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Sumping your fuel system

J

jim plaster

Well Known Member
We had an interesting situation at our local airport happen last week and feel its worthy of noting here...especially since another airplane was severely damaged. We had a gentleman fly up from Florida for an overnight stay at his parents house here in nc. He purchased fuel and took his mom flying and had an un eventful flight. Worthy of noting ...I purchased fuel right after he did. Next morning it was 22 degrees f. And he had planned on flying home to Florida. He preflighted (?). ...which supposedly included sumping the tanks....he also had to jump start due to a dead battery. He warmed up ....did his run up and taxied out. Once he cleared the departure end of the runway things went south FAST! It started running rough....surging as well... Lucky for him he had enough intermittent power to maintain altitude / airspeed to make the dreaded 180 back to the runway. Touching down fast and overrunning the end of the runway...all three gear collapsed on the airplane,luckily no one was hurt. Investigating further we found the gascolator on the firewall inaccessible with the cowl on the aircraft...( if you're going to mount one...at least make it accessable on your preflight). Had this been done during the build,and drained prior to the flight ,we wouldn't have drained nearly 8 1/2 ounces of water from it post flight. Has anyone ever had water freeze in their gascolator or sump? If this could happen we could have a false negative on a preflight water inspection while sumping. This could have contributed to what happened here....all the while it began melting on the warmup ...finally making it to the engine on takeoff... It wasn't an RV and was a injected lycoming....details haven't been released yet so I'll leave that to the Feds.....I later sumped my ship,since I hadn't flown since buying fuel and found no water at all.....be careful folks....check that sump!
 
I have pulled a few airplanes in for inspection during the winter and found gascolators frozen nearly solid with a thin layer of gas on top of the ice. I ask if they've been dumping and I get the blank look.
 
any variations on this sump?

I recall 'sumping' one bird by pulling a knob in the cabin. You were supposed to then go out and look at what splashed on the ground, to see if there were any little blobs of water puddled with the fuel. ( yeah, doesn't work on grass, or sand, or dirt, or windy days, or......etc.)
..never did like that thing, but wonder..... is such an item common? .......perhaps on FI installations ......or one manufacturer.
(was it on a Tomahawk?....or Robin? something I only flew a couple times anyway)
 
How to Sump gascolator?

The only way I can get anything to come out of the gascolator sump on my -9A is when the electric fuel pump is running. Is that normal?
 
Automotive has used a sock for many years to separate water from gasoline. The sock gets
wet with water but the gas goes right through. I guess the plugging potential is a higher risk factor, as long as we have "sumped" for the majority of the water.

Does anyone have some experience with this for aviation?
 
BillL said:
Automotive has used a sock for many years to separate water from gasoline. The sock gets
wet with water but the gas goes right through. I guess the plugging potential is a higher risk factor, as long as we have "sumped" for the majority of the water.

Does anyone have some experience with this for aviation?
Click to expand...

No personal experience, but I suspect if the sock gets saturated (i.e., lots of water in the system), water will come through. Would be good to hear from someone who knows the answer to this.

Greg
 
Fuel strainer

In the automotive systems the strainer keeps chunks out of the fuel system/ pump- but will not prevent water passing through. It might discourage water passing but will not prevent it.
 
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