Page 2-8 Cruise and Fuel Planning (PMDG)Distance: interpolate time and fuel ex: 5400@fl410 equals 11:15 and 104,100kgs.How did they come precisely to this figure?Are there any more detailed charts ready to use with all intermediate trip lenght like 6900-7000-7100 etc...?Thanks for your attentionRegardsRakhamToshiba Satellite P4 3.4 Ghz1536 DDR RAM nVidia GeForce FXWinXP Home on the road andPIV 3.4Ghz, 1536 DDR RAM, ATI Radeon 9700 WinXP PROYoke & Pedals CH Products at home

No other "detailed charts" are needed since simple linear interpolation is good enough. The distance of 5400 falls right in the middle of table values 5200 and 5600 - hence the interpolation in this case is trivial. Even in the more difficult cases it is no more than high-school algebra which you can perform in your head with no pen and paper needed. Since we are only 'estimating' fuel needed - it is easy to see that 'exact' numbers are not necessary.Michael J.http://www.precisionmanuals.com/images/for...argo_hauler.gifhttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

I've never really bothered with those tables, I've recorded fuel usage over a number of flights and always seem to hit the same FF average of around 12,000Kgs per hour, so I just multiply that by the expected flight time to get an estimate of whats required.Simple I know, but works great for me :D

Here's the general skinny on interpolation3500nm flight at FL290 - fuel required 75,300lb 4000nm flight at FL290 - fuel required 85,500lb Distance was 3800nm, so, the manual tells me to "interpolate" ... divide the 10,200lb difference by 500nm which worked out to 2,040lb per extra 100nm. Multiply that by 3 and it equals 6,080lb added to the 75,300lb. So my burnout fuel would be 81,380lb.

Ben thank you very much for your time and clear explanation. Hope many more will enjoy this. Tomorrow I will enter this in Excel and hope we find the right formula. We had been working on this several hours but we were always some 10-15 minutes apart!RegardsRakhamToshiba Satellite P4 3.4 Ghz1536 DDR RAM nVidia GeForce FXWinXP Home on the road andPIV 3.4Ghz, 1536 DDR RAM, ATI Radeon 9700 WinXP PROYoke & Pedals CH Products at home