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Fuel Quantity Verification  
User currently offlineDelta2058 From United States of America, joined Jul 2009, 18 posts, RR: 0
Posted (4 years 11 months 2 weeks 6 days 18 hours ago) and read 11131 times:

Once the crew determines the fuel load for a flight, how to they verify that the correct amount is onboard? Is the digital readout on the EICAS sufficient or is there a way they double check that the indicated fuel is indeed onboard?

How common is it to have to off-load fuel to reduce weight before takeoff? Is this done by simply pumping it out of the plane back into the fuel truck?

I imagine the process is pretty efficient since a crew may inherit a plane with an inappropriate fuel load for the next leg.

Thanks.


Smooth seas do not make skilled sailors.
38 replies: All unread, showing first 25:
 
User currently offlineDALMD88 From United States of America, joined Jul 2000, 2533 posts, RR: 14
Reply 1, posted (4 years 11 months 2 weeks 6 days 17 hours ago) and read 11137 times:

Fuel quantity readings are usually fine. If the gage or the system is inop they can go out to the wing and use a dipstick type of reading. The dipstick is actually less acurate. The capacitance system takes into account the density of the fuel. The dipstick is just a volume reading. The fuel sticks are found on the bottom of the wing.

User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 2, posted (4 years 11 months 2 weeks 6 days 17 hours ago) and read 11122 times:

First the dispatcher determines the fuel load and the capt accepts it or request more. In the jet the F/O tallys the arrival fuel slip with the upload fuel slip to compare what the fueler has put on board. This info is entered into ACARS and uploaded to ops. This should reflect the fuel gauges qty. Also on the -11 there's 2 sets of fuel qty indications.

User currently offlineFr8mech From United States of America, joined Sep 2005, 5330 posts, RR: 14
Reply 3, posted (4 years 11 months 2 weeks 6 days 16 hours ago) and read 11107 times:

Take the fuel remaining, add the fuel uplifted and you have total fuel onboard.

The fuel uplift number (usually, in gallons) comes from the meter on the truck. Therefore, you will have 2 seperate indication systems, aircraft and truck, working together to get the right number. If the aircraft system is off, the total fuel won't tally, same with the truck.



When seconds count...the police are minutes away. Never leave your cave without your club.
User currently offlineMender From United Kingdom, joined Feb 2004, 240 posts, RR: 0
Reply 4, posted (4 years 11 months 2 weeks 6 days 13 hours ago) and read 11048 times:



Quoting Delta2058 (Thread starter):
a crew may inherit a plane with an inappropriate fuel load for the next leg

Very rare, the aircraft would normally have very little fuel remaining when it lands so it nearly always needs additional fuel to go anywhere. I know sometimes the crew will "tanker" (take off with round trip fuel load) but again the aircraft will rarely need to defuel.

If they do need to defuel it can take a long time to find an empty bowser to receive the fuel so it's avoided at all costs.


User currently offlineTristarSteve From Sweden, joined Nov 2005, 3976 posts, RR: 34
Reply 5, posted (4 years 11 months 2 weeks 6 days 10 hours ago) and read 11024 times:



Quoting Mender (Reply 4):
If they do need to defuel it can take a long time to find an empty bowser to receive the fuel so it's avoided at all costs.

Fuel companies keep their bowsers full. It keeps the air out of the tank, and reduces the amount of water in the fuel (The water precipitates out of the air).
So if you need to defuel, first you have to ask the fuel company to empty a bowser. If you are lucky and a widebody is awaiting refuelling, this may happen in 45 mins., If you have a row of props, it could take a few hours. Then when you defuel, the fuel in the bowser is yours. It cannot be sold to anyone else. It either goes back into one of your planes, or is disposed of.

We all know this. When refuelling, you are always very careful not to cause problems by putting on too much. When a plane is standing on the ramp with too much fuel, then OPS tries to work out how to use the aircraft without defuelling. If it is landing weight limited, they may just increase the routing to use the fuel. Its much cheaper than defuelling! Or they may put it on another service, or offload the freight. Anything to save defuelling.


User currently offlineJoseKMLB From United States of America, joined May 2008, 493 posts, RR: 0
Reply 6, posted (4 years 11 months 2 weeks 6 days 4 hours ago) and read 10962 times:



Quoting DALMD88 (Reply 1):
dipstick type of reading

Hate that dipstick if you pull it out the wrong way and get fuel on you if you cant see the arrow on it.


User currently offlinePhoenix9 From Canada, joined Aug 2007, 2546 posts, RR: 8
Reply 7, posted (4 years 11 months 2 weeks 6 days 4 hours ago) and read 10950 times:



Quoting JoseKMLB (Reply 6):
Hate that dipstick if you pull it out the wrong way and get fuel on you

Heck, if you don't pull out on time, things can get pretty serious with wife/gf.

(sorry couldn't resist)

------

Anyways...on topic, so does each of the airport calibrate their equipment to standard temperature? or does it vary from hot to cold climates. Since the temperature will change density of the fuel, wouldn't it affect the amount loaded?



Life only makes sense when you look at it backwards.
User currently offlineJoseKMLB From United States of America, joined May 2008, 493 posts, RR: 0
Reply 8, posted (4 years 11 months 2 weeks 6 days 2 hours ago) and read 10924 times:



Quoting Phoenix9 (Reply 7):
Heck, if you don't pull out on time, things can get pretty serious with wife/gf.

(sorry couldn't resist)

Funny guy there lol.

Pilots cockpit readings are very good to the fuel load on their airplanes, but when the plane has an inop fuel gauge the pilot has to put all his trust into the fuel er that he fueled the plane the right way. If he measured the pitch and roll of the aircraft wrong like saying the pitch is 2.5 but it really is -2.5 he can miss fuel that airplane and make a bad imbalance of the plane.



Quoting CosmicCruiser (Reply 2):
First the dispatcher determines the fuel load and the capt accepts it or request more

Seen it alot of the times when the pilot asks for a few hundred or so pounds when they know bad wheather will be at their dest. airport.


User currently offlineValkyrie01 From United States of America, joined Mar 2007, 72 posts, RR: 0
Reply 9, posted (4 years 11 months 2 weeks 6 days 1 hour ago) and read 10915 times:



Quoting JoseKMLB (Reply 8):
Pilots cockpit readings are very good to the fuel load on their airplanes, but when the plane has an inop fuel gauge the pilot has to put all his trust into the fuel er that he fueled the plane the right way. If he measured the pitch and roll of the aircraft wrong like saying the pitch is 2.5 but it really is -2.5 he can miss fuel that airplane and make a bad imbalance of the plane.

Where can i find those fueler at. I know when we have an inop fuel gauge mx has to go and verify the correct amount of fuel is loaded. Known fuel quanity , fuel stick etc



The best there is the best there was the best there ever will be
User currently offlineDc8friendship From United States of America, joined Apr 2005, 242 posts, RR: 3
Reply 10, posted (4 years 11 months 2 weeks 6 days ago) and read 10909 times:



Quoting TristarSteve (Reply 5):
It cannot be sold to anyone else. It either goes back into one of your planes, or is disposed of.

Wrong! that has to do with company policy, and whether a buyer is willing to buy "used" fuel. but as long as it is clean, it is legal to resell defueled fuel.



Come fly the Friendly Skies of United
User currently offlineHAWK21M From India, joined Jan 2001, 31667 posts, RR: 56
Reply 11, posted (4 years 11 months 2 weeks 5 days 22 hours ago) and read 10885 times:



Quoting JoseKMLB (Reply 6):
Hate that dipstick if you pull it out the wrong way and get fuel on you if you cant see the arrow on it.

Not all Aircraft have Dripsticks,some have Fuel measuring sticks that don't drip but show the fuel level via a magnetic float holding the stick.

Out here Defuelling requires a seperate Bowser & can take approx an hour to be ready as no fuelling company keeps one empty.

After knowing the departure fuel in Kgs,deducting the Arrival fuel in kgs from this.One knows the Fuel uplift needed in kgs,knowing the Sp gravity of the Fuel being supplied,the uplift in litres can be calculated to be a cross check.

regds
MEL.



Think of the brighter side!
User currently offlineTristarSteve From Sweden, joined Nov 2005, 3976 posts, RR: 34
Reply 12, posted (4 years 11 months 2 weeks 5 days 14 hours ago) and read 10834 times:



Quoting Phoenix9 (Reply 7):
Anyways...on topic, so does each of the airport calibrate their equipment to standard temperature? or does it vary from hot to cold climates. Since the temperature will change density of the fuel, wouldn't it affect the amount loaded?

Fuel on board aircraft is measured in weight, kgs or lbs.
Fuel delivered is measured in volume, litres gallons or US gallons.
So we have to multiply the delivered fuel volume by the specific gravity to get it into weight, which can then be compared to the aircraft weight of fuel.

So if an aircraft arrives with 2000kg on board, and I pump in 10000 litres, and the density (spec gravity) is 0.8 then I have added 8000 kg, and the fuel gauges should read 10000 kg.
Each airline has an allowed discrepancy, about 300kg on an A320 up to 2000kg on a B744. If the sums match you are OK.

The density is measured when refuelling. The bowser will deliver a couple of litres into a bottle and a floating gauge measured the density. This will change all the time, but from the same refinery will be higher in the winter and lower in the summer, Here it ranges from 0.810 in winter down to 0.790 in summer. It is basically temp dependent. But different refineries deliver fuel at different SGs.
The airlines like high SG fuel. They pay by the litre. High SG fuel gives you more energy per litre, so you need less litres to fill the tanks.


User currently offlineJoseKMLB From United States of America, joined May 2008, 493 posts, RR: 0
Reply 13, posted (4 years 11 months 2 weeks 5 days 9 hours ago) and read 10790 times:



Quoting Valkyrie01 (Reply 9):
Where can i find those fueler at. I know when we have an inop fuel gauge mx has to go and verify the correct amount of fuel is loaded. Known fuel quanity , fuel stick etc

Well try ASIG here when I was a fueler now I just do ramp but DL holds a class for inop fuel gauge's for each plane they have and when I did it it was back in the L-1011 and 727 days. But they still hold the classes. Its not hard at all to do the plane. Most planes have more than one way to do them like cockpit gauge's, meter, fuel transfer from tank to tank, and drip/magna stick. As long as we did the class and passed it we do not need a mx to come check it out.

Quoting HAWK21M (Reply 11):

Think most if not all boeing planes have the dripstick. The 737-200 seemed like for DL always had an inop gauge. The MD-88 has the magna stick


User currently offlineValkyrie01 From United States of America, joined Mar 2007, 72 posts, RR: 0
Reply 14, posted (4 years 11 months 2 weeks 5 days 2 hours ago) and read 10751 times:



Quoting JoseKMLB (Reply 13):
Well try ASIG here when I was a fueler now I just do ramp but DL holds a class for inop fuel gauge's for each plane they have and when I did it it was back in the L-1011 and 727 days. But they still hold the classes. Its not hard at all to do the plane. Most planes have more than one way to do them like cockpit gauge's, meter, fuel transfer from tank to tank, and drip/magna stick. As long as we did the class and passed it we do not need a mx to come check it out.

Where you authorized to make a log book entry and signed it off? lets take a 737 for example a fuel quanity indicator for the main tank is inop,it's place on MEL.Part of the MEL is prior to each departure verify the fuel quanity in the associate main tank and record successful accomplishment in the aircraft maintenance logbook.Well thats how it is for the airline i work for,maybe other airlines do it different.



The best there is the best there was the best there ever will be
User currently offlineJetMech From Australia, joined Mar 2006, 2684 posts, RR: 53
Reply 15, posted (4 years 11 months 2 weeks 5 days 1 hour ago) and read 10748 times:



Quoting JoseKMLB (Reply 13):
Think most if not all boeing planes have the dripstick.

The 747 (and 767?) has dipsticks. The 707 had dripsticks. Not sure about the types in-between the 707 and 747 however, but I presume that the 777 would have dipsticks. A330 / A340 also use dipsticks.

Regards, JetMech



JetMech split the back of his pants. He can feel the wind in his hair.
User currently offlineEcuadorianMD11 From , joined Dec 1969, posts, RR:
Reply 16, posted (4 years 11 months 2 weeks 5 days ago) and read 10742 times:

Would it be possible to post a pic of a dipstick?
(And I´m not referring to Delboy & Rodney Trotter).

I wonder where exactly this stick is positioned (on an average modern jet liner) and how you can pull out a plug out of the bottom without getting drenched.
According to some posts on this thread there is a "right" and a "wrong" way of doing it........(like drinking beer out of boot-shaped glass) but I find it hard to picture how this system would work.

I work with fuel tank soundings and sounding tape etc myself so the whole subject is not too uncommon for me!

Cheers,

Ecuadorian MD11.


User currently offlineJoseKMLB From United States of America, joined May 2008, 493 posts, RR: 0
Reply 17, posted (4 years 11 months 2 weeks 4 days 21 hours ago) and read 10735 times:



Quoting JetMech (Reply 15):

OK the 727 and the 737s had the drip sticks those were the planes that I was use to having the dripstick and not really thinking about the 57 and on.

Quoting Valkyrie01 (Reply 14):
Where you authorized to make a log book entry and signed it off? lets take a 737 for example a fuel quanity indicator for the main tank is inop,it's place on MEL.Part of the MEL is prior to each departure verify the fuel quanity in the associate main tank and record successful accomplishment in the aircraft maintenance logbook.Well thats how it is for the airline i work for,maybe other airlines do it different.

There was no log entry to sign off for a inop gauge on DL A/C the only thing we had to do is fill out our FSR (Fuel Service Record) and hand it over to the pilots. This is what we would do on arrival of the plane. First get the grid charts for the plane that is coming in, 2nd we would pull down the drip stick(737-200) and measure what the fuel qty is for the tank, 3rd after getting the fuel qty you would get in the main gear door area to measure the pitch and roll of the plane, 4th you would go to the grid charts and see what settings on the drip stick should be set at for the certain fuel load, 5th you would then pump fuel into the tank until fuel started to drip from the stick and you would stop, and last you would fill out the FSR and turn it in. The only time MX would have to check it was if there were no person that passed a inop gauge class.

Quoting EcuadorianMD11 (Reply 16):
I wonder where exactly this stick is positioned (on an average modern jet liner) and how you can pull out a plug out of the bottom without getting drenched.
According to some posts on this thread there is a "right" and a "wrong" way of doing it........(like drinking beer out of boot-shaped glass) but I find it hard to picture how this system would work.

I work with fuel tank soundings and sounding tape etc myself so the whole subject is not too uncommon for me!

Cheers,

Ecuadorian MD11.

The sticks are under the wing and there should be 4 down the line you pull out which ones you need to use via your grid charts. Some have the dripsticks with arrows that show which way the fuel will drip out and others have the magnasticks in them which dont drip out.


User currently offlineHAWK21M From India, joined Jan 2001, 31667 posts, RR: 56
Reply 18, posted (4 years 11 months 2 weeks 4 days 21 hours ago) and read 10733 times:



Quoting JoseKMLB (Reply 13):
Think most if not all boeing planes have the dripstick.

Not on a B757.
regds
MEL.



Think of the brighter side!
User currently offlineBoeing767mech From United States of America, joined Dec 2000, 1025 posts, RR: 3
Reply 19, posted (4 years 11 months 2 weeks 4 days 20 hours ago) and read 10726 times:



Quoting HAWK21M (Reply 18):
Quoting JoseKMLB (Reply 13):
Think most if not all boeing planes have the dripstick.

Not on a B757.
regds
MEL.

Then how do you stick the tank?????
David



Never under-estimate the predictably of stupidty
User currently offlineFr8Mech From United States of America, joined Sep 2005, 5330 posts, RR: 14
Reply 20, posted (4 years 11 months 2 weeks 4 days 19 hours ago) and read 10715 times:



Quoting JoseKMLB (Reply 13):
Think most if not all boeing planes have the dripstick.

I haven't worked the B737-xxx, but I've worked B727/747/757/767 and only the B727 has drip-sticks. The rest have magna-sticks.

Quoting EcuadorianMD11 (Reply 16):
I wonder where exactly this stick is positioned (on an average modern jet liner) and how you can pull out a plug out of the bottom without getting drenched

Depending on aircraft, there can be more than one per tank. On a magna-stick (dipstick) the stick is inside a housing. The housing is inside the tank. The tip of the stick is ferrous or a magnet. Around the housing is a donut magnet that is free to float up and down with the fuel level. When you pull the stick, it should be dry.

A drip stick, on the other hand, is wet. It is a hollow tube. When the top of the tube reaches the top of the fuel, the tube fills and fuel comes out the bottom. The arrow on the bottom will point in the direction the fuel should come out.

Both sticks are usually graduated in inches and there are charts to convert from inches to fuel weight.

Hope that makes sense.



When seconds count...the police are minutes away. Never leave your cave without your club.
User currently offlineJoseKMLB From United States of America, joined May 2008, 493 posts, RR: 0
Reply 21, posted (4 years 11 months 2 weeks 4 days 12 hours ago) and read 10686 times:

Yeah for some reason I thought most Boeing A/C had the drips but only the 727 and 37s have them you guys are right about the 57 on with the magna sticks. I was just remembering with what planes we worked on. Now I know the 37-200 has the drips I really dont know about the 800 if they are the drips or magna?

User currently offlineJetMech From Australia, joined Mar 2006, 2684 posts, RR: 53
Reply 22, posted (4 years 11 months 2 weeks 4 days 2 hours ago) and read 10640 times:



Quoting Boeing767mech (Reply 19):
Then how do you stick the tank?????

I suspect it may be with a dipstick on a 757. Going by the posts in this thread, it appears that Boeing changed over from drip-sticks to dipsticks after the 737 classic.

Regards, JetMech



JetMech split the back of his pants. He can feel the wind in his hair.
User currently offlineJoseKMLB From United States of America, joined May 2008, 493 posts, RR: 0
Reply 23, posted (4 years 11 months 2 weeks 3 days 23 hours ago) and read 10624 times:



Quoting JetMech (Reply 22):

Yeah they have the magna sticks in them.


User currently offlineHAWK21M From India, joined Jan 2001, 31667 posts, RR: 56
Reply 24, posted (4 years 11 months 2 weeks 3 days 22 hours ago) and read 10613 times:

Quoting Boeing767mech (Reply 19):
Then how do you stick the tank?????

Using Measuring sticks.

Quoting Fr8Mech (Reply 20):
Depending on aircraft, there can be more than one per tank. On a magna-stick (dipstick) the stick is inside a housing. The housing is inside the tank. The tip of the stick is ferrous or a magnet. Around the housing is a donut magnet that is free to float up and down with the fuel level. When you pull the stick, it should be dry.

A drip stick, on the other hand, is wet. It is a hollow tube. When the top of the tube reaches the top of the fuel, the tube fills and fuel comes out the bottom. The arrow on the bottom will point in the direction the fuel should come out.

Both sticks are usually graduated in inches and there are charts to convert from inches to fuel weight

Thats correct
Fuel tank Measuring sticks is the term used on the B757.
Customer option for the measuring sticks can come in units of Inches/pounds/litres or kgs.

regds
MEL.

[Edited 2009-08-09 02:45:27]


Think of the brighter side!
25 EcuadorianMD11 : Yep, it does.........very much so. The magnetic donut goes around the housing of the dipstick and sits at a certain level as it floats on top of the
26 JetMech : In addition to the actual depth reading, you will also need to know the attitude of the aircraft. On the 747 for example, there are two spirit levels
27 GLEN : The fuel uplift is normally very clean. However in the tanks there is some accumulation of water over time (condensed water out of the air). On the A
28 Pilotpip : At both FBOs I worked for back in the day we had to do a quality control check on the fuel before accepting it from the refinery. It was then filtere
29 HAWK21M : Quality control checks are carried out by the Fuel vendors on their Storage & delivery facilities reguralarly.In addition pre,mid & post fueling samp
30 Surfpunk : When I worked at MSP, we were not certified to perform inop gauge work ourselves (other than the actual delivery of the fuel). MX for the airline woul
31 JETPILOT : As an FE on the DC8 some years ago our company procedure on international flights was to drip the tanks. I remember doing #1 and #4 aux tanks which ar
32 HAWK21M : Refuelling with an INOP fueling valve is much more time consuming on a B757 in comparism to a B737. regds MEL.
33 JoseKMLB : Yeah each morning we use to sump the trucks and the planes that sat for over 3hrs. Now I don't even think they sump the planes anymore, but when I di
34 Lh526 : Jet A1 in comparison to the Jet A has a lower freezing point (−47 °C vs −40 °C) and several additives. Jet A1 is usualy provided outside the US
35 Tdscanuck : There's also TS-1, the Russian version of Jet A1, and JP-4, an older wide-cut fuel. Some older aircraft are certified for JP-4, but most new ones are
36 HAWK21M : Out here only Draining for water extraction on a 24hr halt a couple of hrs prior to refuelling & complete draining of the tanks carried out during a
37 Crjfixer : We sump ours every 3 days on a service check (CRJ-200)
38 Post contains images Sfotom : This is the bottom of the wing of a 737-300. The fuel stick is the dark spot in the tank entry plate. Depending on when they came off the line, 737-3
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