PPRuNe Forums - View Single Post - Flight Directors off for stall practice in the simulator.
Old 19th Jun 2018, 06:59
  #27 (permalink)  
vilas
 
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INDIGO
We also have danger of mode reversion if we don't follow the FDs.
That is interesting. Since we are discussing stall we can only be in alternate law. So no hard protections which cannot be overridden and no auto pilot. ATHR may or not be there.Now let's see mode reversions. I assume you are referring to Speed protection when FD orders are not followed by the flight crew(AP NOT ENGAGED). In these protection there are two dimensions one is when the speed increases to VMAX+4 and the other is when speed decreases to VLS-2 or with speed brakes extended VLS-2 to VLS-19. Speed increase won't bother us because aircraft will not stall. If speed decreases below the value mentioned above then
FD bars disappear. If A/THR active, automatic engagement of SPEED mode on the A/THR. Thrust increases to recover the speed target.
So again no stall so where the danger that you see. Rather it is good. The very purpose of reversion is to prevent speed reduction below unsafe level.
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