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Failed Pitot/Static test need suggetions

Rick_A

Rick_A

Well Known Member
I had an avionics shop do my first P/S test today and it failed big time. I had a huge leak in the static system at the "T" where the static ports join together and transition to semi-rigid line. I'm using Vans static system for this portion of the system.

The big problem at the "T" was that one of the connections had come completely off the T and I had not noticed. I suspect the other one was leaking too.

So my first question is: Vans system uses very small (I think it's 1/8" ID) tubing off the pop rivit static ports. What's the best way to "T" these together and then connect to the hard nylon tubing that runs forward?

Second question. I observed that when I got my Altimeter back from it's calibration test that the avionics shop put teflon tape on the on the static port fitting. I did not use teflon tape on any of the nylon fittings that I installed. Is this standard practice and should I remove and reinstall the fitting to all my instruments and AHRS using teflon tape?
 
Rick,

This was a long time ago, but I believe that the small tubing was joined with a push-on "barbed"-type T-fitting. AS for Teflon tape, I have sued it, and not used it, and gotten good results wither way. The nylon is so slippery anyway that I am not sure what is sealing what....

Paul
 
Same failure

I had the same failure. Also, with just a small tug, the line came off the port. The tech wouldn't certify it with the Van's setup.

Ordered 2 aluminum static ports from AS, nyloseal fittings that screwed into the ports, and a nyloseal T. Used the remaining hard nylon tubing from Vans.

No leaks, certified to 20K feet and it will take a BIG pull to disconnect now.

No teflon tape either since nyloseal fittings go into the instruments, not brass.
 
Webb said:
... Also, with just a small tug, the line came off the port.....
Click to expand...

Did you connect the nylon tubing to the port, or the vinyl tubing? I have vinyl tubing that connects to both ports and the T. The nylon tubing is inserted into the T and goes to the instrument panel.

Also the instructions say to dab some proseal around the vinyl tubing/static port interface, which I did. Have not tugged on it, but doubt it would easily come off.

As for leakage at the T... I hope not. It is on there so tight, that I don't think I'll be able to remove the nylon tubing without cutting into it.

I would suggest builders do their own static/pitot tests first. Once all leaks are fixed, then call someone to $certify$ it.
 
Last edited:
The connection at the port (i.e. pop rivet) is holding, it's making the transition from the 1/8" ID vinyl tubing to the 1/4" ID Nylon (semi-rigid) tubing that was the big problem.

I'm glad to hear that I don't need teflon tape on the Nylon barbs - it's be a real pain to get to my
AHRS and AP fittings.

I think what I'm going to do is order a couple of 1/8 x 1/4 reducers that I found at US Plastics. I'll put the reducers in fairly close to the ports. Run 1/4" ID Tygon to a T and also use the Tygon to make the transition to the Nylon tubing going forward.

Also, I only have 2 compression type fittings on my instruments (the rest are barbs to Tygon), I think I'm going to replace these with the fitting that Stein sells.

The compression fittings I'm using are Nylo-seal fitting with Nylo-seal tubing. As far as I know, the Nylo-seal tubing does not require the use of "inserts" (type 259-N) to make a good seal - I tried to put some in thinking it might help but the inserts won't go in the Nylo-seal tubing.

I really wish I had tested all this before I rivited on the top skin - I just could not figure out how to make a good test rig.
 
Rick_A said:
I think what I'm going to do is order a couple of 1/8 x 1/4 reducers that I found at US Plastics. I'll put the reducers in fairly close to the ports. Run 1/4" ID Tygon to a T and also use the Tygon to make the transition to the Nylon tubing going forward.
Click to expand...

I would recommend going to your local auto parts store and looking for vaccum fittings. I found a package of assorted barbed fittings for around $5.00. Specifically I was looking for one that I could use for connecting my MP transducer to Van's firewall penetration MP fitting.

FWIW, I used Van's static port kit and followed the plans. 200 hours, no problem.
 
How to get a vacuum

If you want to do your own leak checks then the intake naifold of your car can be used to great effect...Start the car..pull off one of the many 1/8th or 1/4 inch hoses and run tygon tubing to your static ports.

You can crimp the tube.

Should pressurise the pitot side to prevent the disphram in the ASI from being stressed...

Be careful.

Frank
 
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