Water / Ice in fuel

[dwshimoda]

Given the current weather conditions, am I right in assuming that the best way of preventing ice forming in the tanks is to keep the tanks topped off when the aircraft is on the ground?

Have heard numerous stories of people checking for water, not finding any as it's frozen inside the tank, then defrosts during flight and causes engine stoppage. I'm planning a flight early one morning this week and want to make sure there is no chance of that happening.

Also, what other preventative measures do people take with the weather currently being Siberian? (The plane is obviously not hangered)

DW

[maggioneato]

The joys of winter flying and an aircraft parked outside. I don't scrape off frost, if it's that bad I fly another day. If covered in frost and sunny, that's a different matter, turn into sun, brick under nosewheel, it soon melts. Don't see that you can do much about the water in fuel bit, other than be aware if it's an aircraft that often has water in the fuel when preflighting like the one I used to fly, it could be frozen. The one I'm flying at the moment I have never drained water from it's 13 drainplugs, but that doesn't mean it will always be that way. I suppose the only sure way is not to fly in these conditions, but that's a bit drastic.

[mazzy1026]

This sounds daft, but when I do the pre-flight checks, I give the wings a 'waggle' - not only to check the undercarriage structure etc, but it also means that any water that may have settled in the tank, is more likely to sink to the bottom, so that when you drain fuel for the check, the water will come out. I fly a Tommy, so this will differ on type.

:ok:

[Three Blades]

keeping the tanks topped up reduces the amount of air within them.
This in turn, reduces the amount of water vapour that could condense out.
So a full tank is better than an empty one.
(Although I have not had problems with aircraft, I did suffer water contamination in the diesel of a tractor that I left with 1/4 full tanks over one winter !)

[bookworm]

Given the current weather conditions, am I right in assuming that the best way of preventing ice forming in the tanks is to keep the tanks topped off when the aircraft is on the ground?

While condensation (and therefore head-space) may be an issue in the tropics, I think 95% of water found in tanks in the UK comes in as rain through leaky filler caps. Thus your best way of avoiding it is to make sure that the filler caps are replaced if they fail to provide a good seal.

[dwshimoda]

Mazzy,

Not daft - I also do that. I fly a 172, and have never drained more than a couple of drops of water out. It's just at the club the other day someone was speculating on the reason for an engine failure in a recent accident, and suggested that if you did have water in the tanks, and it froze over night, you could drain the tanks, set off happy in the knoweldge you've got all the water out of the system, and then run into trouble as the ice melts...

I'll check the filler cap seals as suggested, and keep the tanks topped off each night.

DW

[TheKentishFledgling]

The one I'm flying at the moment I have never drained water from it's 13 drainplugs

13?! What kind of aircraft is that???

tKF

[Fuji Abound]

Just allow the flame of a burning candle to warm up the area around the fuel drain - does a marvelleous job of melting any ice that might have formed in the tanks.

[John Farley]

A couple of thoughts

Before doing anything else how about trying to measure the temperature of the lower skin of the fuel tanks to try and get a worst case estimate of the fuel temp inside?

How about rocking the wings as violently as possible (as suggested) to try and mix the cold bottom layers with the warmer upper layers then 'dipping' its mixed temperature? If the fuel temp is (say) less than 3deg you might decide to have a cup of coffee.

[High Wing Drifter]

Just allow the flame of a burning candle to warm up the area around the fuel drain - does a marvelleous job of melting any ice that might have formed in the tanks.
Woof!

Where's Fuji?

Dunno, he was there a moment ago.

[John Farley]

I also like Fuji's idea of warming up the drain area. Not sure about the source of heat though. Gloves, very hot water and a sponge might help.

[charlie-india-mike]

TkF


We have an aircraft that has 15 drain points made by Mr Cessna.

C-I-M

[maggioneato]

tKF. Tthe one with 13 drain points is also made by Mr Cessna. 5 under each wing, and three you have to grovel on the floor under the engine.
CIM, I thought 13 was OTT.

[foxmoth]

If it is water that has settled in the fuel it should be at the bottom (in the drains) anyway and if it has frozen you will probably then find you cannot get anything out of the drains (if you waggle the wings you are as likely to distribute any water through the fuel as get it to go in the drains) - if this happens you need to worry - otherwise you are probably OK.:uhoh:

[Yorks.ppl]

Foxmouth has explained it the way I always understood it. If the water is frozen nothing comes out, if its not it will drain off as normal.

[CptWood]

I agree, if there is water in the tanks it will finds its way to the bottom quicker than it can freeze anywhere else. Thus when it actually gets cold enough to freeze it will be on the bottom of the tank blocking the outlet to the drain points. Still with that in mind you should still perform an extensive fuel pre-flight with the suggestions put forward (rocking wings etc). Remember its better to be on the ground wishing you were in the air, then in the air wishing you were on the ground :)
Happy Flying

[Confabulous]

Does any GA aircraft use fuel heaters, apart from turboprops? Might be an easy fix... or maybe not! Perhaps a steel rod/tube at the bottom of the tank connected to the exhaust? Then again that would only work when the engine is running... maybe connect it to the battery?

[Cusco]

Many years ago my Dad had a little paraffin burner which he left under the engine of his car overnight.

It was about 12 inches across and pretty flat, with a fine mesh grill over the top a la Davy miners lamp.

Held enough paraffin for 2 overnight burns IIRC.

Dunno if they still exist: maybe if not they could be re-invented: certainly would provide risk free warming of the fuel cock.

Safe flying