Unload fuel, how?

pilotod

pilotod

Pre-takeoff checklist
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Some of the questions in the knowledge test have to do with how much fuel should be unloaded to make the plane meet the weight/balance criteria. Where would one drain the fuel in real life if that's the best decision to fix w/b?

Jamie
 
One could use the fuel sumps beneath the wings of many piston aircraft. or one could simply siphon it out of the tanks with some aquarium tubing, or a hose.
 
One would try and get a siphon pump and get it out of the tanks. Some FBOs have this capability, most don't. There's really no other way to get fuel out efficiently - the flow rate of the drains is really slow in the typical Cessna/Piper/Beech/Mooney
 
Take off and fly around the airport for a few hours to burn it away. Probably be faster than figuring out how to unload and store that much 100LL safely.

To be honest, there generally isn't a good way to safely unload the fuel. This is one of those areas that sounds simple at first but when you actually need to do it you'll have very few options.
 
If your airplane has fuel drains like these:
cca1550.JPG

Then you are lucky - you just turn the twist lock and let the fuel drain into a bucket - check with the FBO first to find where you can dispose of the fuel.

If have have sump drains where you have to insert a metal pin of some sort up into it, then it is a pain - may be easier/quicker to get an A&P to unscrew the drain completely.

If I needed to unload fuel and I had the twist drains and FBO had a way of disposing/re-using the fuel, then that is what I would do. If I had the other style, I'd probably do what Jesse suggests and go fly it off.
 
I think the question is more hypothetical than practical. Draining fuel from an aircraft is not something you'd want to do on a routine basis to fix your weight and balance. That said, I've drained the fuel tanks on my aircraft two or three times. It involves filling a series of 5 gallon jugs from the gascolator drain. It's boring and takes constant attention to do it safely.
 
Be VERY VERY careful no matter how you do it. It must be done outside and you need to be very careful about the static that will build up from the falling fuel. I personally know of two incidents which led to total losses (and in one case loss of other planes) from defueling incidents.
 
My W&B for tomorrow night is over gross with full fuel. Luckily, the instructor has an hour lesson before my flight, and I just requested them to not fill the tanks back up. Ill dip the tanks before the flight, and If i do have to drain, it should only be a couple gallons.

I've asked the draining question from CFIs and pilots I know personally, they all say "just use the sump drain" or a siphon hose. I've never seen it done, and only once have a seen a request for less than full tanks.

It tells me, more than a few pilots will fly over gross, and bank on burning off the excess in flight.
 
I've had to do it in real life, when an FBO incorrectly filled the tanks instead of giving me the 10gal/side I requested. Luckily they had a calibrated pump available and were able to defuel it through the openings at the top of the tank. It was a Lifeline Pilot flight, (and a rental airplane,) so flying around for a couple of hours really wasn't an option.

Edit: Just to clarify, I understood the flying around for a couple of hours to occur before taking the passengers aboard, so I would have been legal at all times.
 
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Also, remember that there is a ramp weight for start, taxi, and run up that uses some fuel..... Use that slightly higher number, maybe it would help.
 
We keep the CAP C182's below full all the time for this problem. Three guys and mission gear means we never have the tanks full. The newer T182T w/G1000 is a fat pig and carries less than the steam gauge bird.

On my 182 I can still unscrew a sump on one side, the right side. The other side now has the Eagle drain via STC after the left side bladder replacement, which is a hell of a lot nicer drain but is safety wired and not removable without a mechanic's sign off.

The other Eagle drain is on the shelf awaiting the right side bladder failure "someday", since they're sold in pairs only.

The bigger problem is where to put it. It won't all fit in my gas tug, which runs great on 100LL. Ha. :)
 
flyingron said:
Be VERY VERY careful no matter how you do it. It must be done outside and you need to be very careful about the static that will build up from the falling fuel. I personally know of two incidents which led to total losses (and in one case loss of other planes) from defueling incidents.
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what happened? They blew up?
 
pilotod said:
Of course, as the righteous student that's heresy.
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It's still heresy for this 40-year CFI and 9000+ hour ATP.;)

In any event, I've had FBO's pump out excess fuel (at their expense) when they overfueled my plane. They weren't happy about it, but there wasn't much they could say about it when the fueling instructions were in writing.
 
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I always use a chunk of garden hose or other large hose and gas cans to store the fuel for later. Use a clean hose piece, feed it into the filler until you are just holding the end, put your thumb over the end and pull out and down rapidly to get the fuel level and air bubble in the hose below that of the tank. Stick the end of the hose in the can as you remove your thumb and you'll be 30 lbs lighter in a few minutes.
 
Ron Levy said:
It's still heresy for this 40-year CFI and 9000+ hour ATP.;)

In any event, I've had FBO's pump out excess fuel (at their expense) when they overfueled my plane. They weren't happy about it, but there wasn't much they could say about it when the fueling instructions were in writing.
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That is why I typically observe the refueling or do it myself. I've had this happen too many times. It seems some FBO employees either can not read, or can not follow instructions. I know there are times when it is unavoidable but I always try to witness my refuel.
 
Ron Levy said:
In any event, I've had FBO's pump out excess fuel (at their expense) when they overfueled my plane. They weren't happy about it, but there wasn't much they could say about it when the fueling instructions were in writing.
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Same here. Should have put it in writing. But I had witnesses, asked twice and was very specific. Also very mad when it was filled all the way up.
 
Anthony said:
That is why I typically observe the refueling or do it myself. I've had this happen too many times. It seems some FBO employees either can not read, or can not follow instructions. I know there are times when it is unavoidable but I always try to witness my refuel.
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In my case I told the guy who came out and chocked my airplane, and 5 minutes later when the fuel truck pulled up I went out of the way to walk back to the plane and make sure the message had been passed on. And they still filled it all the way up.

^ I figured that was enough to make it not my responsibility. I discovered it was filled all the way up when I preflighted 2 days later.. of course I still assume responsibility for checking fuel myself before flying, but I don't feel I need to sit there and baby sit the guy. Most of them know what they are doing.. some don't, and i'll notice their mistakes on the preflight.
 
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The problem isn't removing it, the problem is figuring out where to put it. Not everyone has 30 gallons worth of gas cans laying around. Plus there are some safety risks in all this. Can't just put it back into the fuel truck.
gprellwitz said:
I've had to do it in real life, when an FBO incorrectly filled the tanks instead of giving me the 10gal/side I requested. Luckily they had a calibrated pump available and were able to defuel it through the openings at the top of the tank. It was a Lifeline Pilot flight, (and a rental airplane,) so flying around for a couple of hours really wasn't an option.
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Where did they put it?
 
dell30rb said:
Same here. Should have put it in writing. But I had witnesses, asked twice and was very specific. Also very mad when it was filled all the way up.
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No point in getting mad. Just get it fixed. Then put in the negative comment on AirNav when you get home.;)
 
jesse said:
The problem isn't removing it, the problem is figuring out where to put it. Not everyone has 30 gallons worth of gas cans laying around. Plus there are some safety risks in all this. Can't just put it back into the fuel truck.
Where did they put it?
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Lawn mowers, tugs, etc. Embry-Riddle's entire gardening machinery fleet now runs on 100LL drained from sumps on preflights. Savings helped pay the EPA fine from when they got caught dumping samples on the ramp (multiply 13 sumps/172 times 30 or 40 flights/day times like five hundred bucks per violation and the numbers add up). Turns out it was cheaper to comply with the Clean Water Act than to ignore it. How often does that happen?
 
Ron Levy said:
Turns out it was cheaper to comply with the Clean Water Act than to ignore it. How often does that happen?
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All the time, that's the point of attaching the fine to the crime. People won't do the right thing otherwise, they require threats and punishment.
 
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pilotod said:
Some of the questions in the knowledge test have to do with how much fuel should be unloaded to make the plane meet the weight/balance criteria. Where would one drain the fuel in real life if that's the best decision to fix w/b?

Jamie
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The morning of my PPL Checkride, I had the truck come out and told him to fill it to the tabs. He filled it all the way up, which put my W&B out of wack (and I was pretty sure I had to go over W&B with the DPE), so I called the FBO and they stuck a bucket under the drain and removed the drain (each wing). I never got that fuel back in the plane, either. Expensive little mistake. My A&P has since given me an updated W&B profile for my 140 and I can now get full fuel and two people in the plane (with a little weight behind the rear seats).
 
John221us said:
My A&P has since given me an updated W&B profile for my 140 and I can now get full fuel and two people in the plane (with a little weight behind the rear seats).
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If you always just leave that weight there and it exists for balance reasons, you may consider seeing about using a lesser quantity of weight secured further aft in the empenage.
 
jesse said:
The problem isn't removing it, the problem is figuring out where to put it. Not everyone has 30 gallons worth of gas cans laying around. Plus there are some safety risks in all this. Can't just put it back into the fuel truck.
Where did they put it?
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The pump was attached to a 55gal drum, IIRC.
 
Ron Levy said:
No point in getting mad. Just get it fixed. Then put in the negative comment on AirNav when you get home.;)
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I didn't get mad, nor did I leave a negative comment on AirNav. Also, the FBO didn't charge me for the fuel I didn't order. Had they done so, neither of these first two statements would have been true!
 
gprellwitz said:
The pump was attached to a 55gal drum, IIRC.
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You were lucky. Most are not set up for this event. I guess the risk of contamination is too great to have 55 gal drums of 100LL sitting around, not to mention fire and environmental hazards. Plus, as others have said, you can't just put it back into the fuel truck or fuel storage tank.
 
Anthony said:
You were lucky. Most are not set up for this event. I guess the risk of contamination is too great to have 55 gal drums of 100LL sitting around, not to mention fire and environmental hazards. Plus, as others have said, you can't just put it back into the fuel truck or fuel storage tank.
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Most places have drums for defueling. I know I burned a lot of drained fuel in the 2 years I worked at Foley's. All the fuel that came out of planes was mine, mine mine mine all mine!:D
 
get a hose, put it in the tank and suck on it until you get the syphon effect. make sure to don't get it on your mouth and to pour the fuel in an approve anti static container. Bucket will not do. As they say, "three useless things in aviation: fuel left at the pump, altitude above you, and runway behind you". Leaving fuel behind is the classic first link in an accident chain.
 
cirrusmx said:
get a hose, put it in the tank and suck on it until you get the syphon effect. make sure to don't get it on your mouth
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Anyone else remember Jean Shepherd's tasting guide to automotive gasolines, based on syphoning gas out of other folks' cars during the Depression? "Sinclair had an amusing piquance, with an aftertaste redolent of industrial cleaning fluid..."
 
My PPL checkride, with a "standard" FAA person W&B was just inside the envelope for the pre-flight planing. When the DE showed up, I knew he was a little hefty. I asked about his weight and re-calculated, showed we were about 20 lbs over max. So I told him we'd have to drain some fuel, he agreed, and then said let's go fly (fuel never left the plane except thru the carb). C 152 and hot Texas summer, the old codger didn't care (many years ago). Also didn't make me do the engine out landing scenario. Was a strange day... not what I expected at all, but I was a young buck back then.

*Edit* To Un-hijack the thread, siphoning with clear tubing is the best quick way to get gallons out.
 
Several years ago I had an FBO overfuel me, and they just pumped the fuel back into their truck, and didn't charge me for the overage.

Probably too much liability to do that these days.
 
JimNtexas said:
Several years ago I had an FBO overfuel me, and they just pumped the fuel back into their truck, and didn't charge me for the overage.

Probably too much liability to do that these days.
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Pumping it back into their truck is a pretty horrible idea and opens up all kinds of risk and fuel contamination issues.
 
At the flight school we had a slip tank with a rotary hand pump. I had a filter on the pump and a check valve in parallel to that filter, rigged so that when the pump was cracked clockwise, it forced fuel through the filter and hose and into the airplane. Cranking counterclockwise sucked fuel out of the aircraft tank and through the check valve, bypassing the filter. It was always getting used to reduce fuel weight, and occasionally we'd hide the fuel system key so the students got a taste of the real North by having to pump fuel from that tank.

A private owner could use a fuel drum and pump. Even without the check valve it would work OK. It would just suck minor solid contaminants from the filter back into the drum, where they came from in the first place. Water would stay in the filter's bottom.

Attach a ground wire to the drum, too.

Dan
 
jesse said:
Pumping it back into their truck is a pretty horrible idea and opens up all kinds of risk and fuel contamination issues.
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Not really Jesse, they will sample the fuel being removed.
 
cirrusmx said:
get a hose, put it in the tank and suck on it until you get the syphon effect. make sure to don't get it on your mouth and to pour the fuel in an approve anti static container. Bucket will not do. As they say, "three useless things in aviation: fuel left at the pump, altitude above you, and runway behind you". Leaving fuel behind is the classic first link in an accident chain.
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You've probably never heard of a "jiggle Syphon"

http://www.ebay.com/itm/Jiggle-Syph...ols_Equipment&hash=item336f711088#ht_2394wt_1
 
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Ron Levy said:
Anyone else remember Jean Shepherd's tasting guide to automotive gasolines, based on syphoning gas out of other folks' cars during the Depression? "Sinclair had an amusing piquance, with an aftertaste redolent of industrial cleaning fluid..."
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No, but I do remember my Dad carrying a hose and calling it an Arkansas credit card.
 
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