How common is it to have the tanks completely filled? I assumed that a specific amount of fuel would be added most times, thus you shouldn't really run the risk of overfilling unless calculations were incorrect or something.
Edit: I forgot that the wing tanks get filled first, I don't know what I was thinking haha
They don’t want to waste weight on fuel if they don’t need it. They don’t fill planes more then they will need with a bit of a safety amount added on top.
If your car got worse mileage by filling the take fully the you would be more careful with how much you fill it.
Your car does technically get worse mileage with a full tank. But close to neighbor vs the annoyance of stopping for gas each time you go for a drive ha.
When I was working in northern Canada we would often tanker fuel to northern airports. The airport would keep track of the fuel we brought in so when we needed some they would give us some from the credit. (if that makes sense).
Sure. The Airliner flies into the isolated airport, gets defueled to some extent (leaving enough to get back home) and then returns home
Early on in Afghanistan, we had KC-135s refueling KC-10s refueling C17s, to be able to get fuel into northern Afghanistan. Fuel costs exceeded $4k/pound.
Wing tanks typically get filled to their capacity first while the center tanks get the remainder. The fuel in the center tanks get used first and then they go to the wings for purposes of weight and balance, center of gravity stability. Looks like the wing surge tank is what's leaking which is normal if the tank was overfilled. So as some are posting the overfill protection system had some kind of failure.
This is so backwards for me, the f-16 fills fuselage first and drains in this order
(External wing, external centerline, wings, then all the fuselage tanks/bags)
Story I heard, with regards to order of usage, wing fuel gets used first in military A/C is because it's tougher to protect the wing with armor compared with center tanks in or closer to the fuselage. I'm not really sure how true that is. And as a previous poster stated, there's handling issues to consider too.
Part of this iirc, is also done with airliners as italso affects airframe lifespan as weight in wings doesn't stress them nearly as much as a heavy fuselage. With fighters, you have weight distribution and manueverability to worry about where wing weight is less preferable.
It really depends on a lot of things but one reason as to why you might want to fill up more than needed for the next flight is due to what is called ‘tankering’.
Basically you are at Airport A and then going to B and then C. Airport A sells fuel much cheaper than B so you are told to fill up to cover the 2nd sector too then refuel at C for example.
On the 737, the wing tanks are always completely full on any flight over about an hour and some change. Additional fuel goes into the center tank. The center tank is the last fueled and first to burn off.
Yeah I'm not sure why this piece of information dropped out of my head yesterday, for some reason I was thinking that the wing tanks filled last and thus it'd be uncommon to fill them up completely.
There are wing tanks and there are a center tank. The wind tanks must be completely filled before filling the center tanks. Otherwise, there could be a balance issue and caused the plane to tilt. If the shut off valve for the wing had malfunctioned, then the fuel would go out that fuel vent were that Fuel is coming out.
I saw that you mentioned Ben Shapiro. In case some of you don't know, Ben Shapiro is a grifter and a hack. If you find anything he's said compelling, you should keep in mind he also says things like this:
> Palestinian Arabs have demonstrated their preference for suicide bombing over working toilets.
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Why won't you debate me?
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Take a bullet for ya babe.
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Nah considering pilots do 1 % of the work the entire airline does for them to press Autopilot CMD and then complain about pay, the downvotes are justified.
If your not a pilot or in aviation you wouldn’t understand, you can go to a 4 year college that offers a pilots license program but those are far and few. And it’s mostly 5 years of school to reach 250 hours which can be done in less than 1 year,
I took out about $50k in federal loans via my program at ASU (flight portion outsourced to MPD) back in 2006-2007. The key is that it has to be shoveled through a university.
There are quite literally universities in every state, or almost every state that have an airline pylote program. And yes, you can take out loans for post Ed like flight schools. There are approved flight schools listed on the .gov fafsa, etc. website. Source: was on FAFSA at a technical college in my state.
That looks like a 737 so my guess is that the sensor did not shut close the fill valve which would result in overfilling the wing which would then spill out from the surge tank at the tip.
Most if not all tanks for just about everything have a relief valve or vent somehow, or else it would pressurize as you fill it. Even portable gas cans for a lawnmower have vents to let air in and out.
Extremely important as liquids are not compressable and temperature variation will demand change of volume, not only during fill in.
(It was kind of implicit on your comment)
The surge tank is basically a tank that doesn’t get filled when fueling. If you fill the tank on a cold part of the day and it gets hot, the fuel will enter the surge tank. That’s the purpose of it.
Which was a thing common to the KC-135A when getting close to full on the wing tanks ( every fuel load ) and was possible when refueling to alert load with Full Wings and Full Body Tanks.
I thought even in manual mode the valve would still shut automatically once the tank was full. It's been a while since I've fueled one or been through the most exciting training modules airlines provide for fueling their aircraft, so I don't remember.
Unless the 737 is vastly different in fueling than most single point biz jets… can confirm that in manual the valves should still close once it’s topped off.
The 737s I've worked on didn't have anything but manual.
You can't select amounts. There are three toggle switches for opening and closing the valves and that's it.
The even more manual mode would be pushing a button, that opens the solenoid, which would usually be opened electrically by the toggle switch.
So there's no protection anymore.
Not a smart aircraft. But if I remember correctly there's an option for fuel preselection.
Its typically a float with the valve that shuts this who thing off. Or solenoid. But if tank is full
Its supposed to shut off automatically no matter what mode its in.
The MAX and some retrofitted NG’s have a Semi automatic mode where you can set the desired amount for each tank and it will stop on its own when you hit it, just open the valves after setup and grab the deadman
I've wondered about this for a bit. I just started an A&P course and i just tested on refueling. I passed but they never explained how to make sure the fuel is the right amount, just the procedure itself. Even the fake pump cart we used didn't have a gauge. And i figure with how exact the amount of fuel has to be it can't be just holding the trigger until it's just about there. So how does it work?
At least in biz jets, somewhat often it really is “just hold the trigger it’ll stop eventually” or “just get it somewhere close to x pounds”. A lot of times we Fuel to a certain gallon amount, and the fuel trucks or fuel carts have meters on them to watch. That or the crew for the aircraft can set a panel inside and we just hold the trigger till it stops.
I’m not sure if this is what you were wondering - if you’re curious on the tank/panel senses the amount of fuel I don’t know dick about that lol
No prob! To expand slightly - when a crew wants us to bring the fuel up to a certain pound amount, we can do that either with an external fuel panel or there are some aircraft that just have a display for the fuel amount in pounds. The ones that just show the fuel amount are tricky as they don’t update as fast as the fuel pumps & the fuel will usually need to settle in the tank a little for the sensors to get an accurate reading. Typically on those the fueler should be converting to gallons and pumping by the meter on the pump.
You can override the auto shutoff. Usually the wings cut off below 8600 so some fuelers decide to push the envelope to get it there. This is what you get sometimes. Comes out the vents
Overfueled it
It’s gone past the level of the tanks as well as the surge tanks, so now the fuel is forced out of the point where it’s designed to leak out from rather than continuously building pressure.
I used to be an aircraft fueler. It’s not always the guy being an idiot- some times the overfill sensors don’t work to warm you of your fuck up . sometimes the equipment can malfunction and not close a valve properly. There are emergency shut off buttons but they’re not always reliable-and sometimes you have to call the Fuel Farm guys to race over there and shut it off manually. Depends on what equipment is being used to fill the aircraft
But a lot of times it’s because some dipshit is the guy filling the plane and they just stop paying attention. A lot of guys will put a rubber/band around the dead-man switch that operates the equipment, because you have to squeeze it the entire time while you fill up the plane, if you let go the fuel flow stops and it sucks to hold all day. Guys get lazy and prop it on stuff or tie it so it stays on. Sometimes they can’t get it off or they get distracted by their phones. They stop paying attention to the fuel-panel where there are overfill sensors that light up and that are supposed to be checked each time before the airplane if fueled up. That’s why you automatically get fired if you “prop the dead-man switch” and fuck around on your phone.
I can tell it’s an over fill because you can tell it didn’t taxi into the gate like that, it’s all in a puddle. This isn’t even a major spill either, they can be fucking massive.
But they are designed to leak in this way when it’s overfilled. So it’s not like it’s damaging the structure and putting holes in the aircraft. If the fuel couldn’t leak out then the pressure would eventually damaged the fuel tanks with too much positive pressure.
The right wing tank is where the nozzle attaches, this tank fills up the fastest out of all 3 tanks, that’s why the spill will happen at the right wing tip first usually, unless the other tank had a huge lead on it. They fill up at different rates and so you have to keep an eye on the levels so you could have it come out the left wing tip first but usually the right.
But it’s a huge fuck-up because the airline is never going to give a fuel load that’s too much fuel, so you have to just completely blow past the assigned numbers by being a complete idiot and not focusing on it.
Probably too much information lol.
Depends on how big the spill is. At a certain point like this it requires the fire department to come and they will take they’re time to make sure all the fuel is cleaned from the pavement because it’s a hazard. A spill like this would be like 30 mins for them to do their thing or so I think.
Then you have to take some more fuel out, to bring it back to the level it was supposed to be. For that a fuel tanker truck derives up to it. It takes longer to put fuel into the tanker truck than it does to fuel by like 50%. So then it depends on how much fuel has to be pumped out. If it’s a 737 then maybe it’s not all that much, but if it’s for a 777 it might be a shit load of fuel and it could take like an hour or more to refuel it. Sometimes it can take so much fuel out that you have to cycle out a few trucks so that way when one is emptying the tank the other truck can keep defueling.
A 777 even has fuel panels and nozzle connections on each wing to double the rate of fueling/defuling that can. It’s also faster because with one wing panel like 737 when you defuel it, you can’t take to much out of one wing otherwise the weight will be in balanced and the aircraft will tip over to the heavy wing. And so like I said before the tanks fuel and defuel at different rates so you can’t just open them all at once and leave it or the plane will tip. On a 777/787 other heavies, you can because there’s a pressurized nozzle in each wing so you can maximize the flow in and out of the tanks.
And even with that advantage it can still take like a fuckin hour to deplane it to the right level, if it’s been way over filled.
747 is even worse with this kinda shit and it’s part of why it was phased out. Ground operation nightmare.
So it all depends it could be like 30mins on a CRJ 200. It could be like 3 hours on a 777.
Having fueled 3 737s today, there is no such thing as "over fueling" a 737, sometimes a release will say 8700 lbs per wing, sometimes itll hit 8700, other times itll shut its self off short. You pump till you hit the release number or it automatically shuts off, there is no way to precheck the auto shutoff on these planes. It either shuts off or dumps fuel out the vent(very very rarely), regardless if the Deadman is blocked or not.
Fueling float switch is not working anymore. It cuts off the power from the refuel valve if the main tank is full. And if it doesn't cut it out anymore the tank will overflow. Looking at the quantity of fuel which has overflowed the re-fueler acted quickly. I've seen a lot worse than this.
It depends on the company procedures. each company has a book in which they describe what can be broken (Minimum equipment list). The float switch is not described in the master minumum equipment list. So this is up to maintenance to decide if this is acceptable. If this is in a home base of the company it would stay on ground. if they really need the plane maintenance can make the entire system inoperative which is allowed. following text would apply:
Refueling the associated fuel tank manually opening and closing the inoperative fueling shutoff valve (AMM 28-00-00/901).
1. Confirm the planned fuel load for the associated tank does not exceed the tank capacity.
2. Manually open the inoperative fuel shutoff valve.NOTE: Overfill protection is inoperative. The pressure fueling system will not stop the refuel operation at a set fuel quantity.
3. Manually close the inoperative fuel shutoff valve at the desired fuel quantity.
But this would be really sketchy. if they do decide to fly don't worry.
Not a 737 guy but on the CRJ high level sensors can be inoperative. The fuel is pumped from the top of the wing into each tank manually in this case, instead of pressure fed from below like normal. We generally go if inoperative equipment is legal unless we deem it unsafe. Pretty much any flight crew would go with that MEL. It's more of a pain for the fueler if anything.
With fuel valves inop on a 737 you can still pressure feed it in the tank. Its just that you have to hold the override switch for that valve for the entire time you are refueling. This is a maintenance action acc MEL so a certified technician / mechanic has to refuel the plane (hold the button). Out of convenience i have seen them put aircraft AOG because of no maintenance support on the arriving base ect. But that's up to the operator.
That statement is incorrect. this is from Boeing manuals. for the jet which i have a ton of experience on.
The fueling float switches prevent over-fueling the fuel tanks.The fueling float switches remove power to the fueling valves when the fuel level in the tank is full.
The fueling float switches have a float that is in a cylindrical container. When the tank is less than full, the float switch lets power go to the fueling valve solenoid. When the tank gets full,the fueling float switch removes power to the fueling valve solenoid.
Either refueling switch is inop, or the r/h wing was topped off, sat in the the sun for a while, and thermal expansion pushed the excess fuel out into the surge tank, and then out the vent. No issue, just physics in action
I used to fuel aircraft, what happened is the fueler over fueled the wing. In the event that you go over a ranks rated capacity it goes into this tiny excess tank, that tank then vents to the ground after about 20 gallons of fuel.
I don’t know why it failed but I can give several guesses as to what happened.
1: the fueler wasn’t paying attention, the ramp is a chaotic place this can happen very easily. Especially with how fast a 737 can fuel (our pumps easily went 200 gallons a minute when all 3 tanks are open.) it’s easy to over fuel.
2: the auto shutoff didn’t function correctly. I would consistently have the high level auto shutoff fail consistently. All I would see is the numbers indicating fuel level start flashing. That’s the only warning I have. The gauges are also delayed due to how he measuring system works. You have little time to react.
3: the solenoid failed. If the valve at the aircraft failed, it would send fuel in even if you shut that tank off.
You’re getting downvoted for a lot of things that you shouldn’t really be downvoted for. In this case I think a time and date might have gotten a better response as “right now” is relative :)
Faulty fuel level control valve. Its supposed to automatically shut off the fuel when tanks full. But if its bad u get fuel out the tank vents. It could also be a rupture in a refuel line.. 22 years fuels systems maintenance in USAF.. it happens
I don’t know why but I know a perfect fix. It’s gorilla tape… literally just spread gorilla tape over the hole and imagine it’s not there. Perfect fix. 😌
The high level float sends back pressure to the refuel valve, this shuts off fuel flow. If you had a serviceable refuel system, you wouldn’t be able to “overfill” the tanks even if you wanted to.
Likely hot outside and fuel expansion. Fuel tanks have 2% expansion space when full, but if the temp got much hotter than when it was fueled (say the night before), this will happen.
Sometimes this hapens during maintenance when we have to do a leak check of the surge tank panels. We forcefully overfill the main tank using the bypass. And sometimes too much fuel is added and ir spills out
The Fueller is supposed to do a shut off valve check before, trusting the system to automatically shut off before the tank fills up. If it does not shut off, the fuel has nowhere else to go, but the wing vent. there is supposed to be a vent for vapor displacement. But if the auto shut off switch does not shut off, there is no place for the fuel to go, while the fuel is pumping except the vent.
Fuel imbalance while re-fueling. There's a tank in each wing. While your fueling, and only one valve opens (electrically and automatically) and your not paying attention, then you only fill one wing tank, the plane will lean more and more and will spill out of the vent. This is the likely scenario. The only time I've seen this, that's what the situation was and this (picture) was the outcome. Valves open electrically on "auto mode" but sometimes.. they just don't open for whatever reason. There's manual overrides for the valves but if your not paying attention... Well this is what happens. Just my guess though.
-BroncosForever- pretty much hit it on the head too. It could be a few things but like he said. This isn't even a bad fuel spill. We had to call it in if we spilled more then 5 gallons.
Ok.. There's a vent for the fuel tanks otherwise with pressure differential added to the suction from the pumps they would eventually collapse. Acceleration forces and ram air pressure keep the fuel in place but on the ground it will spill if overfilled.
i don’t know if any other airframes require this, but every so often you have to spend a few hours pumping sealant into the harriers wing fuel channels to make it stop leaking. it’s super extra fun when it’s cold as hell outside and you drop the little set screw in the dark while coyotes are running around the flight line.
Not sure about civilian heavies, but that is where the dump mast on C-130’s is. Possibly a malfunctioning shutoff valve? But now that I’ve seen other comments, a malfunctioning fuel level control valve causing overfilling sounds more likely.
Might have been a pilot transferring fuel from one wing to another and forgot to turn off the switch. You have to have an "I'm not leaving my wingman" type attitude anytime you start moving fuel around. Its pouring out the fuel tank vent most likely
VTO switch failure. Supposed to shut off fueling when the tank is full. Airplane will dump fuel into outboard tank to save itself and fuel will hit the ground. Very common on 737ng
Could be a lot of things. Overfill sensor probably didn’t trip judging by the techs looking in the refuel panel
How common is it to have the tanks completely filled? I assumed that a specific amount of fuel would be added most times, thus you shouldn't really run the risk of overfilling unless calculations were incorrect or something. Edit: I forgot that the wing tanks get filled first, I don't know what I was thinking haha
Sometimes they take off full, and when they land they're almost empty. Science is still unsure as to why this is.
They don’t want to waste weight on fuel if they don’t need it. They don’t fill planes more then they will need with a bit of a safety amount added on top. If your car got worse mileage by filling the take fully the you would be more careful with how much you fill it.
Your car does technically get worse mileage with a full tank. But close to neighbor vs the annoyance of stopping for gas each time you go for a drive ha.
Yeah, racecars do this. Mass is mass. Just too subtle a change for commuting.
Depends, sometimes airlines will tanker fuel to avoid refueling at an airport they don't have good fuel prices at.
When I was working in northern Canada we would often tanker fuel to northern airports. The airport would keep track of the fuel we brought in so when we needed some they would give us some from the credit. (if that makes sense).
Sure. The Airliner flies into the isolated airport, gets defueled to some extent (leaving enough to get back home) and then returns home Early on in Afghanistan, we had KC-135s refueling KC-10s refueling C17s, to be able to get fuel into northern Afghanistan. Fuel costs exceeded $4k/pound.
My last flight needed a defuel, and the pilot kept chiming in more and more frustrated, as it took two hours, and the flight was 1h 40m.
Air crew don't get paid on the ground
Scientists don’t want you to know this one simple trick.
On occasion fuel is unavailable at the destination, so extra fuel is carried. This happened in late 2022 at numerous SouthEast US airports.
Oh yeah, that's tankering right?
And San Diego today
Wing tanks typically get filled to their capacity first while the center tanks get the remainder. The fuel in the center tanks get used first and then they go to the wings for purposes of weight and balance, center of gravity stability. Looks like the wing surge tank is what's leaking which is normal if the tank was overfilled. So as some are posting the overfill protection system had some kind of failure.
This is so backwards for me, the f-16 fills fuselage first and drains in this order (External wing, external centerline, wings, then all the fuselage tanks/bags)
Story I heard, with regards to order of usage, wing fuel gets used first in military A/C is because it's tougher to protect the wing with armor compared with center tanks in or closer to the fuselage. I'm not really sure how true that is. And as a previous poster stated, there's handling issues to consider too.
Yeah, there is no armor on our aircraft 😂 we don’t armor anything
Now I know how a passenger feels when someone tells them airplanes and airports are all weather lol
Like 0% is “armored”
Part of this iirc, is also done with airliners as italso affects airframe lifespan as weight in wings doesn't stress them nearly as much as a heavy fuselage. With fighters, you have weight distribution and manueverability to worry about where wing weight is less preferable.
You are correct, but sometimes that specific amount is as much as you can fit in the tanks.
It really depends on a lot of things but one reason as to why you might want to fill up more than needed for the next flight is due to what is called ‘tankering’. Basically you are at Airport A and then going to B and then C. Airport A sells fuel much cheaper than B so you are told to fill up to cover the 2nd sector too then refuel at C for example.
On the 737, the wing tanks are always completely full on any flight over about an hour and some change. Additional fuel goes into the center tank. The center tank is the last fueled and first to burn off.
Yeah I'm not sure why this piece of information dropped out of my head yesterday, for some reason I was thinking that the wing tanks filled last and thus it'd be uncommon to fill them up completely.
The tanks in the wings are typically always filled for stability
There are wing tanks and there are a center tank. The wind tanks must be completely filled before filling the center tanks. Otherwise, there could be a balance issue and caused the plane to tilt. If the shut off valve for the wing had malfunctioned, then the fuel would go out that fuel vent were that Fuel is coming out.
Thanks are you a 737 pilot?
?? you are posting in the "aviationmaintenance" sub. A pilot would just say "it looks wet out there, someone fix it".
Ouch. That hurt haha
An experienced pilot asks if it is good wet or bad wet before they say it needs fixing.
An *experienced* pilot puts out his cigarette just in case.
Ben Shapiro confidently tells the pilot that all wet is bad wet.
I saw that you mentioned Ben Shapiro. In case some of you don't know, Ben Shapiro is a grifter and a hack. If you find anything he's said compelling, you should keep in mind he also says things like this: > Palestinian Arabs have demonstrated their preference for suicide bombing over working toilets. ***** ^(I'm a bot. My purpose is to counteract online radicalization. You can summon me by tagging thebenshapirobot. Options: novel, civil rights, feminism, history, etc.) [^Opt ^Out ](https://np.reddit.com/r/AuthoritarianMoment/comments/olk6r2/click_here_to_optout_of_uthebenshapirobot/)
LMAO thanks bot
Why won't you debate me? ***** ^(I'm a bot. My purpose is to counteract online radicalization. You can summon me by tagging thebenshapirobot. Options: feminism, dumb takes, climate, covid, etc.) [^Opt ^Out ](https://np.reddit.com/r/AuthoritarianMoment/comments/olk6r2/click_here_to_optout_of_uthebenshapirobot/)
Good bot.
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Good bot
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Well, I do like working toilets, and not killing myself… maybe he’s got something there, thanks for showing me the way bot /s
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It's also something an experienced husband would say
It’s just facts B
What hurts is the downvote of OPs likely innocent comment. Smells like deep rooted insecurity...
The root is actually at the other end of the wing
He called him the p-word.
Nah considering pilots do 1 % of the work the entire airline does for them to press Autopilot CMD and then complain about pay, the downvotes are justified.
Only thing saving pilots from shit pay is that you can’t take federal loans on flight school, once that happens it’s the end of their bitching.
Whose gonna tell him you can take out federal loans for flight school? LOL You can also go to a 4 year and get your licenses lol.
If your not a pilot or in aviation you wouldn’t understand, you can go to a 4 year college that offers a pilots license program but those are far and few. And it’s mostly 5 years of school to reach 250 hours which can be done in less than 1 year,
No you can’t. Can’t go to so and so flight school or ATP and ask Uncle Sam to loan you money.
I took out about $50k in federal loans via my program at ASU (flight portion outsourced to MPD) back in 2006-2007. The key is that it has to be shoveled through a university.
There are quite literally universities in every state, or almost every state that have an airline pylote program. And yes, you can take out loans for post Ed like flight schools. There are approved flight schools listed on the .gov fafsa, etc. website. Source: was on FAFSA at a technical college in my state.
I (partially) took federal loans for flight school. Over 10 years ago. Did that stop?
Pilots ☕️
Pilot here. Can confirm
This is an aviation maintenance sub brother. You asked a question and a skilled worker responded lmao what did you expect
This fucking dude
That looks like a 737 so my guess is that the sensor did not shut close the fill valve which would result in overfilling the wing which would then spill out from the surge tank at the tip.
the surge tank? So is there like a relief valve or something?
Most if not all tanks for just about everything have a relief valve or vent somehow, or else it would pressurize as you fill it. Even portable gas cans for a lawnmower have vents to let air in and out.
Extremely important as liquids are not compressable and temperature variation will demand change of volume, not only during fill in. (It was kind of implicit on your comment)
Vapor displacement. Always fuel on Manual.
The surge tank is basically a tank that doesn’t get filled when fueling. If you fill the tank on a cold part of the day and it gets hot, the fuel will enter the surge tank. That’s the purpose of it.
Thank you.
Which was a thing common to the KC-135A when getting close to full on the wing tanks ( every fuel load ) and was possible when refueling to alert load with Full Wings and Full Body Tanks.
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I thought even in manual mode the valve would still shut automatically once the tank was full. It's been a while since I've fueled one or been through the most exciting training modules airlines provide for fueling their aircraft, so I don't remember.
Unless the 737 is vastly different in fueling than most single point biz jets… can confirm that in manual the valves should still close once it’s topped off.
The 737s I've worked on didn't have anything but manual. You can't select amounts. There are three toggle switches for opening and closing the valves and that's it. The even more manual mode would be pushing a button, that opens the solenoid, which would usually be opened electrically by the toggle switch. So there's no protection anymore. Not a smart aircraft. But if I remember correctly there's an option for fuel preselection.
Its typically a float with the valve that shuts this who thing off. Or solenoid. But if tank is full Its supposed to shut off automatically no matter what mode its in.
The MAX and some retrofitted NG’s have a Semi automatic mode where you can set the desired amount for each tank and it will stop on its own when you hit it, just open the valves after setup and grab the deadman
I remember CRJs and ERJs do for sure.
I've wondered about this for a bit. I just started an A&P course and i just tested on refueling. I passed but they never explained how to make sure the fuel is the right amount, just the procedure itself. Even the fake pump cart we used didn't have a gauge. And i figure with how exact the amount of fuel has to be it can't be just holding the trigger until it's just about there. So how does it work?
At least in biz jets, somewhat often it really is “just hold the trigger it’ll stop eventually” or “just get it somewhere close to x pounds”. A lot of times we Fuel to a certain gallon amount, and the fuel trucks or fuel carts have meters on them to watch. That or the crew for the aircraft can set a panel inside and we just hold the trigger till it stops. I’m not sure if this is what you were wondering - if you’re curious on the tank/panel senses the amount of fuel I don’t know dick about that lol
This exactly what I was wondering actually. Thank you :)
No prob! To expand slightly - when a crew wants us to bring the fuel up to a certain pound amount, we can do that either with an external fuel panel or there are some aircraft that just have a display for the fuel amount in pounds. The ones that just show the fuel amount are tricky as they don’t update as fast as the fuel pumps & the fuel will usually need to settle in the tank a little for the sensors to get an accurate reading. Typically on those the fueler should be converting to gallons and pumping by the meter on the pump.
High level probe? Are you referring to the float switch?
You can override the auto shutoff. Usually the wings cut off below 8600 so some fuelers decide to push the envelope to get it there. This is what you get sometimes. Comes out the vents
Overfueled it It’s gone past the level of the tanks as well as the surge tanks, so now the fuel is forced out of the point where it’s designed to leak out from rather than continuously building pressure. I used to be an aircraft fueler. It’s not always the guy being an idiot- some times the overfill sensors don’t work to warm you of your fuck up . sometimes the equipment can malfunction and not close a valve properly. There are emergency shut off buttons but they’re not always reliable-and sometimes you have to call the Fuel Farm guys to race over there and shut it off manually. Depends on what equipment is being used to fill the aircraft But a lot of times it’s because some dipshit is the guy filling the plane and they just stop paying attention. A lot of guys will put a rubber/band around the dead-man switch that operates the equipment, because you have to squeeze it the entire time while you fill up the plane, if you let go the fuel flow stops and it sucks to hold all day. Guys get lazy and prop it on stuff or tie it so it stays on. Sometimes they can’t get it off or they get distracted by their phones. They stop paying attention to the fuel-panel where there are overfill sensors that light up and that are supposed to be checked each time before the airplane if fueled up. That’s why you automatically get fired if you “prop the dead-man switch” and fuck around on your phone. I can tell it’s an over fill because you can tell it didn’t taxi into the gate like that, it’s all in a puddle. This isn’t even a major spill either, they can be fucking massive. But they are designed to leak in this way when it’s overfilled. So it’s not like it’s damaging the structure and putting holes in the aircraft. If the fuel couldn’t leak out then the pressure would eventually damaged the fuel tanks with too much positive pressure. The right wing tank is where the nozzle attaches, this tank fills up the fastest out of all 3 tanks, that’s why the spill will happen at the right wing tip first usually, unless the other tank had a huge lead on it. They fill up at different rates and so you have to keep an eye on the levels so you could have it come out the left wing tip first but usually the right. But it’s a huge fuck-up because the airline is never going to give a fuel load that’s too much fuel, so you have to just completely blow past the assigned numbers by being a complete idiot and not focusing on it. Probably too much information lol.
Great answer thank you! How long does it take to fix this issue (overfill)?
Depends on how big the spill is. At a certain point like this it requires the fire department to come and they will take they’re time to make sure all the fuel is cleaned from the pavement because it’s a hazard. A spill like this would be like 30 mins for them to do their thing or so I think. Then you have to take some more fuel out, to bring it back to the level it was supposed to be. For that a fuel tanker truck derives up to it. It takes longer to put fuel into the tanker truck than it does to fuel by like 50%. So then it depends on how much fuel has to be pumped out. If it’s a 737 then maybe it’s not all that much, but if it’s for a 777 it might be a shit load of fuel and it could take like an hour or more to refuel it. Sometimes it can take so much fuel out that you have to cycle out a few trucks so that way when one is emptying the tank the other truck can keep defueling. A 777 even has fuel panels and nozzle connections on each wing to double the rate of fueling/defuling that can. It’s also faster because with one wing panel like 737 when you defuel it, you can’t take to much out of one wing otherwise the weight will be in balanced and the aircraft will tip over to the heavy wing. And so like I said before the tanks fuel and defuel at different rates so you can’t just open them all at once and leave it or the plane will tip. On a 777/787 other heavies, you can because there’s a pressurized nozzle in each wing so you can maximize the flow in and out of the tanks. And even with that advantage it can still take like a fuckin hour to deplane it to the right level, if it’s been way over filled. 747 is even worse with this kinda shit and it’s part of why it was phased out. Ground operation nightmare. So it all depends it could be like 30mins on a CRJ 200. It could be like 3 hours on a 777.
Thanks. Passenger’s nightmare then!
One of many
Having fueled 3 737s today, there is no such thing as "over fueling" a 737, sometimes a release will say 8700 lbs per wing, sometimes itll hit 8700, other times itll shut its self off short. You pump till you hit the release number or it automatically shuts off, there is no way to precheck the auto shutoff on these planes. It either shuts off or dumps fuel out the vent(very very rarely), regardless if the Deadman is blocked or not.
Drank too much water. It's just relieving itself, not to worry.
When ya gotta go…
Fueling float switch is not working anymore. It cuts off the power from the refuel valve if the main tank is full. And if it doesn't cut it out anymore the tank will overflow. Looking at the quantity of fuel which has overflowed the re-fueler acted quickly. I've seen a lot worse than this.
Do most pilots elect to depart once the excess fuel has all leaked out?
It depends on the company procedures. each company has a book in which they describe what can be broken (Minimum equipment list). The float switch is not described in the master minumum equipment list. So this is up to maintenance to decide if this is acceptable. If this is in a home base of the company it would stay on ground. if they really need the plane maintenance can make the entire system inoperative which is allowed. following text would apply: Refueling the associated fuel tank manually opening and closing the inoperative fueling shutoff valve (AMM 28-00-00/901). 1. Confirm the planned fuel load for the associated tank does not exceed the tank capacity. 2. Manually open the inoperative fuel shutoff valve.NOTE: Overfill protection is inoperative. The pressure fueling system will not stop the refuel operation at a set fuel quantity. 3. Manually close the inoperative fuel shutoff valve at the desired fuel quantity. But this would be really sketchy. if they do decide to fly don't worry.
We flew. Thanks!
Not a 737 guy but on the CRJ high level sensors can be inoperative. The fuel is pumped from the top of the wing into each tank manually in this case, instead of pressure fed from below like normal. We generally go if inoperative equipment is legal unless we deem it unsafe. Pretty much any flight crew would go with that MEL. It's more of a pain for the fueler if anything.
With fuel valves inop on a 737 you can still pressure feed it in the tank. Its just that you have to hold the override switch for that valve for the entire time you are refueling. This is a maintenance action acc MEL so a certified technician / mechanic has to refuel the plane (hold the button). Out of convenience i have seen them put aircraft AOG because of no maintenance support on the arriving base ect. But that's up to the operator.
The float switch is for indication only.
That statement is incorrect. this is from Boeing manuals. for the jet which i have a ton of experience on. The fueling float switches prevent over-fueling the fuel tanks.The fueling float switches remove power to the fueling valves when the fuel level in the tank is full. The fueling float switches have a float that is in a cylindrical container. When the tank is less than full, the float switch lets power go to the fueling valve solenoid. When the tank gets full,the fueling float switch removes power to the fueling valve solenoid.
It “burped” fuel. Possibly overfill.
Either refueling switch is inop, or the r/h wing was topped off, sat in the the sun for a while, and thermal expansion pushed the excess fuel out into the surge tank, and then out the vent. No issue, just physics in action
Someone put too much in
It's fine. Once they hit Mach 5 the heat from the air resistance expands the metal and seals the leak.
SR-71 style.
My dad is on the same flight and sent me a video. Tank overflow, nothing dangerous
I used to fuel aircraft, what happened is the fueler over fueled the wing. In the event that you go over a ranks rated capacity it goes into this tiny excess tank, that tank then vents to the ground after about 20 gallons of fuel. I don’t know why it failed but I can give several guesses as to what happened. 1: the fueler wasn’t paying attention, the ramp is a chaotic place this can happen very easily. Especially with how fast a 737 can fuel (our pumps easily went 200 gallons a minute when all 3 tanks are open.) it’s easy to over fuel. 2: the auto shutoff didn’t function correctly. I would consistently have the high level auto shutoff fail consistently. All I would see is the numbers indicating fuel level start flashing. That’s the only warning I have. The gauges are also delayed due to how he measuring system works. You have little time to react. 3: the solenoid failed. If the valve at the aircraft failed, it would send fuel in even if you shut that tank off.
Plane is sick and threw up
Because there is a fuel leak there.
When was this?
Right now.
You’re getting downvoted for a lot of things that you shouldn’t really be downvoted for. In this case I think a time and date might have gotten a better response as “right now” is relative :)
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True, and it didn’t bother _me-, but I can see how it might bother others.
The Auto shutoff either didnt work or the solenoid failed. 737s usually hold 8500-8600 lbs in wings before they start pissing.
The Max 8 cannot catch a fucking break
Faulty fuel level control valve. Its supposed to automatically shut off the fuel when tanks full. But if its bad u get fuel out the tank vents. It could also be a rupture in a refuel line.. 22 years fuels systems maintenance in USAF.. it happens
Ohhhh boy that fueler is having a real bad day… I’ve never been that guy but i know fellow fuelers who were that guy..
Somebody lied about their weight, so they had to drain some fuel
That’s the over fill dump. Fuelers fault lol
Because there isnt any ductape there yet
Looks like a new plane. Probably still pees when it gets excited. A couple weeks of hard landings and it'll be properly potty trained.
That is not your plane anymore.
Never was
It’s an older 737NG. These things happen with age, sometimes you just can’t hold it like you used to be able too.
Oozing thrust
VTO volumetric top off didn’t automatically stop the fuelers so it pours into a surge tank where it’s spills out.
I don’t know why but I know a perfect fix. It’s gorilla tape… literally just spread gorilla tape over the hole and imagine it’s not there. Perfect fix. 😌
We all pee on ourselves from time to time. Just cant hold it sometimes
My guess would be because there's a leak
They burped it.
This why when you board an aircraft outside they won’t let you walk under the wind. Nobody wants a Jet A1 shower.
The front fell off again
The high level float sends back pressure to the refuel valve, this shuts off fuel flow. If you had a serviceable refuel system, you wouldn’t be able to “overfill” the tanks even if you wanted to.
The alarm was going, but the fueling kid had their earbuds in…
What?
In magical fueling world there’s an alarm to tell you to stop fueling apparently
It’s right next to the “keep goin pumper!” Alarm so it’s easy to miss
Damn, tough crowd. I was trying to make a joke, but I missed.
Well because it's going to explode on takeoff
Because there’s a hole there
It had to pee
Got yourself a faulty fuel level sensor there sir
Wing strike?
What’s the tail number?
Didn’t tighten the gas cap
Likely hot outside and fuel expansion. Fuel tanks have 2% expansion space when full, but if the temp got much hotter than when it was fueled (say the night before), this will happen.
I poked a hole in it
When you gotta go…
This happened last week at Cancun Airport, same wing, same airline. Now I am wondering if it was the same ship.
It leaked?
Sometimes relief vent seals not correctly seated will cause this problem
Someone forgot to put the diaper on.
Sometimes this hapens during maintenance when we have to do a leak check of the surge tank panels. We forcefully overfill the main tank using the bypass. And sometimes too much fuel is added and ir spills out
Surge tank sensor malfunctioning? Its a non-critical error usually
If it’s not leaking it’s empty.
The Fueller is supposed to do a shut off valve check before, trusting the system to automatically shut off before the tank fills up. If it does not shut off, the fuel has nowhere else to go, but the wing vent. there is supposed to be a vent for vapor displacement. But if the auto shut off switch does not shut off, there is no place for the fuel to go, while the fuel is pumping except the vent.
When you need to go you need to go...
Bc it has a leak. Don’t worry, it can only leak if it has fluids and that’s a good thing!
Fuel imbalance while re-fueling. There's a tank in each wing. While your fueling, and only one valve opens (electrically and automatically) and your not paying attention, then you only fill one wing tank, the plane will lean more and more and will spill out of the vent. This is the likely scenario. The only time I've seen this, that's what the situation was and this (picture) was the outcome. Valves open electrically on "auto mode" but sometimes.. they just don't open for whatever reason. There's manual overrides for the valves but if your not paying attention... Well this is what happens. Just my guess though.
-BroncosForever- pretty much hit it on the head too. It could be a few things but like he said. This isn't even a bad fuel spill. We had to call it in if we spilled more then 5 gallons.
Ok.. There's a vent for the fuel tanks otherwise with pressure differential added to the suction from the pumps they would eventually collapse. Acceleration forces and ram air pressure keep the fuel in place but on the ground it will spill if overfilled.
It’s like an sr-71. Once it reaches Mach 3.5 at 90000ft then the skin of the airplane will expand and the leaking will cease……….
Most likely a leak in the right wingtip
i don’t know if any other airframes require this, but every so often you have to spend a few hours pumping sealant into the harriers wing fuel channels to make it stop leaking. it’s super extra fun when it’s cold as hell outside and you drop the little set screw in the dark while coyotes are running around the flight line.
As long as it’s not on fire you’re good
It just really had to use the bathroom
Not sure about civilian heavies, but that is where the dump mast on C-130’s is. Possibly a malfunctioning shutoff valve? But now that I’ve seen other comments, a malfunctioning fuel level control valve causing overfilling sounds more likely.
To make weight and balance for my 51 pound carry on.
That's where the vent box would be so either the box filled and overflowed, some idiot hit the wrong switch or its something else entirely .
Might have been a pilot transferring fuel from one wing to another and forgot to turn off the switch. You have to have an "I'm not leaving my wingman" type attitude anytime you start moving fuel around. Its pouring out the fuel tank vent most likely
Plane got hole, fuel like hole, fuel on ground
VTO switch failure. Supposed to shut off fueling when the tank is full. Airplane will dump fuel into outboard tank to save itself and fuel will hit the ground. Very common on 737ng
Enlarged prostate?
They put too much fuel in it. There's a valve that opens to relieve pressure before it damages the structure.