green fuel from colocator

[ahmebane]

I was about to fly my DA40 today & during the preflight I noticed that the fuel I drained from the fuel strainer on the bottom of the fuselage was a light green color. The wing tanks were draining the normal light blue. I ended up draining about a pint, maybe a bit more, of green fuel before it started coming out blue.

The plane was last flown 3 weeks ago, last fueled 5 weeks ago. (Personal issues have precluded me from flying much lately). The plane has the extended-range tanks & has 30-35 gallons of fuel remaining.

I talked to my shop foreman and he has never seen anything like it. It smelled like gas & he did not think it had jet fuel mixed in. Didn't have the jet smell or feel. It did not look like water contamination - I'm in San Diego where water is rarely an issue & whatever the green substance was, it did not look like water - it was quite well mixed.

Any ideas? I am not flying it until I understand whats going on. The only thing I can think to do at this point is to have the entire fuel system flushed.

TIA.

[Steve]

Holt:

I don't know what it is, but green usually means copper. The fuel drain is made of brass, and I wonder if you could have some internal corrosion in the drain that has colored the fuel. I doubt misfueling, since a) the samples from the tanks drains are blue, b) they haven't produced 100/130 avgas in decades (green), and c) any other type of fuel mixed with 100LL should drain colorless (the only clear fuel is biodiesel).

If it were my aircraft I would shut off the fuel selector and pull the fuel strainer bowl, with special attention directed to the brass drain valve. Let us know what you discover.

Steve

[Davestation]

I can only imagine that something got trapped in the gascolator filter and dissolved.

I’ve read stories of fuel trucks changing their filters and the dye in the filter discoing into the fuel or brand new hoses and oils in the rubber leeching into the fuel - but then all your fuel would be green and not just that one area.

[ahmebane]

OK, problem more or less resolved. The shop pulled the gascolator, no corrosion. They put the fuel filter & the drain in separate tubs of clean avgas to see if one of them was causing the discoloration. They noticed a "white flaky substance" coming out of the fuel filter after it sat a bit. They then cleaned a fair amount of whatever the gunk was from the filter. After a thorough cleaning, reassembled everything & let the plane sit overnight. No discoloration now. So it seems like something got into the filter that was then leaching into the gas. No clue what the substance was.

I fairly recently purchased the plane & it hasn't flown a ton since arriving. It was flown to San Diego from Pennsylvania & of course refueled a number of times along the way. Maybe something got into the fuel system on the way out? In any case, it seems to be OK now. I'd like to know what was gunking up the filter, but I dont thats gonna happen.

[ahmebane]

A bit more info: After talking to the shop manager, they think some water accumulated in the bowl over the last few weeks & then some sort of biological growth occurred in that water. Made the avgas turn green.

Took the plane out today, flew perfectly, no issues.

[danno2000]

I was about to fly my DA40 today & during the preflight I noticed that the fuel I drained from the fuel strainer on the bottom of the fuselage was a light green color.

First thought I had was back to ground school. Is there any chance any FBO is still using high lead 100 Avgas, which I confirmed in my notes was apparently dyed green? I’ve never actually seen any.

dan

[Lance Murray]

I am in San Diego also. Where are you located? Who fueled the airplane last? Years ago I got a load of water in a King Air that flamed out an engine. Turns out the FBO was not following standard procedures with their fuel truck and I got the first fill after the truck was returned to service after two weeks with the truck drained empty for maintenance. The truck was refueled and they then fueled my airplane. Unfortunately they didn’t sump the truck and likely put a large amount of water in my tank.

Same sequence caused a twin-Otter to crash at Perris Valley killing 16 Skydivers and the pilots in the 90’s

Despite what we are taught water and or Jet-A is very difficult to detect in 100LL. If I were you I would go to the FBO and ask to see records of the fuel truck for the day and days preceding your last fill-up. If they refuse to show you do not use that FBO for fuel again.

[ahmebane]

I'm based at MYF. Gibbs fueled it, but as of now that was almost 6 weeks ago. There were no other reports of water/contaminants that I could find. There is no 100 high lead gas sold on the field - that was my first thought, but its not even available. After cleaning the fuel filter the problem has apparently been solved. No discoloration for several days & I flew it on Friday for an hour with no issues.

[Lance Murray]

It's still worth getting the fuel truck records just for piece of mind and also if there was a problem then Gibbs would be aware that they failed procedures.