PPRuNe Forums - View Single Post - AA A321 takes off after smashing ground sign
Old 19th Jun 2022, 04:16
  #138 (permalink)  
FlightDetent

Only half a speed-brake
 
Join Date: Apr 2003
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Age: 46
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Follow up on the steering:

Ground mode is a direct relationship between sidestick deflection and elevator deflection, without auto trim. [FCOM DSC 27-20-10-20 A]

For roll control during take-off, the transition from Ground Mode blends into to Flight Mode (full FWB magic) over 0,5 seconds after the pitch reaches 8 degrees N.U. Thus anything afer 20:40:34 is roll demand control of the FBW - assuming it is what it actually does (pitch normal law is most certainly not a simple 1g command as the FCOM explains).

More observations:
+ despite full and dual R sidesticks, the aileron deflection is not maximized after Flight Mode becomes active. At 20:40:35 this is understandable, as the roll 1st derivation (not charted) peaks with reversal of the bank. Inbetween secon d 34-35 it is bit more confusing. Maybe the effect of absolute symmetrical deflection being reduced due to tkof aileron droop?
+ seconds 39-40 the aileron displacement is not symmetrical
+ we don't know the impact moment. Assuming it happened at recorded max bank is not correct.


Last edited by FlightDetent; 19th Jun 2022 at 04:30.
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