TLAW

Can anyone out there with intimate knowledge of the Piper Cherokee/Arrow fuel system answer a question for me?

My question is this - does the fuel leave the tank via a short vertical standpipe, leaving the remaining fuel as unusable, or is some other arrangement employed? Is the same arrangement used with the Cessna 172 type?

The reason I am asking is - when carrying out a pre-flight inspection, my current practice is to take a small sample from the drain point under the engine and then a sample from each tank. I heard a differing opinion the other day that by drawing a sample from the engine drain first you risk drawing an untested sample from the fuel tank into the fuel lines. I was under the impression that the fuel was drawn to the engine via a stand pipe slightly above the bottom of the fuel tank, and that the inspection drain point was at the lowest possible point in the tank, making this scenario impossible.

Apologies if I haven't explained this very well, and if this post is in the wrong place.

A and C

First...... the "standpipe" is just a strainer fitted slightly above the bottom of the tank and if the water is above this very low level then the water is already on its way down to the engine.

It would be better to drain the tanks first because you have more chance to isolate the tank that has the water in it and then once disposed of the engine drain can be checked for water

stevef

Just to add that the strainer is horizontal. It's very coarse btw; the fine filters are in the firewall fuel bowl, the electric pump and finally the carburettor fuel inlet.

TLAW

Thanks for that info - my head was just a little too big to squeeze through the filler to have a look. The missus must be on to something