Tarver Engineering
February 27th 04, 07:06 PM
"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 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 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.
>
> 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.
>
> Lesson: if you don't fully understand your aircraft, it can reach out
> and bite you someday.
>
> John Alger
> A-330 Flight Crew Training Instructor
> Former rides: TA-4J, A-7E, EC-130Q and P-3B
Eat ****, Johnny.
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 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 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.
>
> 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.
>
> Lesson: if you don't fully understand your aircraft, it can reach out
> and bite you someday.
>
> John Alger
> A-330 Flight Crew Training Instructor
> Former rides: TA-4J, A-7E, EC-130Q and P-3B
Eat ****, Johnny.