Anti-freeze for Avgas

[fltcom]

Operation in cold temperatures occaisionally call for the addition of 2% Iso Propyl alcohol to avgas to prevent ice crystallisation of any water content. Has anyone experience of operating in the minus 9 to minus 15 C range, and should we be considering additives at these temperatures? We know the fuel supplied locally does not contain any.

Cheers

Flt

[Malcolm G O Payne]

My memory is fading a bit, but I am pretty sure we used ant-freeze additive as a matter of course on our C421 abouttwenty years ago and had no problems.

[H.Finn]

I have exactly the same recollection about the same type of aircraft and roughly from the same time period as MGP. I seem to recall the stuff we used was called something like "Shell Compound 6". What it actually contained, I can't remember. One thing was important: not to blend any more of it than prescribed, as the stuff absorbs water, and if used in excessive amounts it will absorb water from the surrounding air, which is obviously not good!

[checklist69]

This page sums things up:

http://www.chevron.com/products/prodserv/fuels/bulletin/aviationfuel/10_ag_composition.shtm

'69

[flyingfemme]

Always use isopropyl in the winter, in northern parts, in 300 and 400 series Cessnas.....not easy to get in the UK. I think Far North can supply.

[Jetset41]

H.Finn
Yes indeed Aeroshell 06A is used on cessna 421's.
The later 421's had a oil feed heated fuel divider in the fuel injection system which assisted with the fuel heating, but 06A could still be used, but I seem to remember 1% by volume, although this was a few years ago.

As for finding it hard to get, any Maintenance facility in the UK would normally stock atleast one 25 litre barrel, I know we have quite a lot at Biggin Hill.

You might find however that many fuel depots will not be able to supply in the quantaties that you require, and offer you a 25 litre\ 25 kgs metal drum of the stuff at rather high prices.

The main problem with this is that it IS highly flamable and you'll find that it only has a flash point of 10 degs C, so carrying it around because fuel farms don't stock it, is not really an option.

The answer is to plan ahead, if you know you need it make sure the airport you are off to, can get it from a friendly aircraft engineer.

Jetset41