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NPT fitting for AHRS

Tankerpilot75

Well Known Member
I’m thinking about upgrading my old WS units to one Horizon EX and one Sport EX. The Sport EX would replace my lower WS unit which I generally use as a MFD and the Horizon EX replacing the upper WS as my PFD.. The Sport EX has an internal AHRS unit while the Horizon EX utilizes my existing external AHRS. By installing the Sport EX I gain a second AHRS as a backup.

Here’s my uncertainty. This combination will require breaking into my pitot/static system and plumbing new hoses and connections for the Sport EX. Since I’m not the original builder I am not sure where to source the required 1/8” hose and NPT connectors. Where do you recommend?

Also if I break into the pitot/static system doesn’t that require a new Part 91.411 pitot/static check by a FAA certified inspector?
 
Hi Jim,
I mail-ordered pitot-static tubing and hardware from Stein (SteinAir, look for his ad on this forum). Make sure you know the diameter of the existing tubing.
Yes, strictly speaking, a new pitot static test is needed. Now, here’s what I do (I am not a lawyer): The regs say, ‘following any work where a leak might be introduced, a new test....’ (something like that). So after the work I just test for leaks (use a water manometer). If there are none, then my work didn’t introduce any leaks, so I feel I’ve met the intent, if not the letter, of the law. Or, I once planned ahead and installed a new transponder-just before my scheduled biennial pitot-static test.
 
BTW, Stein also sells an inexpensive razor blade cutter that does a nice job of making clean, square cuts of the vinyl tubing.
 
Same here - bought all the pitot/static stuff from Steinair - he's got lots of cool stuff that works well. The colored tubing is very cool, too. The tubing cutter is nice, but I had to add some rough surface tape onto it - it was trying to slip out of my fingers. Looking at the photo on his website it looks like they added some ridges, so probably all good now.
 
The big box stores also have various sizes of polytube and connectors. I bought all my stuff from MSC, including the slick Parker pushlock, quick release fittings that makes tube connections a no tool affair.
 
I'm curious about the "breaking the pitot-static system" comment. I just did an avionics upgrade and had to plumb a new ADAHRS. New AoA line, "T" into the static system, and "T" into the pitot line, all using PTC connectors I got from Stein. I certainly see the wisdom of a pitot-static leak test, but it's it's required only for IFR flight, correct?
 
Definitely get the stein tubing cutter for clean square ends. Also, the tubing is stiff as elephant hair - in the tight spaces under the panel, I used a heat gun (practice 1st) to straighten and form nice radius bends for the tubing to ease the loading on the components. You will see the issues.

Don't worry about more connections, plan the job for ease of assembly. Then after you are done, make a manometer and (after checking the manuals) pressure test the system for leaks. LOW PRESSURE. I found a 3cc syringe plunger jut right for the low pressure and volume needed. Also, be critical and cautious of the test apparatus leaking. It was most troublesome for me.
 
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