Airspeed indicator stopped working.

[BeeKing85]

Today, I made a 2 hour flight from KLAR Laramie Regional, Wyoming to KVEL Vernal Regional, Utah. I was cruising at 12,000 ft when I hit a patch of bad weather mixed with some rain. I noticed my airspeed indicator stopped working so I turned on the pitot heat and watched the airspeed indicator begin functioning again. The rain stopped about 10 minutes later, so I shut to pitot heat off.

Fast forward 40 minutes into my flight. I noticed my airspeed indicator stopped working again, so I did the same thing as before, I turned on my pitot heat. Unfortunately this time around the airspeed indicator did not start to function again. I was puzzled. So I thought maybe it's really really frozen so I left the pitot heat on. 20 minutes go by and the airspeed indicator is still not working. I thought maybe I should pull the alternate static source valve, that might solve the issue. But it did not. I had checked for icing conditions before hand but did not see any along my route. (BTW I am using Active Sky Next Steam Addition for Live Weather)

I ended up having to land without my airspeed indicator, using only my GPS and DME for ground speeds. The landing was smooth enough as I had the luck of good weather, calm (ish) wind, and good visual. I was curious to check out the maintenance hangar after I taxied to GA parking. To my surprise, there was nothing wrong in the hanger. It said "in beautiful shape", nothing in yellow or red. Just all around green. I shut down the plane, and restarted FSX. Loaded up at the same airport and started the plane up again. I did my pre-flight checks as always, and the pitot heat was functioning correctly. Checked to see if the static air port was clogged, which it wasn't. I started taxing around to check to see if the airspeed indicator was working. It was. It seems to be working fine now.

So i'm not sure if this was a one time glitch or what. I didn't do anything other than restart FSX. This has never happened before (though I just recently bought the C172, having about 40 hours on the plane at the moment). I did install the latest Accu-sim 3_30_16 patch last night. Maybe that had something to do with it.

Has anyone else experienced this issue? Before or after the latest patch? Thanks in advance for any help, thoughts, or comments. Happy Flying

[EnDSchultz]

I have had this before and I'm convinced it's some sort of conflict between how Active Sky Next handles icing and Accusim's handling of the pitot-static system. Sometimes the ASI will ice over and pitot heat will simply not clear it. You will notice that your airspeed in the red Shift+Z overlay will drop to zero when the pitot freezes over, and will return to normal once you activate the heat...but the ASI in the cockpit sometimes won't.

As long as your pitot heat is ON, you won't have any problems. Therefore, I make it a policy in my Accusim planes to leave the pitot heat ON at all times, preemptively, if there is any chance I will encounter sub-zero temperatures during the course of my flight. As far as I can tell, Accusim does not simulate the pitot heat burning out in warm ambient temperatures so this is safe to do in the sim and averts the annoying ASI failure bug.

[Welsch]

Has happened to me sporadically throughout the fleet in the past. Only way to clear it once it gets stuck is to reload plane in flight.
Also an ASN user here...

[EnDSchultz]

Has happened to me sporadically throughout the fleet in the past. Only way to clear it once it gets stuck is to reload plane in flight.
Also an ASN user here...

Indeed. Seems to affect all the Accusim aircraft I've flown. As I said, as long as you keep your pitot heat ON to prevent it from icing up in the first place, you'll be fine.

[BeeKing85]

Ok, thanks for the info. Very much appreciated.

[AKar]

Yes, this has happened to me too. While it makes an interesting flight, I think it may be worth looking into at either A2A's or Hifi's end for any simple cause?

-Esa

[bobsk8]

Sometimes it takes awhile to thaw out, if it freezes up.