Fuel icing

JohnRichardson

I have had a couple of problems with fuel icing over the last few years in my 1979 Piper Aztec F and wonder if this is a common problem or not. It seems to only affect the starboard outer tank which has a long range tank fitted, and seems to happen when the OAT gets to about -20C. The other tanks don't appear to have the same problem. I solve the problem by adding IPA to the fuel but I wonder why it only affects the one tank?
Does anyone else have the same problem and do you know why it might only affect the one side?

Scott Sherer

Hi John,
Sounds like you have a leak in that tank. Does your cap allow rain in during flight? Check the seal on the cap.

JohnRichardson

I don't think that the tank is letting water in because when I drain before flight there is no water present. Unless of course it is getting caught in some fold in the tank and only releases when I fly.

Scott Sherer

Hi John,
In order to have ice in your fuel you have to have water. So it would seem to be one of these choices:
1. As you said, it's already in the tank.
2. It's coming in when you fly (if you're flying in rain or clouds).
3. It's coming in on the ground (if the plane is outside when it's raining).

Can you think of any other sources?