Vent: whole pitot static test went sideways over a bad ground strap

Tbh I was out at KSDL last Tuesday doing a routine pitot static check on a Cessna 172. Everything looked fine on the test set until I pulled the static port cover off and the readings started jumping like crazy. Turns out a previous shop had left a corroded ground strap on the transponder, and it was bleeding noise into the air data computer. I spent 3 hours chasing it with a multimeter before I found it, replaced the strap for $12, and the test passed first try. Has anyone else had a small ground issue wreck a whole certification run, or is it just my luck?

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foster.jordan1mo ago

Used to blow off ground straps as a non-issue, figured a bad one just meant a weak signal at worst. Then I saw a corroded strap tank a whole pitot static run like yours, and it took me two days to figure out it wasn't the test gear. Now I check every strap first before anything else, it's the cheapest fix that saves the most headache.

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