PPRuNe Forums - View Single Post - AF 447 Thread No. 7
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Old 24th Nov 2011, 18:47
  #488 (permalink)  
Machinbird
 
Join Date: Jul 2009
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Grity,
The two videos are a bit of apples and oranges comparison with the AF447 initial PF control motions. Let me try to explain why:

First, the aircraft are landing, so the followng applies:
FLARE MODE
The flight mode changes to flare mode at landing, when passing 100 feet.
Flare mode is a direct stick-to-elevator relationship (with some damping provided by load
factor and pitch rate feedbacks). In addition, at 50 feet, a slight pitch down elevator order
is applied, so that the pilot has to move the stick rearwards to maintain a constant path,
so as to reproduce conventional aircraft aerodynamic characteristics.

Second, since the aircraft are landing, the aircraft must be in the proper location and attitude for "ground interface". This requires increasing attentiveness on the part of PF. It is a bit of a "crescendo" effect.




Third, There is a major difference in the control techniques displayed compared with the AF447 PF technique.
  • In the videos, the majority of the control inputs are pulses from neutral (Until Flare mode is activated).
  • On AF447, the control inputs were continuous.
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