Leak Down Procedure (Pic Heavy)

Hipo65 said

I think after doing some resurch that I'm getting diffrent readings is becouse of the psi my gauge set is testing @. His is testing from the more common 100 psi. Mine is testing from 25-27 psi! I bet of I get a gauge set that tests from the more "standard" 100 psi my % goes waaaaay down!

Click to expand...

Even at 100 psi, gauge readings are not going to "compute" very well from gauge to gauge, as there are variables. What you need to do is to get clear back to the ORIGIN of leak down testing

These are sometimes called "differential pressure testers" and reference is made to a "master orifice tool"

7ts0.com/manuals/continental/Service%20Bulletins/MB%2084-15.PDF

Originally, the orifice........which is the key to the whole deal.........was a precision flowed orifice, not just a sharp cornered, rough drilled "somewhere around" .040" hole, with internal flaws and of unknown length, friction, and flow characteristics.

This thing is claimed to be such an orifice

http://www.skygeek.com/aircraft-too...aign=froogle&gclid=CN6AxsDP0cgCFRSEfgodcEEGQA

If you google the part no. in the pdf for the master orifice, it seems to be "unobtainium"

https://www.google.com/search?num=2....0....0...1c.1.64.serp..4.23.1325.oYwL9Vgm65M


A little 'bit from the FAA

http://www.avweb.com/news/savvyaviator/188758-1.html

and yet more

http://www.vansairforce.com/community/showthread.php?t=94870