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John Baker

John Baker

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John Baker
From the FAA. Water in your fuel system.

John
 

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And why exactly did they feel they needed to issue an SAIB for this? This problem is not exactly new nor has it recently become more critical.

Like all government agencies, they are just issuing notices to justify their job.
 
I learned something new: checking fuel for water or contaminants between flights even if the fuel system has not been opened. Previously, I would check fuel prior to my flight, land somewhere, shut down parked airplane, go inside to eat, conduct walkaround, then fly home.
 
airguy said:
And why exactly did they feel they needed to issue an SAIB for this? This problem is not exactly new nor has it recently become more critical.

Like all government agencies, they are just issuing notices to justify their job.
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That was my thought exactly. Everything in there was stuff that I learned as a student pilot on my first lesson on how to pre-flight an airplane.

The allude to a problem with Cessna aircraft, but then they don't really go into specifics that might help those who haven't experienced some of the different configurations like bladder tanks in the 70's model 182s and 177s that can develop wrinkles and trap watter. Seems like that kind of stuff would be more worthy of a SAIB.
 
Jaybird180 said:
I learned something new: checking fuel for water or contaminants between flights even if the fuel system has not been opened. Previously, I would check fuel prior to my flight, land somewhere, shut down parked airplane, go inside to eat, conduct walkaround, then fly home.
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If that's all you do, then you are generally ok.

The real problem that they are alluding to is when you fly an airplane and then park it say overnight and don't fill it up. Trapped water can settle to the bottom or water vapor can condense overnight and show up the next day. If you fly it someplace and it sits on the ramp for an hour, any water will likely still be suspended from sloshing around in flight, and unless it rains while you are on the ground, no new water is getting in.
 
Fearless Tower said:
If that's all you do, then you are generally ok.

The real problem that they are alluding to is when you fly an airplane and then park it say overnight and don't fill it up. Trapped water can settle to the bottom or water vapor can condense overnight and show up the next day. If you fly it someplace and it sits on the ramp for an hour, any water will likely still be suspended from sloshing around in flight, and unless it rains while you are on the ground, no new water is getting in.
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This is exactly the water I want to get out during preflight. I shake the airplane then allow it to settle before sumping for this reason. Water is more dense than fuel and should sump out. Unless I'm flying in visible moisture, (I hypothesize) there should be no new water (of any detectible amount) in the fuel system.
 
Jaybird180 said:
This is exactly the water I want to get out during preflight. I shake the airplane then allow it to settle before sumping for this reason. Water is more dense than fuel and should sump out. Unless I'm flying in visible moisture, (I hypothesize) there should be no new water (of any detectible amount) in the fuel system.
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Water can be suspended in fuel and not simply settle to the bottom in a matter of a few minutes.
 
We were taught that it settles 1 inch per hour once the tank has been sloshed around and agitated during fueling.

I used to fly a 210 that would trap massive amounts of water and sediment. It would take many repetitive shaking of the wings to get all of the water and sediment out.
 
LearDriver said:
We were taught that it settles 1 inch per hour once the tank has been sloshed around and agitated during fueling.

I used to fly a 210 that would trap massive amounts of water and sediment. It would take many repetitive shaking of the wings to get all of the water and sediment out.
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Cessnas with bladder lined tanks are notorious for trapping water. The combination of bladder wrinkles and minimal wing dihedral makes it possible to have water settle out yet not reach the sumps without "vigorously" shaking the wings (which probably re-suspends some or all of the water). I guess this is a hidden advantage of low wing airplanes which typically don't have that problem due to the greater dihedral commonly employed for stability.
 
LearDriver said:
We were taught that it settles 1 inch per hour once the tank has been sloshed around and agitated during fueling.

I used to fly a 210 that would trap massive amounts of water and sediment. It would take many repetitive shaking of the wings to get all of the water and sediment out.
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Take a sample of fuel and add some water and then tell me us if it moves faster or slower than 1" per hour.

I tried this BTW, when I bought my GATS. I wanted to know if it worked as advertised.
 
Jaybird180 said:
Will it or will it not settle in a few minutes?
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Depends....if it is free water, then yes it will settle, but if it is suspended in the fuel, it will not necessarily settle quickly.

To be honest, I've never personally seen it in AVGAS, but in DFM (marine diesel) and JP5, we see water suspended where it doesn't easily settle quite often and we'll have to run it through the purifiers.

Just because it doesn't settle right away, doesn't mean that you can't detect it. That's why you look for 'clear and bright' in the samples
 
Jaybird180 said:
Unless I'm flying in visible moisture, (I hypothesize) there should be no new water (of any detectible amount) in the fuel system.
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Careful. With enough moisture in the ambient air and a night-time temperature drop, condensation can form inside any tank. Think "dew" on the grass in the early morning in humid climates with big temperature swings.

Generally our dry air here won't do it often, but some places, heavy dew on everything in sight in the morning is an almost year-round, daily occurrence.

Keeping the tanks full gives less cold surface area for this to happen on inside the tank and less water-laden humid air to feed the process.
 
If the airplane has been idle overnight, I will always check fuel due to the temp/dew point spread issue as noted.
 
Jaybird180 said:
Take a sample of fuel and add some water and then tell me us if it moves faster or slower than 1" per hour.

I tried this BTW, when I bought my GATS. I wanted to know if it worked as advertised.
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That's not really the same as suspended water. A large amount of water will simply sink. Sespended (or even a small amount of dissolved water) water takes a while to fall out. Water in suspension shouldn't be an issue for the engine though. You can adjust the mixture to compensate.
 
Jaybird180 said:
Take a sample of fuel and add some water and then tell me us if it moves faster or slower than 1" per hour.

I tried this BTW, when I bought my GATS. I wanted to know if it worked as advertised.
Click to expand...

Take your sample container, weigh it. Then take your fuel sample, weigh it. Then add your water, weigh it. Shake it up, let sit. Shake it up some more, let sit. Shake it up some more, let sit. Shake it up some more, wait 5 minutes, separate your water and weigh it. Let us know the results...
 
FWIW Before heading out to the rockys for the first time I took my plane up to 17odd thousand to confirm it's performance at altitude.

On the decent in clear air I ended up with water streaming back on the bottom of my wings in the location of the fuel tank. I'd suspect that just as much (or nearly so) water condenced in the tank too.
 
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