What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Finding pitot/static leak?

MacCool

Well Known Member
I replaced my AFS 4500 EFIS with an AFS 5400. As a result, avionics are now on a Dynon SV network. That's great...but it did require re-plumbing the pitot/static/AOA systems to a remote ADAHARS, which in turn required additional tubing and some new connectors/T-connectors. When I later had my avionics guy do a leak test, there was just (barely) enough of a leak in the system to cause it to fail an IFR check.

My plane is now stripped down for condition instection and I thought I'd try to track down the leak. Any suggestions as to how I might go about that? Is this a soapy-water kind of process? Other systems, tools, or tricks I might use? Surely Amazon, Stein, or Spruce has something I need to buy to solve this problem...:)
 
I am not sure what kind of connector/T-fittings you are using? If it is a barb type fitting or any similar, I would highly recommend to remove them all and replace them with the type that more or less guarantee a good seal and ease of removal, this includes at your static port. If your static port are the pop rivet type, that is a good candidate for leak.

If you are sure of your connectors, then it would be a process of elimination. Harbor freight has an inexpensive vacuum pump that is perfect for this. Disconnect from avionics and keep going towards the static ports. It will not take long to find it.

https://www.harborfreight.com/brake-bleeder-and-vacuum-pump-kit-63391.html
 
Static leak troubleshooting

I replaced my AFS 4500 EFIS with an AFS 5400. As a result, avionics are now on a Dynon SV network. That's great...but it did require re-plumbing the pitot/static/AOA systems to a remote ADAHARS, which in turn required additional tubing and some new connectors/T-connectors. When I later had my avionics guy do a leak test, there was just (barely) enough of a leak in the system to cause it to fail an IFR check.

My plane is now stripped down for condition inspection and I thought I'd try to track down the leak. Any suggestions as to how I might go about that? Is this a soapy-water kind of process? Other systems, tools, or tricks I might use? Surely Amazon, Stein, or Spruce has something I need to buy to solve this problem...:)


Thoughts from someone who hasn't fully isolated his leak yet, but has it queued up to coincide with the next CI, as you're doing. Soap bubbles aren't going to work on a vacuum, and I'm not sure you want to pressurize the static line--at least on segments that include instruments. I bought an inexpensive (~$20?) "brake bleeder/vacuum pump" from Amazon. If the needle doesn't hold steady on the gauge when a light vacuum is applied, you know that you're in the right area.

My plan was to start with "big" areas, and then refine the search. I've completed the first test, as it didn't need significant disassembly for access. I taped over the static ports to start. My -10 has the static line feeding along the starboard side of the fuselage toward the panel. Essentially where it exits the side panel to snake behind the instrument panel to the EFIS, AP, etc..., there is a tee. Disconnecting the aft line from that tee and applying a vacuum showed that my leak is aft of that point. So, I not only need disassembly in the back, battery removal, etc... I also need a skinny 10 year-old who is handy with mechanical stuff. I have doubts whether I could crawl back there, but if successful, I'm pretty sure that I'd never get back out! To minimize the potential for fuselage skin damage, I will be placing a furniture pad, then some pieces of thin plywood that I've cut to fit each of the bottom skin areas between the bulkheads (2 in each of those areas--the plywood will butt against the bellcrank ribs), topped with a second furniture pad. The tail will be supported at the tail tie-down, and also with a padded sawhorse beneath a bulkhead between there and the cargo area bulkhead. My next test will probably be at the tee which connects the static ports to each other and the line running forward. That should tell me if there is a leak in that forward-running line, or (more likely is my guess), at the connection(s) to one or both of the static ports themselves.

Given the location of my leak, I didn't need to worry about applying too much vacuum as long as the line further forward wasn't getting vacuum. If it hadn't been there, I would have been very careful to not create too great a vacuum, which could potentially damage instruments. I would think that just enough to raise the altitude by a few thousand feet would be sufficient. By trial and error at various points (additional tees and/or instrument connections), you should be able to localize a leak .

Good luck finding it quickly!
 
I replaced my AFS 4500 EFIS with an AFS 5400. As a result, avionics are now on a Dynon SV network. That's great...but it did require re-plumbing the pitot/static/AOA systems to a remote ADAHARS, which in turn required additional tubing and some new connectors/T-connectors. When I later had my avionics guy do a leak test, there was just (barely) enough of a leak in the system to cause it to fail an IFR check.

My plane is now stripped down for condition instection and I thought I'd try to track down the leak. Any suggestions as to how I might go about that? Is this a soapy-water kind of process? Other systems, tools, or tricks I might use? Surely Amazon, Stein, or Spruce has something I need to buy to solve this problem...:)

I would disconnect/plug all instrument connections, then apply low positive pressure and do a soap test. That will at least eliminate/reveal if the leak is in the plumbing itself.
 
I would disconnect/plug all instrument connections, then apply low positive pressure and do a soap test. That will at least eliminate/reveal if the leak is in the plumbing itself.
Some connectors seal better under positive pressure than negative. This type of test might not be as conclusive as a test with negative pressure.
 
Some connectors seal better under positive pressure than negative. This type of test might not be as conclusive as a test with negative pressure.

You are correct. I would think/hope that with the very small pressures/vacuum we are talking about, it would be very minor as the pressure is too small to cause flex in the tube/fittings.
 
Garmin pitot

Pitot or Static leak??????
Do you have a Garmin pitot tube.
My Garmin heated pitot tube has a built in leak. Garmin, and the FAA, agree that it is supposed to leak.
 
pitot static leak checks

Just went through a search for leaks in my pitot static system. I started by reading the multiple post already written and learned some before and some after of what to do and what not to do. After I tried to check to see if I had leaks by blowing on tubes in the pitot system, I learned, never blow on the pitot system with an instrument attached as one may damage the instruments or the ahrs (airspeed, altimeter). Fortunately, I only blew with minimal pressure and I did not damage my system by trying to fix it. Also fortunately, we have a great number of really smart, knowledgeable aviation experts on this forum who have helped a not so smart aviation enthusiast.

I had available to me a simple manometer , made from a ½" vinyl tube (from lowes) with a yard stick mounted on the center of a vertical board. I did not know how to use a manometer but after a few tries and a little instruction, it worked like a charm, especially to see if your system would hold pressure.

My system is connected with 1/4" standard nylon tubing. I have a G3X, gap 26 heated pitot/AOA probe, GSU73 and GSU25 and a G5. I learned from our aviation experts to read the manual first, then disconnect the ahrs and G5 and check the legs to see if there were leaks. My connectors are push to connect (PTC) which I purchase at the same time as my instruments from Stein Air. I also purchsed som PTC from a local distributor that sell Parker PTC. All PTCs are quality and all PTC were solid and leak free. I learned the hard way that I thought one would need to disassemble parts of my RV7 (such as the wing root fairing and floor where some connectors joined) but if you will check from the ahrs, and G5 to the probe or the static ports (tape over the ports) first using the manometer and about 15" of water, if it holds steady, the no leaks. Also learned that one must cover the pitot tube (good seal) with both openings in front and tape over the bottom drain holes and AOA hole (my probe has 3).

The gap 26 (per manual) allows some leakage and again I learned the hard way ( I removed the probe and checked for leaks using a bucket of water but careful with the wiring) that my probe leaked what I thought was a lot. I really found my leak in the flare fitting at the end of the probe, that I allowed to loosen. When I reconnected everything (wing fairing, floor and probe) I found another leak at my GSU73 where I had a Tee with a physical fitting I had allowed to loosen. I added a little liquid teflon to the physical fitting and reconnected it. During my testing, I found it much easier to use a small amount of 1/4" vinyl tubing (lowes) when connecting to the PTC and the manometer. I used a large syringe to add water to the manometer to increase pressure (simply convenient and easy to increase the pressure in small amounts). When checking the PTC that were physically attached to the ahrs and G5, I would bring the airspeed up to 130-150 to make sure it did not leak (manual will allow some drops). Also learned that a golf tee works perfect to tap off a leg on tubing or a short vinyl tube with golf tee to check a PTC tee.

I do not think soap will work as easy or conclusive as the manometer and from my experience (soap before manometer) a lot messier and very hard to really see, especially a low pressure. If I had been smart enough to start from the ahrs/G5 and track backwards, I would have save a ton of time, effort and some blood as my RV has no sharp edges, screws and always plenty of room so that I never get scrapes and cuts.

Hope this will help some other not so smart aviation enthusiast.
 
Just went through a search for leaks in my pitot static system. I started by reading the multiple post already written and learned some before and some after of what to do and what not to do. After I tried to check to see if I had leaks by blowing on tubes in the pitot system, I learned, never blow on the pitot system with an instrument attached as one may damage the instruments or the ahrs (airspeed, altimeter). Fortunately, I only blew with minimal pressure and I did not damage my system by trying to fix it. Also fortunately, we have a great number of really smart, knowledgeable aviation experts on this forum who have helped a not so smart aviation enthusiast.

I had available to me a simple manometer , made from a ½" vinyl tube (from lowes) with a yard stick mounted on the center of a vertical board. I did not know how to use a manometer but after a few tries and a little instruction, it worked like a charm, especially to see if your system would hold pressure.

My system is connected with 1/4" standard nylon tubing. I have a G3X, gap 26 heated pitot/AOA probe, GSU73 and GSU25 and a G5. I learned from our aviation experts to read the manual first, then disconnect the ahrs and G5 and check the legs to see if there were leaks. My connectors are push to connect (PTC) which I purchase at the same time as my instruments from Stein Air. I also purchsed som PTC from a local distributor that sell Parker PTC. All PTCs are quality and all PTC were solid and leak free. I learned the hard way that I thought one would need to disassemble parts of my RV7 (such as the wing root fairing and floor where some connectors joined) but if you will check from the ahrs, and G5 to the probe or the static ports (tape over the ports) first using the manometer and about 15" of water, if it holds steady, the no leaks. Also learned that one must cover the pitot tube (good seal) with both openings in front and tape over the bottom drain holes and AOA hole (my probe has 3).

The gap 26 (per manual) allows some leakage and again I learned the hard way ( I removed the probe and checked for leaks using a bucket of water but careful with the wiring) that my probe leaked what I thought was a lot. I really found my leak in the flare fitting at the end of the probe, that I allowed to loosen. When I reconnected everything (wing fairing, floor and probe) I found another leak at my GSU73 where I had a Tee with a physical fitting I had allowed to loosen. I added a little liquid teflon to the physical fitting and reconnected it. During my testing, I found it much easier to use a small amount of 1/4" vinyl tubing (lowes) when connecting to the PTC and the manometer. I used a large syringe to add water to the manometer to increase pressure (simply convenient and easy to increase the pressure in small amounts). When checking the PTC that were physically attached to the ahrs and G5, I would bring the airspeed up to 130-150 to make sure it did not leak (manual will allow some drops). Also learned that a golf tee works perfect to tap off a leg on tubing or a short vinyl tube with golf tee to check a PTC tee.

I do not think soap will work as easy or conclusive as the manometer and from my experience (soap before manometer) a lot messier and very hard to really see, especially a low pressure. If I had been smart enough to start from the ahrs/G5 and track backwards, I would have save a ton of time, effort and some blood as my RV has no sharp edges, screws and always plenty of room so that I never get scrapes and cuts.

Hope this will help some other not so smart aviation enthusiast.
Helpful post...thanks for taking the time.
 
Back
Top