Originally Posted by
bearfoil
A pilot would seldom need an AH, or BUSS, or AoA 'alert' (other than Stall); except there are those 13 uA/S incidents in which they would have been welcomed, surprise or not.
BEA 2nd report lists almost 40 uA/S (due to pitot) incidents on 330/340. All (apart from 447) involved loss of automatics and reversion to alternate law... and not crashing.
Across this thread there have been pilots stating that uA/S / pitot failure is a "non-event", even on this type. Equally importantly, there are a few pilots who have found it not to be - they aren't here to post. This isn't a type (or manufacturer) specifc issue - a number of the latter group were flying boeings.
One is satisfied with a one hundred year old instrument sensor, (and why not be),
Acutally I am not (satisfied). It looks like a weak point in current aircraft design and deserves further investigation to see if we can improve on something we've taken for granted for so long. Sticking multiple "redundant" probes (of the same type) out into the same environment provides no redundancy to environmental issues such as icing. The B2 allegedly has 20+ sensors...
All that said, a common factor in the pitot incidents that have gone bad is night-over-water - so maybe the right thing to be focussing on is jet upset and spatial disorientation in general, rather than just one instrument that can lead to it.
This type appears to have granted its auto pilot a rather long leash,
Again, this isn't type specific. In other recent incidents the automatics (and this includes the auto-trim discussion) have flown planes to the stall and the parts spread across the landscape have been B, not A.
There is a good general discussion to be had (fragmented across a few threads at present - and maybe deserves its own) on this issue. I do have a feeling that as the industry has given airlines and pilots better and better automatics the, unintended, consequence is that pilots are being barred, by airlines, from flying the plane (SOPs and "safety"). I don't think it can possibly enhance safety if the only time the pilot is handed the controls is when the aircraft is heading
out of control -
on any type.
a host of surprise degradations to handling when its auto flight quits, and a reversion to 'Direct Law', as though that's the ticket to save one's bacon.
A look through the other uA/S incidents shows AP/AThr disconnect and reversion to alternate law. This isn't (or shouldn't be) a "surprise" degradation, or a difficult one to handle, as is evidenced by all the previous
incidents (in fact the only thing that "degrades" are the flight control protections which some airbus critics seem to think shouldn't be there anyway).
Reversion to direct law is clearly not a direct consequence of uA/S (see the other incidents). Something else happened (uA/S may have
started the incident). Someone (I think it was the pilot union head quoted in Spiegel article) has stated that the
pilots initiated the PRIM reset - although how they know this isn't made clear. Obviously it didn't save their bacon whether it was pilot or system initiated - but my hunch is that they were already irrecoverable at that point.