I was just wondering if you fill the wing tanks, do you have to include the fueselage tank in the ZFM?Comments appreciated.Cheers[br][/img]

Here's the limitation from my 757 operating manuel.Center Tank Fuel When Wings NOT Full:Up to 2000 lbs may be carried if ZFW + center tank fuel is less than 184,00 lbs. (184,00 lbs is the maximum ZFW)So center tank fuel is considered part of zero fuel weight only if the wings are not full and then only 2000 lbs.Hope that helps.

Cheers tallpilot :)Cheers[br][/img]

Ben,ZFM combines APS weight, Crew & Catering weight and Payload.APS weight = Aircraft Prepared for service weight - ie totally empty.This will include the weight of the empty fuel tanks.In the many hundreds of 757/767 loadsheets that I have produced, I have yet to include any Ballast Fuel in the Centre Tank on the Loadsheet.Loadsheets work out the fuel index based on the total fuel loading.Mark

Mark,I know that much (well I should do! lol. ATPL's in 2 weeks! :( ) but I was just wondering because of the load on the wing roots is dependent on the weight contained at the arm datum I.E - the fueselage. That's why ZFW is limited to start with. I was just wondering if centre tank fuel is added to the ZFW as it adds to the stress of the wings at the root. Cheers anyway[br][/img]

Ben,good luck with the ATPLs.I have looked out a Boeing AHM50 I have for the 767-300. This is input into a template in the DCS computer systems that do loadsheets.Fuel Loading and Index Values:Below 30000Kgs the Index Value changes between +0.1 and +3.20 units depending on the amount of fuel loaded.Wings Full the Index change is +10.90 units.Between Wings Full (36400Kgs) and 52000Kgs the Index changes from +10.90 units to +0.00 units.Between 52000Kgs and Max Fuel (72619Kgs) the Index Value changes from +0.00 to +15.80 units.If fuel loaded greater than 34023KGS FWD ZFM Limit = +21.70 unitsAFT ZFM Limit = +70.70 unitsIf fuel loaded less than 34023Kgs FWD ZFM Limit = +21.70 unitsAFT ZFM Limit = +74.70 unitsIt looks as if the docs supplied by Boeing take into account the differences in wing loading at different fuel loads, eg the smaller changes in Fuel index Value and the higher AFT ZFM limit when the Centre Tank is not used.This would suggest that the Centre Tank Fuel is not added to the ZFM.I know that some aircraft have ballast fuel tanks in the tail, and this can be added accounted for in the loadsheet.Maybe the tech Log forum in pprune would be able to give a more definitive answer.Mark

Forgot the part about the 1000 lbs in the center tank to keep the pumps covered.....(chuckle) Old manual?Missed meeting you at the 727 retirement party last month.Enjoy LASTim_757

Ben,found some more stuff out for you:Centre Tank Fuel (used either as ballast or as Tim_757 says to adhere to the Boeing AD about having 1000lbs fuel in the centre tank to keep the pumps covered) is added to the APS weight as a Service Weight Adjustment. This basically adds the weight of the Fuel in the centre tank and the Index effect of this fuel onto the DOW and DOI.I know that BA are using this policy on some of their 757 fleet.Works out at around 300Kgs is added to the DOW weight of the aircraft.The DOI changes by about 0.2, although I cna't remember if this is +/-I don't think this additional fuel would greatly impact on the payload allowable. Most ZFW Limited flights (757) I have seen are to "golf" destinations - Malaga or Faro. I have seen one flight where 1/2 the belly water was ditched, 1 crew member and 80+ sets of golf clubs just to get the aircraft under the MZFW limit.Hope this helps some more.Mark