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Speed indicator going from 280kts to 000 kts inflight..

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I was doing a flight from RKSI to KSFO and had the autopilot hold at 0.84Mach and FL330 using the default 744 panel and MelJet's Version III Korean Air repaint.An hour out of Incheon Airport, the airspeed indicator suddenly goes from about 280kts IAS to 000kts IAS, and the autothrottle automatically revs up to full power, but the speed remains 000kts on the indicator. At this time, my ground speed increases to over 600kts with favorable winds, and my mach indicator is well over 0.90mach, with no overspeed indicator.What happened?

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>Check to make sure your pitot heat is on. Tom Where do I check? I don't see anything on the panel.

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If the panel lacks a Pitot Heat switch, you can turn it on by pressing SHIFT+H. It's best if you simply turn it on at the beginning of your flight and leave it on.

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Hi,I sem to have the same problem ""at times", it seems this problem onlt came up after I installed "Active Sky"...not that there is anything wrong with this program, I use it all the time..sometime it acts up...sometimes it does not? I seemed to notice the prob occur when a new altimeter reading was loaded??? Any suggestions Damien? Excellent program!ThanksMb

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>I was doing a flight from RKSI to KSFO and had the autopilot >hold at 0.84Mach and FL330 using the default 744 panel and >MelJet's Version III Korean Air repaint. >>An hour out of Incheon Airport, the airspeed indicator >suddenly goes from about 280kts IAS to 000kts IAS, and the >autothrottle automatically revs up to full power, but the >speed remains 000kts on the indicator. At this time, my >ground speed increases to over 600kts with favorable winds, >and my mach indicator is well over 0.90mach, with no >overspeed indicator. >>What happened? Surely the problem was with heat pitot off. Turn it on and you

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Hi all, I don't think it has to do with the Pitot or the Anti-ice functions, that have no effect on the flight dinamics or on the systems, at least in the default AC.I have noticed this also, and it has to do with some kind of bug from Activesky, I think it has to do with some downloaded winds aloft, for some given altitudes.That happen to me several times and it was corrected changing my cruise altitude, often to a lower level. HOpefully, the next version of Activesky will include a fix for this issue.I don't have Damian's e-mail, somebody can please report this little bug?Thanks.

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I don't use ActiveSky but my airspeed indicator freezes sometimes too, however I cannot confirm if switching on the pitot heat solves the problem, I just see most people saying that's the solution...Kitty MercuryCathay Pacific Virtual Pilot (CX252)

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Sure enough, it seems like a pitot heat problem. I do wonder, however, why this doesn't happen every time I fly? Thanks everyone!

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Because, you don't have icing conditions everytime you fly.

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There was a discussion about extreme low OAT when usig activesky. It's not because of winds. Airspeed indicator 'jams' because of too long OAT without any heating.

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Gabriel,Indeed, unless there is another problem at work, it is related to not having the pitot heat on.First, Microsoft has improperly modeled the problem, second, in real flight it doesn't always happen, and third, it can be avoided (and fixed when it occurs) by turning on the pitot heat (in FS2002). In real life, if the pitot heat is not on and freezing conditions are encountered, it is POSSIBLE that moisture may freeze in the pitot tube and block it, thus making it inop. BUT, when this happens, it is more likely that the airspeed will act like an altimeter, or freeze in it's current position than go to zero.As Microsoft has modeled it, if you fly into/through the clouds above the freezing level, and pitot heat is off, the airspeed will fail to the bottom of the scale EVERY TIME. If it happens, turn on the pitot heat and be patient, a few minutes later the airspeed will return.If autothrottle is engaged at the time, simply turn off the A/T and set the power manually to maintain speed until the airspeed comes back.As previously noted, the problem can be avoided all together by simply turning on pitot heat on pre-departure as is good practice and SOP in jets to start with.A final note: In reality, flying above the freezing layer in cloud with no pitot heat does not guarantee that the pitot system will freeze over and fail. Below -15C at altitude the moisture is typically already frozen, so pitot tube icing would not likely occur, especially at flight level cruise. Flying through freezing rain is another story altogether :-)Best Regards,Tim Sanders, ATP

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