"Malcolm Teas" wrote in message
om...
Hm. An FAA certified fuel gauge has to be right on two conditions:
full and empty. No assurances of correctness anywhere else.

Illegal cell phones, and now this old wives tale?

It's retread week!

I dunno about that. I'm repeating what I learned from an instructor
of mine who's also an A&P.

Certification rules require at least two things of fuel gauges: that they
read "empty" when there is 0 usable fuel left (as opposed to dry tanks), and
that they indicate the quantity of fuel in the tank.

People commonly misinterpret the "0 usable fuel" clause to mean that's all a
fuel gauge is required to do, but it's simply not true.

I can't speak to the certification rules prior to the current Part 23, but I
would be very surprised if they also only required an indication of empty or
not. After all, that could satisfied with a simple on/off light, and I've
never heard of an airplane so-equipped.

See FAR 23.1337 for more details.

Pete