performance climb, which may
not work as expected if the automation is turned off and the crew are
too busy to remember that stall protection has gone away). These
aren't the first times either, long before automation was a factor
a crew crashed a Hawker Siddeley Trident 3 (an airliner superficially
similar to a Boeing 727, 3 engines and T-tail) near London by getting it into
a deep stall. After inadvertently retracting the leading edge devices,
the crew deliberately deactivated the stick shaker and pusher while
pulling up, getting the aircraft into a deep stall from which it was
impossible to recover. Why? There had been recent incidents of false
stick shaker activations, the weather was not great, the captain had
an undiagnosed heart condition which may have started to cause him some
pain thus fogging his judgement, there were industrial relations problems
(with the captain on one side of the argument and the rest of the crew
on the other), and the first officer was timid about challenging the
captain's decision to keep pulling back on the stick because he had
recently been reprimanded for challenging a captain. So the captain
assumed it was a false activation of the stick shaker and turned off
the stick shaker and stick pusher, and stalled it.

Is it just human nature to pull back
on the controls, thinking you want to stay away from the ground, rather
than point the aircraft at the ground to recover?


And how often is stall avoidance/recovery trained for in an airline
setting?