Water in Fuel Tanks

Source: www.pilotworkshop.com/tips/water-tanks, Featuring Bob Martens

Subscriber question:

"Is it OK to fly after draining water from my fuel tanks, or should I have a mechanic inspect the airplane first? How much water drained from my fuel can I tolerate?"
- John L.

Bob:

"The truth is that you don't want any water in your fuel tank!

A quick story.....on a training flight in Connecticut, a student kept getting water in the fuel sample. After multiple attempts, he got a clean sample so they tried to takeoff. The engine sputtered and quit on takeoff roll, so they drained some more fuel. On the next takeoff the engine quit just after airborne. They crashed! The investigation revealed a mix of water and fuel in the tanks. The fuel source at the airport had been contaminated.

If you find water in your tanks on preflight, how do you determine how it got there and when is it safe to fly?

This is not a call to be made by a pilot. A certified mechanic should determine that the aircraft is airworthy.

The downside on this one is pretty bad."