what exactly is zero fuel weight??

[Guest gooper]

Hi to all I am slightly confused as to what exactly ZFW means when it is entered into the FMC- does it simp;ly mean the empty weight of the aircraft with the maximum number of passengers and crew as well as luggage or is it just the empty weight of the plane with no passengers, crew and luggage. appreciate all your help with understanding the proper meaning of this term.

[Guest]

Well, you are close enough in your first guess :)ZFW is exactly what it sounds like: weight with zero fuel.As you guessed the ZFW contains aircraft + everything loaded.... crew, catering, passengers, luggage, cargo, mail or what ever you like.The MaxZFW will then describe the stuctural weight limit that the airframe can cope without risk of being damaged.RegardsFredrik

[Guest]

Just to be clear because I can see how you could be confused... the ZFW you enter into the FMC is the actual, current ZFW for the flight you're about to make, not the maximum ZFW.That is made up of the aircraft prepared for service or Dry Operating Weight (DOW) together with the ACTUAL weight of it's payload i.e. passengers, baggage and freight. In PIC the ZFW is fixed at 245k lbs. You could edit this figure in the Weight and Balance section of the aircraft.cfg, but there's no reason to unless you're flying a very long range flight and you need more fuel. Essentially, as the ZFW goes up because your payload increases, the amount of fuel you can carry reduces.With modern widebodied aircraft, these calculations are a lot less critical than with previous generations of aircraft simply because they have much greater capacity to start with. I used to despatch RAF VC-10's and on winter westbound trans-Atlantic flights it was often necessary to shut off freight or less important passengers to reduce payload to permit them to carry sufficient fuel to reach Gander en-route to Dulles simply because of the prevailing winds. The first question the Captain would ask on arriving to start flight planning was "What's the ZFW?". The second was "What's the met?". The third was usually, "OK, how long will it take you to offload the frieght?!".Cheers,AndyEGTR

[Guest]

Or to put it even more simply:BW - Basic Weight - Empty Aircraft with catering and documentationDOW - Dry Operating Weight - BW + Operating CrewOW - Operating Weight - DOW + Take-off FuelZFW - Zero Fuel Weight - DOW + PayloadTOW - Take-Off Weight - ZFW + Take-off Fuel OR OW + PayloadLAW - Landing Weight - TOW - Trip FuelEasy innit :)Well allright I train people to do Weight and Balance for a living so should know a thing or two ....

[David Vega]

You said"In PIC the ZFW is fixed at 245k lbs."which I've read in the manuals too. But, shouldn't one change this as the payload changes? If not, could you explain why not? Thank you for the explanation. This is helping me too.Dave Vega

[Guest]

Dave,Indeed you should. I haven't looked for it, but to correct the ZFW you would first have to find the Dry Operating Weight, then add the payload (Pax, bags, cargo, mail) to get the correct ZFW.I would have liked to see PIC being released with a loading function, where one could not only add payload but also the distribution thereof. The distribution is important to calculate the MAC% (Mean Aerodynamic Chord) or the balance of the aircraft. A tail heavy aircraft burns less fuel, on a long-haul the fuel saving is quite considerable compared to a nose heavy aircraft.However this would also mean that one would have to adjust the stab trim settings, as this is based on TOW, Balance and flap settings.Would have been neat, perhaps in PIC for FS2004 ?

[David Vega]

Thanks for your reply. I use ACLoader at http://fsflightdeck.com/. It appears to distribute the weight as you specified. Again, thank you.

[Guest Mark McG]

Could be possible for PIC in it's current form.However, Would need a copy of an airlines AHM50, and plenty of time to develop as a stand alone programme.Mark