I have reinstalled FS9, including FSNavigator and use FSNAV to control most of my autopilot functions. Either it or all of my aircraft autopilots are completely failing at some point during the flight, causing me to lose all control of the aircraft. The airspeed indicator goes to zero, I go into a "Dive of Death" but the plane seems to recover somewhere around 6000 feet or so.Can anyone tell me if they've seen this behavior and how I can fix it? I seem to remember having this problem before but I can't remember how it was fixed. I also have FSPassengers installed but all failures are disabled at this time.

Hi sounds like it may be to do with the pitot heat. Try turning it on before flight by pressing Shift H.

Thanks, Jason. I thought about that and I THINK I had the pitot heat on. But I'll be more conscious of it.

This problem has cropped up again only this time about 400 miles into a flight from EGLL to KBOS, and with a little twist to it. I was using the preloaded "Fair Weather" scenario and as I'm quietly climbing through about FL280 using FSNavs Fly Flight Plan feature that runs with my Overland 777LRs autopilot, instead of all my speed indicator instantly falling to 000 kts and the thottle pegging out to max, this time both of my altitude meters and airspeed indicators jump to over 60,000 feet and 490 mph respectively, and I get a "Cockpit Tip" telling me my barometer isn't set correctly for high altitude flight, when I had manually set it to 29.92 through FSPassengers L key feature. I then tried to set it manually on the panel with the mouse with no effect -- all sypmtoms persist. As soon as I get down to about 15,000 feet, all instruments return to normal, correct readings and I can restart my climb.My pitot heat was on from engine start, and I was watching my instruments carefully all through my climb, so I'm pretty sure I'm not REALLY at FL600 and 470 kts (but who knows?).Can anybody help? This is driving me mad! This is a fairly new and clean install of FS9 and FSNav on a new build -- less than a week old -- and it happened again! Could this be attributable to some sort of hardware issue -- heat, perhaps?As always, thanks in advance for taking the time to read this, and any suggestions you may have.