Dear PMDG,Since I have installed the 800/900 service update, it appears that I get the speedtape to zero situation much more often than usual.This has happend to me before, but not so many times! It happens even cruising at 19,000.The result is the autothrottle kicks into max power to try to correct the wrong speed. Hence the true airspeed goes up and well into the MSFS "overspeed" warning.I thought this occurence would only happen if the pitot tubes heating was off and in cold conditions, but id say ive had it happen to me over five times in the last two weeks, and the weather didnt appear to show cold scenarios.. it is summer after all!Maybe through AS2004 im just downloading some seriously cold weather (EGLL realtime), or has the wind bearing on the pitot tubes have an effect too ?Any help would be greatly appreciated!Best regards.Armen L Cholakianwww.veryquiet.comhttp://forums.avsim.net/user_files/86931.jpg

Hi Armen,that's a known issue with AS2004 and PMDG, for what I remember. You can give a look at the AS forum. Many users did experience this, with all the PMDG 737 variants and with the Pitot heaters ON. So far, I think that no reason/fix has been found. To me it happens randomly, lasts about 3 to 10 seconds, doesn't seem to affect normal operations (A/T stays ON and running, A/P doesn't disconnect, no stall/overspeed warnings), then vanishes. If it persists for more than, say, 15 seconds or so, the A/T could go awry: in this case, disconnect to A/T and use manual throttle to maintain speed.Some user reported that switching all the anti-ice protection ON, even with no ice threats, can help. To me, it doesn't.You could try to disable in AS2004 option menu all the icing, some user reported it fixed the speed-to-zero problem.Could be that the new MR of AS2004 will cure this.For the moment, my suggestion when it happens is to sit quiet and wait !Hope this helps.

Or, make sure that the 'Prevent All Icing' option is checked under the AS2004 options. I leave this option unchecked, and have not seen my indicator zero, but I also have FSUIPC allowing icing, just nothing severe. I'm not sure if this is only for a registered version of FSUIPC, but it's there, just so you know.

I have noted this several times now. The speed tape, the altitude, and the rate of climb/descent are frozen using the "Z" panel. I switch to the "A" panel and the readings are correct for the situation. When I switch back to the "Z" everything is correct again as if nothing had happened.RichR

It's a known FS glitch to me. It happened every once and a while when I was flying the default planes.Nick B.Continental Airlines Virtual 737NG Pilothttp://www.precisionmanuals.com/images/forum/800driver.jpg--AMD Athlon XP 3200+ @ 2.2 Ghz (Equal to 2.8 ghz)400W Power supply3x 80 mm Case FansSoyo VIA KT600 Dragon PlusnVidia GeForce FX 5200 128 mb2 x 512 PC400100 GB Western DigitalMicrosoft Sidewinder Precision 2