Originally Posted by
jcjeant
It would be surprising Airbus have not taken into account a safety margin
For me I read through this to mean:
Alpha max is the highest alpha that the flight control computers will allow for a given configuration and weight; it provides the max lift coefficient (with a safety margin)
You might be right, but to my reading the difference between the alpha protection threshold and alpha max *is* the safety margin. In fact it's the primary safety margin. There is a secondary safety margin between alpha prot and alpha max, which is the alpha
floor trigger value.
None of this is relevant to AF447 though, because protections were out of scope.
DW
I suppose you mean First instead Last
You have First is Last in a single command when pulleys and cables are used for transmit the inputs
I wasn't talking about that sense, I listed three primary inputs to the autotrim system, of which the third (and last) was the flight control commands which are human under hand flight:
Code:
IN PROCESS OUT
Elv.Position|------------|
----------->|Autotrim |Trim Cmd
THS Position| |------>
----------->| |(to THS &
Pr.Flt.Ctl | System | trim wheels)
----------->|------------|
(Yes it's a gross oversimplification, but I hope it makes what I was trying to say clearer... - EDIT : Apologies for it being a little wonky - the code tag seems to behave differently between preview and posting for real...)
A Primary Flight Control input which is neutral is still an input to the autotrim system - it cannot make flightpath decisions in isolation (unlike autoflight).