Michael wrote:

My Twin Comanche does not have a recording tach, because it has a
single instrument (dual needle) for both engines. Hobbs time would
have meant inspections at unnecessarily frequent intervals. My
solution was to interface an hourmeter to the squat switch using an
isolation relay.

snip

The truly hilarious part of this - in order to get the installation
approved, I generated so much paperwork that the weight of the paper
exceeded the weight of the installed components.

In order to reduce the chance of this happening again, I'd suggest using
lighter paper next time. :-)
http://www.xerox.com/Static_HTML/xsis/lwpaper.htm

Russell Kent