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Jim

Strange problem with D100 and airspeed

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Also posted on Dynon forums.
 
D100 has 5.5 firmware, is networked with a D120 and is installed in a 2006 CTSW.

Went flying yesterday evening.  Everything was fine during the flight, no reason to question airspeed until I taxied back to the hangar.  Instead of the airspeed indicator going blank as it normally does, it varied between 15-17 knots.  I stopped the aircraft and it was still varying between 15-17 knots.  I pressed the leftmost button to toggle the display screen and the airspeed field immediately went blank as it normally does. 
 
 
 

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It may have been just a glitch and or it may just have needed to be rebooted like a regular computer at times. The other thing is to make sure the #2 yellow "Keep Alive wire" on the D120 has been disconnected or cut. It can cause strange things to happen.

I just had a 2007 CT come in yesterday with this wire connected.

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It may have been just a glitch and or it may just have needed to be rebooted like a regular computer at times. The other thing is to make sure the #2 yellow "Keep Alive wire" on the D120 has been disconnected or cut. It can cause strange things to happen.

I just had a 2007 CT come in yesterday with this wire connected.

 

I'll take a look.  Both the D100 and D120 have worked flawlessly for the last 5 years.  That's why I was a little surprised.  I'm guessing it's a subtle firmware bug.

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Went flying yesterday evening.  Problem is still there and probably not firmware.  We will blow out the static and pitot tubes this weekend and I have a feeling the problem will go away.

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Went flying yesterday evening.  Problem is still there and probably not firmware.  We will blow out the static and pitot tubes this weekend and I have a feeling the problem will go away.

 

Disconnect them from your instruments first to avoid damage!

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Went flying yesterday evening.  Problem is still there and probably not firmware.  We will blow out the static and pitot tubes this weekend and I have a feeling the problem will go away.

 

That would have been my first inclination. 

 

Simple stuff first.

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Disconnect them from your instruments first to avoid damage!

 

Absolutely.

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Any ideas to trouble  shooting this one :    I get a error indicated airspeed only in climb (increased angle of attack)    Straight an level is fine.  But when i climb, obviously i lose airspeed, however my indicated is showing a 15kt- 20kt  difference to GPS (in no wind) -  i.e Climb would be 50kts and GPS is showing 70kts.    

I tried checking stall and i am stalling at 60kts indicted - which i know is really around 40kts.     

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Any ideas to trouble  shooting this one :    I get a error indicated airspeed only in climb (increased angle of attack)    Straight an level is fine.  But when i climb, obviously i lose airspeed, however my indicated is showing a 15kt- 20kt  difference to GPS (in no wind) -  i.e Climb would be 50kts and GPS is showing 70kts.    

I tried checking stall and i am stalling at 60kts indicted - which i know is really around 40kts.     

 

If the pitot probe and pitot drain are blocked but the static port is free then the IAS will increase during a steady climb and decrease during a steady descent.

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Sorry for the late followup.  I disconnected the ports from the instruments and blew the ports and lines out with air.  Everything started working fine again.

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If the pitot probe and pitot drain are blocked but the static port is free then the IAS will increase during a steady climb and decrease during a steady descent.

 

Where exactly would the pitot drain be located on an early model CTLS?

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Where exactly would the pitot drain be located on an early model CTLS?

 

From the POH for the CT:

post-940-0-21225000-1462675962_thumb.jpg

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Where exactly would the pitot drain be located on an early model CTLS?

They don't have one. The system has to be blown out.

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