fuel values

[prasanna]

i have often heard on the radio , pilots asking for fuel. they request something like 4.7 which i assume is 4.7 tonnes. they also mention taxi 250 kg etc. what does it mean ...the fuel used for taxi ? why should they tell the ground this info( about taxi values) . they also mention something called burn ...what is that and why should the ground ops people know?

thanks

prasanna

[FL310]

well little girl, there is a bunch of uniformed drivers sitting in an aeroplane knowing that this machine will fly if the weight and balance of said bird is inside the constructors recommended limits.. .Since these mentioned push-button operators are off aviation school since quiet some time, none of them is in the position to manually compile a legally required load and trim sheet within the turn-around times the employer of a.m. aviators dictates to acchieve.. .Due to aforementioned reason, well trained keyboard operators need input data to have electronic devices calculate the actual weight and balance protocol.. .The block fuel is the amount of fuel a captain of an aeroplane accepts as to have an board after the fuelling is finished. A lot of decisions about the amount are based on weather, actual payload, company directives, fuel prices etc.. .The taxi fuel is the amount of fuel which is assumed to be burnt off before the aeroplane actually lifts off the ground. . .With the block fuel minus the taxi fuel the amount of fuel on board is the actual "lift-off" fuel. This amount is necessary to know as the moment of lift-off is the first moment where the aeroplane needs to be in the a.m. designed envelope. There are still more calculations required but, as already pointed out, all else is done by magic bits and bytes transfer.. .Hope this does clarify most of your questions.... . :)

[Pegasus77]

If she really is an anaesthesist, I doubt she is still a "little girl"... my dad took some time to become one.. .At home we once talked about how similar the two professions in some ways are.

Although I doubt as well that an anaesthesist would need to listen in on a company frequency of an airliner :)

[Herod]

Hey FL310, don't be so patronising! For a start, you've made an assumption that the person concerned is female, secondly that "she" is young and presumably ignorant. Incidentally, since I gather the quadripuff isn't RVSM compliant, shouldn't you be changing your name to FL280?

[Flight Detent]

Hi all,. .I'm with you "Herod", what a jerk!

Simply:. .The large number is for the fuel to be aboard after refuelling is complete.. .The taxi fuel is exactly that, the fuel expected to be used during departure taxi.. .The 'burn' is the calculated fuel used, after take-off, to the destination.. .The ground guys need this info to calculate the total weight, and it's distribution about the airplane, to check that the centre of gravity is within allowable limits. ie the pilot doesn't get a really big surprise at lift-off that the aircraft is really nose or tail heavy!. .The burn also allows them to check the expected fuel on arrival is within that allowed to enable the airplane to go to another airport in case of any problems at the original one. ie. weather bad or another airplane crashed on the only available runway or too long a wait to land due other traffic ahead. This alternate fuel is aboard and is additional to that required to fly to the planned destination.. .Hope I haven't oversimplyfied too much!. .Cheers.

[Justforkix]

A small correction, Burn is Trip + Taxi fuel.

Taxi fuel: is for engine start and taxi into takeoff position.

Trip fuel: is from start of takeoff to landing.

[prasanna]

thank you everybody for clearing the fuel queries.. .yep ... i am an anesthetist .. .occasionally i like to listen to airband company ops , becoz they are more interesting than radar vector heading etc.

anesthesia has a lot in common to aviation ...including check lists and simulator training !

like aircraft , once the patient is under the machine , you can 't start repairing things . so we have a pre operative machine check list ....etc ..

. .prasanna