O2 single pilot and VLJ

Some small jets are currently certified for single pilot operation.

Is the only pilot required to don his mask above some altitude?

Do they actually do it?

Does single pilot operation require a smart "descend if pressure is low" autopilot?

I read a recent review of the new gulfstream that the autopilot automagically descends if presure is lost.



As a side note I read in todays USA today a description of a 727 incident in 1996 where
pressure was lost and both the pilot and flight engineer passed out.
The co-pilot with 10 hours time in type saved the day.

I sense a new rule comming.....


Paul