Originally Posted by
roundsounds
Interestingly the Cirrus SR 22 has a feature whereby if there is no crew input to certain systems after a set period, the autopilot commences a descent to 10,000'
This might cause some trouble over certain mountain ranges ...
Vertical Speed:
1. AP executes 90degree left turn and pitch down.
2. Speed controlled near Mmo/Vmo and level off at 15,000'
3. EMER DESCENT annunciated on PFD
Fewer mountain ranges cause trouble with this.
I disagree with kwh that such over-automation is needed. Additional complexity for what value that cannot otherwise be mitigated? Further this point, the recent concerns over Normal Law Alpha Protect taking control from pilots (due to a malfunction) reminds us that with every feature like this you put in, you induce the potential for yet another novel failure mode.
Fix one perceived problem and raise another that you won't discover ... until it happens, perhaps in flight.
Further a point ia raised a bit earlier:
Task saturation/task focus.
Whatever went wrong at altitude, there is the potential, as with AF 447 and the recent Indonesian accident, that the two pilots were consumed with the first two prime directives of flying -- aviate navigate -- (and part of aviate being get plane in control and fix / trouble shoot what's wrong with it) that their task loading did not get to the communicate/squawk change step. While in those two cases upset looks to have been the core problem, and in this case not, that doesn't mean that a serious malfunction didn't occur that wholly occupied the attention of the flight deck crew.
If you go back about ten pages and re read the strange case of the leaking fluid that sickened the captain and the FO in the terminal environment ... a rare but nasty malfunction.