The pilot reported that he took off from his private airstrip and flew for about 30 minutes before landing at a nearby airport for fuel. After fueling with 24 gallons of fuel, he did not perform a pre-takeoff run-up of the engine and departed the airport.
About 1.5 miles from the airport in Curtis, Nebraska, the Cessna 170B’s engine sputtered and lost all power.
The pilot performed a forced landing to a small field. During the landing roll as the airplane was approaching the end of the field, he applied heavy braking, which caused the airplane to nose down coming to rest on it nose. The airplane sustained substantial damage to the left outboard wing.
After the accident the pilot sampled the fuel from the wing tanks and gascolator. The fuel sample from the gascolator was about one-half water and one-half fuel. The wing tank samples contained all water.
The pilot gave investigators photographs of the airport’s above ground fuel tank, including photographs of the interior of the tank. The tank interior showed a large amount of rusted metal in the bottom of the tank.
The airport manager reported that the airport fuel tank was about 30 years old and was of double wall construction. Water had entered the space between the inner and outer walls of the tank and the inner tank had rusted by allowing water to enter the inner tank and fuel supply. The tank did not have filtering on the outlet.
The airport ordered a new tank and planned to include filters on the outlet, including a water separating filter.
Probable Cause: Water contamination of the airplane’s fuel supply which resulted in a total loss of engine power.
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This April 2021 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Simple basics 101.
Sloppy FBO….sloppy pilot.
When the fellow had his C170 filled up, any water in the fuel would have been detected at the wingroot quick drains almost immediately. It wouldn’t have migrated to the strainer drain or the carburetor bowl, as the engine hadn’t yet been run, and all the fuel lines would have been full of fuel. It’s always a good idea to sump the wingvtanks a few minutes after refueling anywhere.
As for the airport’s above ground tank, it sounds as if the fuel pick up was at the very bottom of the tank…..not a good design. That pick up should have been several inches from the bottom, and the tank itself should have had a fuel sampling valve at its bottom. Any above ground tank is susceptible to condensation with its interior!
I’ll never forget when I was training with someone in his Mooney and we refueled at the airport where I was based after having flown already and hour or two. The aircraft owner checked fuel only a few minutes later and got quite a bit of muddy looking water in the samples. Best I can remember it took about eight samples on each side to get nothing but clean fuel and we continued our training without incident.
Feedback from the FBO revealed that the seal on the top of the fuel truck had failed. The day or night before, there had been a dirty rainfall, and apparently (many years back) the truck’s fuel load had not been sampled after the rainfall. But it explained the muddy looking samples from the airplane. At least in this model, the water appeared quickly (may take more time in others) in the samples after refueling and I think any fueling should be followed by a fuel check 100% of the time.
I’m curious. If the pilot had done his run-up would it have caught the problem in so short a time? Also, how long would it take for the contaminant (water) to have made its way to the sump(s)?
And does this imply would should check our sumps after every fill up at every airport every single time?
The Gatz fuel sampler comes in 2 sizes, 12 ounce and 16 ounce.
Buy the 16 ounce size and fill it up. It’s not a waste of money. It has a screen in the top opening for rerurning the fuel to the tank if it passes your inspection.
The ASA fuel cup is the size of a shot glass and (it seems to me) has less chance of detecting contaminants in the fuel.
Its a good practice to give some time after fueling for anything to travel down and settle and then sample your fuel prior to starting and departing.
How much time is “good amount of time”? Thanks.
It only takes a minute or 2 for any water to flow to the low points in the tanks, and usually where the quick drains are.
When I find water in the tanks after a sample, I’ll go to a wing tip and rock the wings to be sure all the water gets to the drains. Then continue to sample and ‘rock’ until no more water is found.