My MADDOG stalls at high altitude Options

[jfri]

During my two latest flights with the Maddog this has happened. At high altitude (30000 ft or higher) the sound alarm STALL goes on. I notice that the speed is rather low. This happens when the autopilot and autothrottle is engaged.
I would expect the AP to give sufficient power for the climb which has been the case earlier during the climb. What could I have missed? What vertical speed should be possible at these altitudes?

[comanche]

During my two latest flights with the Maddog this has happened. At high altitude (30000 ft or higher) the sound alarm STALL goes on. I notice that the speed is rather low. This happens when the autopilot and autothrottle is engaged.
I would expect the AP to give sufficient power for the climb which has been the case earlier during the climb. What could I have missed? What vertical speed should be possible at these altitudes?

This happens because several causes:
1. Sufficient speed (at least 290 Knt should be reached as soon as possible over 10000 feet (using IAS instead V/S)
2 V/s should be gradually reduced (no more than 1000 ft/m over 30000 feet)
3 above 26000 feet speed should be changed to Mach and progressively increased (from .64 to .76 at high altitude). IAS sharply reduces at high altitudes and is IAS that sustains the aircraft.

Mauro