Why does the A350-900 call out to retard at 20 feet above the runway? I watched this video of a delivery of an A350.


                
            

at 14:50 there is the sequence I'm interested in: the ground radar normally counts down the distance to the ground, but shortly after the 20 feet mark, it calls the typical "retard" to pull the levers back.

Why is it like this and not like normally at 0 feet?
Why is it like this and not like normally at 0 feet?


Normally is not 0 feet: all Airbus (maybe with the exception of the A380, that might have a longer flare) have a "Retard" call at 20ft, not at 0ft. From the A320 Flight Crew Training Manual:


  As a reminder, the ”RETARD” aural alert will sound. In flare, this aural alert will occur at 20 ft, except in the case of autoland, where it occurs at 10 ft.