PPRuNe Forums - View Single Post - AF 447 Thread No. 12
View Single Post
Old 13th Sep 2014, 06:47
  #364 (permalink)  
Owain Glyndwr
 
Join Date: Jun 2011
Location: West of Offa's dyke
Age: 88
Posts: 476
Likes: 0
Received 0 Likes on 0 Posts
Machinbird


Some have discussed keeping hands off completely in the period immediately after the A/P disconnected and the switch to Alt 2b law.

Just a personal opinion, but that course would have a high probability of ending in a spiral dive. There is nothing to level the wings in Alt 2b but the aircraft's natural roll stability (which isn't all that good in most jets).



We don't have to speculate - Fig 64 of the Final Report shows a simulation of the aircraft response to the turbulence present both with and without pilot input.


With no pilot inputs 40 secs after loss of airspeed the aircraft would have ended up at 280 kts CAS, FL350, 3 deg pitch, a shallow climb and bank wandering around 10 deg right, but not divergent.


Just a thought, but there is nothing to say that Alt2b loses the stability augmentation terms (roll and yaw damping) in the laws.
Owain Glyndwr is offline