Does water, having been in the fuel tank, smell like AVGAS?
I think you would smell really badly of avgas if you spent some time in the fuel tank 
unless you know what sort of colour to look for (avgas is not all that obviously “blue” – it is just a tint) you could easily think it is all avgas
Until now I took the view that if it looks like AVGAS and it smells like AVGAS it’s AVGAS!! For some odd reason it didn’t occur to me that it might all be water!
Does water, having been in the fuel tank, smell like AVGAS? If it does I think I will adopt Peter’s three drains into a single jar!
The problem I had was that the first several jars were 100% water, and unless you know what sort of colour to look for (avgas is not all that obviously “blue” – it is just a tint) you could easily think it is all avgas. And I did! The instructor however knew better and got me to drain out a few more. Eventually I ended up with the picture I posted.
So, on my plane, I always drain all three drain points into the one jar, each test point filling it 1/3. I am assuming that the probability of all 3 producing 100% water is miniscule 
so if any one of them does it, it should be obvious. I have never seen as much as a single drop of water, thus far…
See this – nobody is immune.
Peter wrote:
I started my PPL in a PA38 which routinely produced this
Many thanks for posting this video and picture. Within fourteen years of flying SEP I have never seen water and fuel together in one sample. Sometimes I felt uncertain of how this looks like.
The video reminded me of something… I started my PPL in a PA38 which routinely produced this
due to perished filler cap seals which the company (a UK CAA charter AOC holder) would not replace because they would cost 20 quid each.
Also, the previous flight has already been a big gamble and you’ve been lucky to have survived it.
dublinpilot wrote:
I can see how for a 5 minute flight, you might be tempted to skip that hassle if you’d reason to believe that there was plenty of fuel there.
If the flight really is that short and you don’t have enough fuel to complete it, you don’t have to climb anywhere – the fuel gauges will read empty…..
I think visually checking the fuel on most high winged aircraft is easier. On a low wing you very often have dihedral and fuel caps at the outboard end. After 1/4 fuel has burned off the tank appears dry when looking through the filler opening. Conversely on my high wing plane I can stand on the tire and stick the tanks all the way to empty… I know exactly how much is on board before every flight.
I very often fill the tanks on my low wing plane before flight… which reduces climb performance but eliminates the concern with visual inspection. I also added a fuel flow totalizer.
dublinpilot wrote:
I can see how for a 5 minute flight, you might be tempted to skip that hassle if you’d reason to believe that there was plenty of fuel there.
I think that the main reason for doing that kind of idiocy is greed. Most of the accidents and low-fuel incidents of that kind I am aware of were caused by people who tried to save money by fueling where it is cheapest. This goes all the way to commercial aviation and airlines… You plan to fly from A to B and onward to C. C has the cheapest fuel, so the plane is fueled a A with the minimum necessary for the round trip. Now there was some headwind between A and B and some delay on the ground before continuing to C and suddenly the plan – that no one re-evaluated during the trip – does not work any longer. Not that it has not happened to me… but never to the point of reaching dry tanks. However pretty close on some occasions…
I wonder is there any correlation between running out of fuel and high wing vs low wing?
Visually checking fuel level on a low wing aircraft is trivial to do a part of the walk around. For a high wing aircraft there is more involved…getting out ladders, and climbing on top, then repeating on the other side.
I can see how for a 5 minute flight, you might be tempted to skip that hassle if you’d reason to believe that there was plenty of fuel there. For a low wing, it’s a trivial part of a walk around. When your by the wing just open the cap and look in.
