Water Contamination
Joined: Jul 2002
Posts: 833
Likes: 1
From: Canberra, Australia
I was told by a Shell refueller that it would not and that the syringe/capsule test was overkill for turbine helicopters. Not sure I'd stake my life on it though.
Could the suspended water form droplettes in the tank after a change in temp/atmospheric pressure?
Could the suspended water form droplettes in the tank after a change in temp/atmospheric pressure?
Joined: Jul 2003
Posts: 464
Likes: 2
From: UK
It is possible to get molecular suspension in fuel and if you go high enough and/or are flying in cold enough conditions it is possible for the water to begin to build as ice in the filters.
I was on a C-130 back in 1982 that suffered an engine failure and a partial loss of power on a second due to icing in the filters following molecular suspension.
I was on a C-130 back in 1982 that suffered an engine failure and a partial loss of power on a second due to icing in the filters following molecular suspension.
Joined: Sep 2000
Posts: 338
Likes: 0
From: UK
I'm more than surprised that a Shell refueller advised that the syringe/capsulre test is an overkill for turbine engines.
A positive test for water in suspension does not necessarily mean that engine problems will occur, but it warns that the concentration is sufficiently high to enable water to condense out of suspension should the conditions alter. i.e change in temp/pressure etc This could give rise to a sufficient amount of water in the fuel lines to cause power loss or complete shut down.
Leaving an aircraft overnight in conditions where daytime temps are in high 30degs plus and night temps drop substantially can cause such a problem.
Daily sump testing and checking fuel supplies before and after delivery are essential for longevity..........
A positive test for water in suspension does not necessarily mean that engine problems will occur, but it warns that the concentration is sufficiently high to enable water to condense out of suspension should the conditions alter. i.e change in temp/pressure etc This could give rise to a sufficient amount of water in the fuel lines to cause power loss or complete shut down.
Leaving an aircraft overnight in conditions where daytime temps are in high 30degs plus and night temps drop substantially can cause such a problem.
Daily sump testing and checking fuel supplies before and after delivery are essential for longevity..........
Tightgit
Joined: Dec 2003
Posts: 806
Likes: 7
From: The artist formerly known as john du'pruyting
Whether you think it is suitable for use or not.
CAP 748 Chapter 4, page 2 states that fuel should be considered unfit for use in aircraft if a visual examination shows a positive reaction to a water finding paste,paper or chemical
CAP 748
Chuck it
CAP 748 Chapter 4, page 2 states that fuel should be considered unfit for use in aircraft if a visual examination shows a positive reaction to a water finding paste,paper or chemical
CAP 748
Chuck it
Avoid imitations
Joined: Nov 2000
Aviation Qualifications: ATPL
Posts: 15,110
Likes: 1,083
From: Wandering the FIR and cyberspace often at highly unsociable times
I can't imagine that very fine droplets of water would affect the actual engine, they would go straight through the relatively large fuel jets. I suppose a large proportion of suspended water must by definition cause a reduction in power output but I'm sure this would be an extreme case and would be visible to the naked eye.
However, suspended water MAY affect the contents gauge readings where capacitance type sensors are used, a gauge over-read would occur due to the water content.
I also understand that the presence of suspended water gives more of a storage problem because bacterial growths can occur in it.
However, suspended water MAY affect the contents gauge readings where capacitance type sensors are used, a gauge over-read would occur due to the water content.
I also understand that the presence of suspended water gives more of a storage problem because bacterial growths can occur in it.
Joined: Sep 2004
Posts: 80
Likes: 0
From: Back of Beyond
I would not start up without having the A/C tanks checked, also the tank farm and filters.
Probab;ly doesn't harm the engine as such, but does the FCU no good at alll, seen a few FCU changes due to contaminated fuel, some engines may have a higher tolerance than others, but daily checks is the only way to go.
Probab;ly doesn't harm the engine as such, but does the FCU no good at alll, seen a few FCU changes due to contaminated fuel, some engines may have a higher tolerance than others, but daily checks is the only way to go.
Joined: Nov 2004
Posts: 318
Likes: 0
From: North of Soton
As said earlier, the problem is mainly icing in filters and in controls ie FCU etc. However as also said earlier it can cause other problems internally in FCUs with regard to corrosion, especially on older mechanical systems.
I'm surprised the question was asked to be honest!
I'm surprised the question was asked to be honest!
Joined: Nov 2003
Posts: 441
Likes: 0
From: Tasmania and High Wollemi
water solubility in Jet A
the problem arises from the decreased solubility of water in Jet as the temp drops. Similar to loading too much sugar in a coffee or tea. It can only dissolve so much then precipitates out into visible water. As the fuel chills off in flight the water can be sufficiently cooled to cause precipitation. Can also happen in drums moved to a cold area after filling.
Water detecting paste ( green stuff that goes purple ) only works on water you can basically see and should only be used on avgas. Shell water detector or similar should always be used including on daily's
How much water can put the fire out in an Allison????????
Cheers
Water detecting paste ( green stuff that goes purple ) only works on water you can basically see and should only be used on avgas. Shell water detector or similar should always be used including on daily's
How much water can put the fire out in an Allison????????
Cheers
Thread Starter
Joined: Jul 1999
Posts: 3,931
Likes: 142
From: Warrington, UK
Re: Water Contamination
I'm surprised the question was asked to be honest!
Opinions seem to be divided, as always with these things. Ice particles are not a problem for us, we never get into really low temps, plus we have FSII added.
Joined: May 2005
Posts: 369
Likes: 0
From: Europe trying to enjoy retirement “YES”
Re: Water Contamination
Suspended water in fuel and operating in cold climates can it seems cause ice build up in airframe fuel filters as indicated above. I am not sure on the tec stuff? But I understand that parts per million water content (we used the Shell detector kit went green at 60 PPM) relating that to fuel burn rate and size if fuel/ice filter. The old 61 in cold climates could sometimes show a filter light if the filter was starting to block, this in cold weather was an indication of ice rather than fuel contamination (good fuel quality and handling procedures). As mentioned once the filter started to by-pass this allowed the ice crystals to reach the FCU inlet filter and this was when it became worrying as it could affect engine performance.
The later AS 332’s I think did away with ice filters and increased the size of the fuel filter bowl thus allowing a greater capacity for ice collection. Least that what the French chap on the refresher course seemed to imply. I am sure that the experts will be able to expand on the complicated theory stuff.
outhouse
The later AS 332’s I think did away with ice filters and increased the size of the fuel filter bowl thus allowing a greater capacity for ice collection. Least that what the French chap on the refresher course seemed to imply. I am sure that the experts will be able to expand on the complicated theory stuff.
outhouse
Joined: Apr 2003
Posts: 3,012
Likes: 1
From: USA
Re: Water Contamination
The TSO for fuel icing call for a horrendous amount of suspended moisture, and the screen areas are consequently very large, or heated with recirculated fuel as a result. While it is possible that for some helos with very cold environments and saturated fuel to get a fuel system icing problem, some dissolved water in fuel is no great concern, as long as there is no liquid water pumped in with the fuel.
