Fuel Gauges: The ‘Only Accurate When Empty’ Myth

Hinzugefügt: 2026-05-26

[00:00:00]Hey there, it's Tuesday. You know what that means? Tom's got the know-how. He's on your screen. Quick little tricks, smart ideas [music] that stick. It's Tuesday Tips with Tom.

[00:00:13]There's a widespread misconception that fuel gauges are only required to be accurate when the tank is empty. This is wrong. Since fuel starvation and fuel exhaustion are by far the leading causes of engine failures in Beech airplanes, a good fuel level indicating system is vital. It's also required by the regulations. So, where does that only accurate when empty myth come from? It's a partial reading of 14 CFR 23.1337, the regulation concerning certification of fuel indicating systems.

[00:00:44]True, paragraph B.1 of this regulation says, "Each fuel quantity indicator must be calibrated to read zero during level flight when the quantity of fuel remaining in the tank is equal to the unusable fuel supply." But, the full regulation includes this: 23.1337, "Fuel quantity indication. There must be a means to indicate to the flight crew members the quantity of usable fuel in each tank during flight." "An indicator calibrated in appropriate units and clearly marked to indicate those units must be used. In addition, each fuel quantity indicator must be calibrated to read zero during level flight when the quantity of fuel remaining in the tank is equal to the unusable fuel supply. In other words, if a gauge does not indicate a steady reduction in fuel level as fuel is burned or does not correctly indicate approximately full, 3/4, 1/2, 1/4, top of the yellow arc as marked on the fuel gauges, it violates the regulation and must be repaired.

[00:01:44]Except for the 58P and 58TC, all Bonanzas, Barons, Debonairs, and Travelers were certificated to the old Civil Air Regulations Part 3.

[00:01:53]CAR 3.672 was almost identical to the later part 23 requirements. If your fuel gauges aren't accurate and reliable, fix them.

[00:02:03]Not only is it required by the regulations, it's an important component of fuel monitoring that helps prevent all too frequent fuel management related crashes. There's information on fuel gauge troubleshooting and repair on the aircraft technical information pages of the American Bonanza Society website.

[00:02:20]I'm Tom Turner. Thanks for taking 2 minutes to learn more about your Beechcraft.