Pitot Static line leaks

[Jonathan Alvord]

Ok Im in the process of getting the Plane recertified for IFR flight. What a pain it has been. Found that the altimeter was bad and needed replacing, tried buying a used one but that was not certifiable (was worse than the one I had). Then told I had a leak in the Autopilot (had to send it back to Mid Continent for repair, still waiting to hear from them). Was also told there was a leak in the static line anywhere from the Speedo back to the static ports.

I dove in and applied low pressure air to the static port and could not locate any air leak using baby power (recommended by avionics shop (should I be worried about cancer now? Just kidding). Whats the likely hood of a leaking line or poor seals in Steinair couplers? I'm tempted to just buy some new hose and replace it all.

Jon

[Jake14]

had the same problem, but with the push-on 1/4" connectors the troubleshooting was fairly easy. Make some plugs by filling a short section of the plastic tubing with sealer so you can block off the system at any point. Start with the altimeter only and pull a slight vacuum (carefully! you can attach some coiled-up surgical tubing to the plastic tube and carefully uncoil it to reduce pressure in the line)) to get it to read a couple of thousand feet, pinch it off and note the bleed-down in feet per minute (Should be less than 100ft/min) Keep adding items (VSI, ASI, etc) until you find the problem(s)

ref:14 CFR Appendix E to Part 43 - Altimeter System Test and Inspection

[Bavafa]

Some of those push on connectors seal far better in pressure than vacuum but they have improved very much in recent years but I would not be surprised if one was leaking a bit.

[9GT]

Originally Posted by Bavafa

Some of those push on connectors seal far better in pressure than vacuum but they have improved very much in recent years but I would not be surprised if one was leaking a bit.

I had several of the push on Safe-Air fittings leak when I built my RV-10. I even used the special tool they sell for cutting the lines clean and straight. Re-cut them all and they still leaked. Maybe better quality now but I ended up wrapping every joint with silicone fusion tape before I was able to get a leak free system. Not a big fan.

[Bavafa]

One of the best fitting that I have seen which you can easily disconnect and reconnect without any chance of failure is the parker fittings. The only down side to them is that they are not as small as the push on type fitting.

Leak free guaranteed.


https://www.zoro.com/parker-union-te...Q&gclsrc=aw.ds

[Walt]

My first choice is Nylo seal, I do use the push on fittings sometimes but my go-to is always Nylo.

[FinnFlyer]

Hard to believe but I finally traced the leak to the plastic Tee in the back between the two static ports.

Replaced that and the stiff plastic lines with thick-walled silicone vacuum hose. Also behind the panel.

Using any kind of stiff plastic (nylon, poly..., whatever) is asking for it, in my opinion.

Finn

[NYTOM]

The August 2006 edition of Sport Aviation has a article, plans and instructions for a homebuilt Manometer that is unbelievably sensitive and will detect the tiniest leak. It even has a printable calibration scale to check your airspeed & altimeter.
Good for VFR but obviously not IFR but at least you can check for any leaks if you get suspicious of your readings.

[Walt]

Originally Posted by FinnFlyer

Hard to believe but I finally traced the leak to the plastic Tee in the back between the two static ports.

Replaced that and the stiff plastic lines with thick-walled silicone vacuum hose. Also behind the panel.

Using any kind of stiff plastic (nylon, poly..., whatever) is asking for it, in my opinion.

Finn

I think Van's used to (maybe still does) suggest heating nylon tubing and then pushing onto a nylon 'T', this method is guaranteed to crack the tubing after a few years.