Water in the fuel

[Bryon]

Just a question to clear my mind. Every time I do a preflight on an aircraft I check the fuel for contamination by water etc. What happens or what am I supposed to do if I find some water in the fuel sample? Do I drain the tanks and system completely or do I just keep taking samples until the sample is clear?

 

 

[Tomo]

Water will go to the bottom, so if you discover water - just keep draining it till its gone. The drain is usually on the lowest part of the tank, so that is where all the water will be if it has any.

 

Same if you come across little dirt particles or something, just keep doing it till it is all clear.

 

:thumb_up:

 

 

[dazza 38]

Just as Tomo said.

 

 

[storchy neil]

next time that you buy fuel before putting in plane check that there is no ethenol in the fuel

 

as water and ethenol mix condensation in the tank will mix with ethenol neil

 

 

[Guest Maj Millard]

All the above is good except for the follow rare events, both of which I have encountered during my GA flying/maintenance days.

 

1.You take a sample, look at it and it is completly clear with no water or crud at the bottom, you think great and dump it. WRONG....the whole sample is water !! The tank has a large quantity of water in it due heavy overnight rain, and a leaking fuel cap seal. Solution: always give your fuel samples the 'smell test'. The color should be an indication also. Clear sample...it's water. I have done this and taken at least three samples before I actually got fuel, in an on-line rental aircraft.

 

2. You get a clean fuel sample with no water bubble indication at the bottom, but the fuel is full of water !...how can that be ? The water has not 'settled', and has combined or suspended in the fuel. This can and does happen, and appears in the fuel like tiny Champangne bubbles. The presence of Ethonol now in some fuel contributes to this problem, as the ethonol combines with the water and takes it into suspension.

 

READ your fuel samples, don't just check them...and don't forget the smell test !...........................................

 

 

[Thx1137]

Doing a drain on a Sporty last week, the colour didn't look right but the smell was normal. I suspected it was because the fuel drain checker was brand new making the colour look lighter (not clear but a fair bit lighter) than what I am used to. I opted for a second drain (which was the same) and got a second opinion.

 

We decided it was ok, it did play on my mind a little until I had departed the circuit. I don't like things not being 100% consistent! :-)

 

 

[Guest Maj Millard]

Wise man thx1137..............................................................................:thumb_up:

 

 

[Bryon]

:thumb_up:Thanks everyone, that has settled my mind a bit

 

 

[Relfy]

I'd also have a look at your fuel filter also, just in case it has started to come through the lines. This would be more so for an aircraft used by others.

 

 

[Neville75]

I read somewhere to check for cows in your fuel....

 

Colour, Odour, Water, Sediment.

 

 

[Guest Maj Millard]

David, Other than performing the ol' rock and roll proceedure on 182s as required, you must also check and drain, the drain point under the belly. This is what got us in Batchelor with the loss of two lives and a good 182. Can't remember the capacity of the sump in the belly, but it is the low point and will quite readily fill with water. We suffered an instant and complete engine failure from full power just after takeoff. I am constantly amazed just how many new 182 pilots don't even know there is a drain point under the belly !!!.....................................................

 

 

[Guest Maj Millard]

We didn't have time for any expletives, from full noise to the big trees in about 3 seconds. We were fully loaded with 4 POB and full fuel. My lucky day......and Oh BTW, the sound of silence that day was deafening !!..................................

 

 

[Guest Maj Millard]

Yes if it had fireballed I wouldn't be here, we took a wing clean off , and we were covered in fresh Avgas. Like I say my lucky day !....for a few years after, every time I got a whiff of avgas, the old heart would go ballistic, but it's over 30 yrs ago now. Check those sump drains !!!

 

The crash was written up in the crash comic at the time, and I really should post it for educational purposes............................................................................

 

 

[skydog]

Fuel check after fill up

 

Whats everyone thoughts on doing a fuel check right after filling up?

 

Standard practise calls for this but as an instructor said to me once it is likely a waste of time as the water will be mixed and and not settled for quite a while?

 

Best to wait but for how long?:stirring pot:

 

 

[dazza 38]

Hi David and Skydog, IMO you are both right. I wait until the last minute to check the fuel, after refueling. I normaly fuel up, then carry out my pre-flight inspection, then wait along as i can before doing the fuel drain. If the a/c is already say half full or over, i will do a fuel drain before re-fueling and then after re-fueling.It does depend what particular a/c your are flying. (as previously explained by Mr Isaac). Some a/c the drain is only under the tanks. where as some a/c their is no drain under the tanks but is located in the lowest part of the fuel system, normaly near the fire wall. If you do a fuel drain, before re-fueling at least you can be satisfied that the fuel on board is clear of water, setiments etc.Re-fuelling can/will stir up/mix water in the fuel, unfortunately i dont know myself how long it takes to settle to the lower part of the tanks. That is why i leave it to the last possible minute. I hope this helps.

 

 

[Guest Dick Gower]

And before you drain it again Bryon, shake the wing around a bit because water can lie of the bottom of the tank and not flow towards the drain, particularly with bag tanks.

 

 

[motzartmerv]

I read an interesting rule in the cao's recently. It states that a sample of fuel should be added to a container which 'already' contains fresh fuel, so as to show a demarkation between any water and the fuel. I have to say I have never seen this done. But, it is the rule.

 

 

[facthunter]

testing fuel for contamination.

 

That is correct Merv. You can also use a test paste. (Colour change).

 

Contamination with diesel is a worry with piston aircraft. Not detected by any of the above methods.

 

Diesel or Avtur will lower the octane rating of the fuel and the engine destroys itself by detonating.

 

My view of doing fuel drains is that you can hardly ever do too many.

 

Do the tanks after fuelling and maybe the lower one every time you fly.

 

We used to leave all the Aero club planes tanks fULL after the days flying to reduce condensation. With some U/L's you cant carry full tanks and some heavy folks so that practice is not applicable. Nev

 

 

[eightyknots]

1.You take a sample, look at it and it is completly clear with no water or crud at the bottom, you think great and dump it. WRONG....the whole sample is water !! The tank has a large quantity of water in it due heavy overnight rain, and a leaking fuel cap seal. Solution: always give your fuel samples the 'smell test'. The color should be an indication also. Clear sample...it's water. I have done this and taken at least three samples before I actually got fuel, in an on-line rental aircraft.

Thanks for that Maj Millard! That's really useful safety advice that I had never thougt of before ...and that I have not been taught at flight school (at least, not yet).

 

 

[Guest davidh10]

I read an interesting rule in the cao's recently. It states that a sample of fuel should be added to a container which 'already' contains fresh fuel, so as to show a demarkation between any water and the fuel. I have to say I have never seen this done. But, it is the rule.

I read this somewhere (not sure whether it was CAOs or VFRG) not long after getting my pilot certificate and thought it made good sense as it both avoids missing a colour change or having all water in the sample.

 

For that reason I have been doing this every time I do a drain check. I check the fuel batch for Ethanol each time I fill my Jerry Cans. If I have a mixture of tested and untested cans, I mark the untested ones.

 

Just thinking through this as I write, I should swap to marking the "Tested" cans, as it is a positive indication,rather than the lack of a negative indication.

 

 

[Yenn]

I always do a sniff test to see if it is really avgas or just all water. Probably not the very best for health, but it is only once or twice a week.

 

 

[facthunter]

like It?

 

If you fly a lot, perhaps you should use opal fuel. (Not as addictive). Avgas is OK too.. Nev

 

 

[dazza 38]

If glad your still with us CFI, reminds me of a day at Skyfox flight training at Caloundra.When a mate of mine who held a CPL helicopter licence.He carried out a fuel drain on a Skyfox early morning, winter time, first flight of the day.It had taken about four full cups of water before the fuel sample was clear of water.