Originally Posted by MurphyWasRight
On the other hand there is a huge difference between inhibiting initiating a stall warning at <60Kts and arbitrarily -stopping- an existing stall warning when the (sensed) speed goes from 60 to 59 Kts and then even worse-resuming- the alarm just as corrective action is taken (nose down) and the sensed speed rises above 59Kts.
(mumble-mumble) Nigel remarked
The airframe / software designers have to work to some parameters. Knocking off AoA interpretation below 60K IAS seems valid enough to me - and also at that sort of airspeed you are not just "stalled" in the normal sense of the word - you are a falling leaf.
With that in mind Murphy, I am willing to have the stall warning go away at 60kts if you are say 1000' above ground level and not replace it with something else. Above 1000' AGL I'd expect the stall warning to change as airspeed drops below 60 knots, perhaps to a shrill woman screaming, "You're gonna die!" or something else equally attention getting.
It is still a stall in that the surfaces are producing no meaningful lift. It's one that probably requires breaking the aircraft's symmetry - full thrust RHS and idle LHS might convert it into something that could then be converted into a airspeed restoring dive. It'd be risky. It'd be better than dying. (And the farking trim should be zeroed on the basis of Otto telling pilot, "Let's try this one again, Fred." Give the poor plane a CHANCE of recovery, please!)
AF447 was placed 3950 meters under water by an amazing cascade of cockpit errors (mostly due to training), conditions that designers never thought possible, friendly controls that suddenly turned well meaningly hostile, and incredibly bad instruments only conditions that made visual recovery impossible.
It might be instructive for somebody more aware than I to go through the report as we have it now and delineate items that if changed the plane would have landed somewhere safely. Start at, perhaps, 01:35 during the flight.
For example had communications existed the pilots might have requested a wider deviation. (But then, maybe not. They never were heard squawking on VHF.)
Or had a radar existed that could spot the fuzzy frozen water ahead of the plane they'd have use that radio then deviated around that nasty stuff.
Had stall warning (really, impending stall warning) training not stressed potentially spurious warnings and recommended recovery as apply power and nose up (I still don't grok that) they'd have stayed level and made it the rest of the way through that murk with a modest anecdote for their troubles.
And so forth. Locate places the scenario could have been broken. Then let's start looking at them for improvements we can suggest. That's pretty close to what the BEA would be doing. They have better data. We have more heads. Advantage - who? Hoped for result - another digit following the "99.x%" reliability figures.
I don't have a relative or friend who died in this. (That was an other event.) So I've no real use for "fault" or "blame" as in "somebody to....". Let's make flying safer for both pilots and packages of Self Loading Ambulatory Meat.
A systematic search might be more productive than the one person shot in the dark like Av Leak produced. (Heh, I used to work for a sister publication at one time as a moonlighting adventure. Press passes to COMDEX were FUN.)