Autothrust behaviour with corrupted airspeeds
Hi there
I am in search of the basic principles of the autothrust and its different modes/settings.
If you are in high altitude cruise, approaching a tropical storm cell with possible turbulences (but not using the "severe turbulences" procedure putting the A/THR off and fixing N1), what would be the selected mode ? Speed mode ?
In speed mode, with airspeeds fluctuating down to a largely understimated value (caused by a ram air port freezing of the Pitots for instance), would it be possible that the A/THR augment the thrust just before disengagement ? (what would be the time constant of the thrust control loop ?). If yes, is it possible for the crew not to notice this thrust level increase ? even in max thrust ?
Are there known exemples of unusual behaviours of the autothrust systems both on Airbuses or Boeings ?
Jeff