PPRuNe Forums - View Single Post - AF 447 Thread No. 6
View Single Post
Old 19th Aug 2011, 17:33
  #181 (permalink)  
rudderrudderrat
 
Join Date: Oct 2009
Location: UK
Posts: 1,270
Likes: 0
Received 0 Likes on 0 Posts
Hi Clandestino,

Don't you adapt your inputs to achieve desired attitude, no matter what control law are you in?
Yes you do. But suppose you are "overloaded" by warnings as you struggled to maintain wings level. Consider these two alternatives.
1) In Direct Law, the stab trim would not have moved. If PF relaxed the back pressure, the aircraft would have nosed down naturally whilst it attempted to regain it's trimmed speed.
2) In ALT LAW, when he relaxed back pressure, the aircraft maintained it's nose up attitude as the speed washed off.

In which Law do you think is easier to actually stall?

@AlphaZuluRomeo,
The thing is AoA probes (needed for stall warning & FPV) are (or deemed) unreliable when IAS<60 kts. I'm not sure an unreliable FPV and/or stall warning is better than none at all?
The IAS was grossly under reading. The acute angle of attack to the pitot tubes rendered them useless. The fact that the aircraft is airborne should be sufficient logic to maintain stall warnings and Angle of Attack.
rudderrudderrat is offline