Dynon AOA Probe leak check

[f16bmathis]

My airspeed seems to lag behind reality, so I used a syringe and surgical tubing (highly advanced technical stuff) and connected it to my Dynon FlighDek D-180 and the Dynon AOA probe (no heat). I can get it to go to 100kts, but it dropped off suddenly. So i bypassed the AOA / pitot probe and ran it up to 100 kts, and it HELD! OK, it went down VERY slowly. Went back to the probe, covered the leak vents and the AOA port, and ran it up again, and it bled off the airspeed withing a second or two.

Should the Pitot leak with the AOA and bleed ports covered up? I'm thinking no, and I need to purchase another $245 probe. Thoughts? I will have video up on you tube soon, search Zodiac Zenith 600XLB AOA leak check.

 

[GKC Aviation]

No, if you have the AoA port and the vents covered, it should not leak.
Pitot leaks are pretty easy to find. Drop the probe out of its mast still connected to the pitot tube. Give it some pressure and squirt some soapy water around the probe. The bubbles forming will show you where the leak is.

 

[Dynon]

There have been a couple of designs over the years. Our pitot, even with the vent ports covered up, will not fully seal by design. From the AOA installation guide:

Note that the amount of leakage is not enough to change readings, but it may require that you connect upstream of the pitot to test the equipment.

 

[GKC Aviation]

But it shouldn't surely bleed off 100kts to zero in a second or two, as is happening here?

 

[jakej]

But it shouldn't surely bleed off 100kts to zero in a second or two, as is happening here?

Maybe someone accidentally damaged the internal pitot tube when drilling holes, prior to tapping, for the attachment screws ?

 

[f16bmathis]

I'll try the soapy water test, in the end, I may just buy a new probe to make sure everything is OK.

 

[f16bmathis]

With the Dynon probe having all that rubber calk inside, can I scrape that out and refill it after leak checking? Probably best just to get a new probe. I'm betting a tube was drilled into. I can't see it dropping that much after taping the weep holes. Used to do this on F-111's and F-16's.

 

[jakej]

If you want to absolutely confirm where the problem is just put the probe (you’d have to remove it anyway) in a container of water & blow into the pitot tube - if air bubbles come out of the screw holes then you have found & confirmed where the fault is.