[Don]

I'm am debating where to locate my GRT AHRS. My prime location right now is at the first bulkhead behind the baggage compartment. This location simplifies some of the wiring issues but it potentially complicates running the pitot line. I'll need to connect the pitot line to an ASI in the panel (round gauge) and to the AHRS.

My question is, is it acceptable practice to bring the pitot line in from the wing to a tee connector and then run one line forward to the ASI and another line back to the AHRS? Or, should I run the line to one instrument and then to the next?

It seems to me the ram air pressure in the pitot line is probably pretty low and I may be introducing significant friction loss errors by using the tee. On the other hand, I can imagine if the friction losses are low enough it wouldn't matter.

In any event, I only want to run these lines once!

 

[BobTurner]

I had the same issue (air data box in rear). I used a T.
There should be no 'friction' losses because there is very little air flow (just what it takes to compress/decompress the line)-as long as you have no leaks.

OTOH, my static port is aft. It runs to the air data box, then forward to the panel to backup instrument (D6), where it is T'ed to an alternate static valve (to cabin). When I test the alternate static air (normal static port still open) I note aft airdata hardly changes, while the D6 goes 'higher' with cabin pressure. In this case there clearly is flow, and a drop along the line. Just what you'd expect.