Essentially there are three types of aircraft fuel gauges – mechanical, electrical and digital (latest). Let's take a look on how each of these work.

The mechanical fuel gauge – how it works:
The mechanical fuel gauge used in aircraft uses a cork (currently the float is made from Nitrile rubber) that floats on top of the fuel. So when the fuel level goes up or down so does the cork. The cork in turn is attached at the end of a light-weight pipe usually made from tempered aluminium. As the cork (or rubber float) moves up or down so does the pipe. The pipe in turn is attached to a delicate gear system usually made from stainless steel. Through use of the gear ... Read more »