"John Alger" wrote in message
m...
"John R Weiss" wrote in message
news:S08%b.58709$4o.76896@attbi_s52...
"Tarver Engineering" wrote...

Since my servers seldom get me all the newsgroup messages and
Google.groups can't seem to find the begining of this thread, please
allow me to ask a question and pose some answers. And I apologize if
any of this has been discussed previously.

From the bits I have read subsequent to John's message above, I assume
we are discussing the A-320 crash at Habshiem. If so, let me present
some information relevant to the discussion, as I have not read
anything as yet that indicates any of the posters knows much if
anything about Airbus flight control systems.

I do believe I am qualified to speak on the subject as I teach A-330
systems, which has a flight control system identical to the A-320.

The A-320 which crashed into the trees in France was performing a
fly-by demonstration, by a line pilot, not an Airbus test or demo
pilot. The profile was to fly by at 500 feet.

The pilot was making a scheduled revenue flight with passengers and came up
with the low slow fly by all on his own.

The aircraft was below
100 feet. This is significant to the incident (and not just because
that is where we find trees). In the Airbus the computers have a group
of flight control protections collectively known as "Laws". In Normal
Law there is a low-speed, high AOA protection known as Alpha-Floor.
Alpha-Floor is reached somewhere below Vls (the lowest speed the
aircraft will fly with autopilot/autothrust on and sidestick in
neutral), and prior to Alpha-Max (maximum AOA). At Alpha-Floor the
autothrust commands TOGA power, and regardless of how much you pull
back on the sidestick, the aircraft will not decelerate below
Alpha-Max. It will just mush along at TOGA power until it runs out of
gas or the pilot lowers the nose to accelerate.

The low fly by was not an A-320 flight mode.

The problem is, Alpha-Floor is not available between 100' and
touchdown - otherwise you could never land! The pilot was expecting
Alpha-Floor, but being too low, it did not happen. By the time he
realized his error, he applied power, but it was too late. You can, in
fact, hear the engines spooling up just prior to his impact with the
trees in the video we show in class.

That is what I have been attempting to communicate to Weiss.

The aircraft performed as it should have. The pilot simply did not
have an adequate understanding of his aircraft for the manuver he was
doing. He also failed to follow the script. Two things the French
apparently frown upon, expecially when used in combination.

Yes.

It is not just the French that believe the POH is part of the Type
Certificate for an airplane.

Lesson: if you don't fully understand your aircraft, it can reach out
and bite you someday.

Weiss is in danger every time he flys then.