Balance Cargo and Fuel

[Guest mark_wilby]

Hi AllQuestion how do I balance cargo for fuel, I am using the cargo load utility that came with the 747-400F I know if I fill the aircraft up with cargo I sacrifice fuel so can

[Stuntie 0]

Use the fuel-distance tables in 2.7 and 2.8 as a guide to how far you can get given the fuel you have.Take off the taxi, alternate and contigency fuel first to figure out trip fuel amount.Decide on you cruise altitude and look down the table for that flight level till you get to your trip fuel level and look left to see what the trip distance is.This will give you a ballpark figure to work with range wise.A world map and a compass will give you the area you can cover.However, you are working the wrong way round.Airlines generally know where they are intending to fly to.Cargo flies routes just like cattle does so most freight goes on these routes.They calculate fuel needed to get there. Add in the dry weight and subtract that from max take off weight to give you an idea of max payload. This could be max load for a short flight, but probably wouls be less than max for most flights.The trade off here is cargo for range, and as the range is set it's the cargo weight that needs to be lowered if needed for max weight.This is a ball park figure and they would no doubtcheck the fuel figures again once cargo weight is known to be sure.Most operators will no doubt have limitations and procedures so as to avoid aircraft overloading. I also doubt that they fly max weight every trip as well. Some cargoes are bulky not heavy etc. And running max weight all the time could be bad for the airframe so there may be weight limits to prolong airframe life etc.(Having said all that I'm no airline pilot so I could be spouting bovine excrement. No doubt someone will correct me.)P.S. Watch out when flying from more interesting places such as parts of Africa.Their cargo weight sheets may be a little out.One of the guys in the street who loadmastered for a while remembers some real scrape the tail on the end of the runway and pray type takeoffs from Africa with cargos that were a lot lot heavier than the load sheets said.

[Guest Hawkeyeted]

Mark,Here is a link to Boeing's aircraft advanced technical details on the 747 family:http://www.boeing.com/assocproducts/aircompat/747.htm Check section 3: "Performance", under the respective airframe (-200 or -400) The documents for each family contains all derivitives of the model.In there is everything you would ever need to know regarding the performance of the 747, including range/weight charts.