Originally posted by
tk54
I read somewhere that the initial two stall warnings were a valid response to the invalid 60kt pitot reading.
Maybe the stall warning comes first in the relevant part of the computer program , before the validation of the data upon which the stall warning is based?
Originally posted by
Lonewolf_50
Stall warnings, and stall α, are shown in HazelNuts39's graph
They are based on AoA, the magnitude of which is influenced by airspeed/mach number.
I don't understand how you reach the idea of a stall warning based on an invalid (or even a valid) airspeed reading, since stall warnings are (should be?) based upon AoA which is not the same as airspeed. It is a different parameter, influenced by airspeed, attitude, gross weight, angle of bank, G, air density ... etc
From earlier posts: what the 60 knots threshold seems to have triggered is a disabling of a stall warning, which is itself enabled by an AoA reading as shown in HazelNuts39's graph.
From the report:
Note: When the measured speeds are below 60 kt, the measured angle of attack values are considered invalid and are not taken into account by the systems. When they are below 30 kt, the speed values themselves are considered invalid.
The question is has the system rejected a/s (60 kt) by this point? If so, why is it still being honored by AoA logic?
"When they are below 30 kt, the speed values themselves are considered invalid."
Considered invalid by which sub-system? AoA logic? BEA doesn't say.