I have heard this repeated for quite a while, and I can't find the pertinent
section of the aircraft certification regs.  Would you mind posting the chapter
and verse where I can find this requirement?
Jim
The only requirement is that
-when the tanks are empty, the gauges read empty.  If they show full when
-the tanks are 1/4 full, that is not a problem in so far as the FARs are
-concerned.
Jim Weir    (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST   Pres. Cyberchapter   EAA Tech. Counselor
http://www.rst-engr.com