Fuel leak on nose gear

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Pascal
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Fuel leak on nose gear

Post by Pascal »

Today I went for a short 12 minutes flight to a nearby airport with a pilot friend for lunch.

I was also flight testing my DA20-C1 after installation of the front and back air intake / output baffles of the winter kit. I wanted to verify that the oil temperature and pressure both stayed in or near the green. Outside air temperature on the ground was 2 degrees Celsius and there was a 20 knots cold wind blowing from the north.

I was happy to see the engine parameters all well within acceptable levels.

However when came the time to restart the engine from the trip back, I elected to use the cold start checklist as the airplane had been sitting outside on the ramp in the cold wind for over an hour and a half. I might have primed the engine too much. In any case, after cranking ten seconds and then waiting for the starter to cool down, I managed to start the engine by reducing the throttle to idle and pulling on the mixture.

Then I smelled a faint smoke scent for a second or two. In retrospect I should have stopped the engine and checked but since the smell went away very fast, I thought nothing of it.

The runup, takeoff and flight home were all normal and uneventful. Engine gauges were all in the green, power and rpm appeared normal, and the airplane performed very well, easily flying at over 135 knots indicated in the cold air, which was fun.

However, after landing and shutting down the engine, I noticed traces of 100LL on the nose gear and on one of the three little tubes protruding on the left side near the rear baffles. (See picture). The airplane did not appear to be leaking fuel, even 30 minutes after engine shutdown.

Has anyone experienced this before? If so, what is it? Could it be unburned fuel comimg out of an overflow line? Could it be unburnt fuel coming out of the exhaust that would have come out when I was cranking while the engine had not fired yet?

Could it be something worse, like a failed pump or ruptured fuel line?

Any advice would be appreciated!

Thanks,

Pascal
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CFIDave
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Re: Fuel leak on nose gear

Post by CFIDave »

I think you simply primed the engine too much prior to start.

I've read stories of pilots doing this on Cessnas, for example, where fuel from over-priming leaked out the bottom of the engine cowling and caught on fire after engine start.
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Sandy
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Re: Fuel leak on nose gear

Post by Sandy »

I agree with CFIDave. It’s likely that you overprimed, and excess fuel was blown out or dripped out. I did that many years ago when I had my Warrior. It started a fire, but I was able to get the engine started and suck the flames back into the engine. It provided a few exciting moments for me, and the tower and fire personnel (at KTTN), but there was no damage.

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Re: Fuel leak on nose gear

Post by RMarkSampson »

Also concur - overprimed, those drains are there to handle exactly that.

Per you concern about the fuel pump - not likely but you can always visually inspect it to be sure. I just replaced my engine-driven fuel pump. Low end pressure was getting a bit low at idle. There is an adjustment for that. However, more troubling was the 100LL staining that was on the fuel pump vicinity of the "weep hole" that is suppose to help equalize atmospheric pressure and should have not fuel present. Because of that staining I elected to replace vice adjust. The engine compartment near the exhaust piping is no place for fuel to appear.
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