Fuel Testers & Gauges for Aircraft

You should sample fuel from every sump drain before each flight and again after every refueling, because water and sediment settle to the bottom of the tank where the drains are located and can collect at any time.

A fuel tester reveals water, dirt, rust, and sediment in the sample, and the clear tube also lets you confirm the fuel is the correct color and grade for your engine, such as blue 100LL AVGAS or clear-to-straw Jet-A.

Yes, aircraft fuel testers are fully reusable; you draw a sample, inspect it, then either return clean fuel to the tank or dispose of contaminated fuel and wipe the tester for the next use.

A fuel tester draws a sample from the sump drain so you can check fuel quality and contamination, while a fuel gauge such as a calibrated dipstick measures how much usable fuel is in the tank; many pilots carry both.