question using Bob Scott's FDE

[Guest bisinchi]

Hi,I am using the latest FDE from Bob Scott on a A340-300 and have a question concerning taking off with a heavy A340:I took off with a 526 000 airplane from LFPG (324 000 empty weight and 202 000 fuel) to FMMI (Antanarivo in Madagascar) temperature was about 14 degrees C (Not sure about farenheit, but somewhere in the 60s I would say) and went through the whole runway before being able to be airbone (pretty much used the whole of the 12000+ runway). The engines where used at max power. My question is: do I expect this, especially since I don't consider the plane to be mega heavy (A340-300 have a MOTW of 596 000), so I have room for margin there!! What is the max TO load of the plane with that FDE? I'm not looking to criticise the FDE (which I find excellent anyway!!), I'm just curious about the take off sequence, especially since I am looking at a longer (so heavier plane) take off in the near future.RegardsFrancois

[Bob Scott 7,711]

Francois; I'm looking at takeoff performance on the 340, and agree that it does look anemic, but right now I lack any sort of concrete performance data to base any changes on. Anyone out there have data showing takeoff ground roll for an A340-200/300? Please note this is not the same as balanced field length, or required runway for takeoff. I need takeoff ground roll data.RegardsBob ScottATP IMEL Gulfstream II-III-IV-V L-300Washington, DC

[Guest bisinchi]

Hi Bob,Thanks for your reply. I now understand where the problem come from.Do you think that the data you are lacking, could be given by a A340 pilot, or is that data, FS specific?Regards,Francois

[Bob Scott 7,711]

No, not FS specific...I need the takeoff ground roll chart(s) from the real AFM.RegardsBob ScottATP IMEL Gulfstream II-III-IV-V L-300Washington, DC

[Guest godinhoc]

Hi there ...Sorry , but what do you mean by 'takeoff ground roll data'I think I can help you ...Regards ...Carlos Godinho

[Bob Scott 7,711]

Carlos; I need the actual ground roll from brake release to liftoff. The charts are named somewhat differently from manufacturer to manufacturer...I don't have any r/w Scarebus manuals, so I do not know what the chart is called in their AFMs.RegardsBob ScottATP IMEL Gulfstream II-III-IV-V L-300Washington, DC

[Guest bisinchi]

Bob,Sorry for a stupid question: what is the difference between ground roll data and required distance to takeoff? Are these 2 different parameters?Regards,Francois

[Bob Scott 7,711]

Yes...they're significantly different numbers.The required takeoff distance is determined by assuming acceleration on all four engines at takeoff power to V1, then either losing an engine and continuing the takeoff with 3 engines (accelerate-go distance), or aborting the takeoff (accelerate-stop distance). The longer of those two distances is the required takeoff distance...and in the special case where the two distances are equal we call that distance "balanced field length."There are actually many more complexities...i.e. RCR, RSC, slope, stopway, clearway etc etc...but the bottom line is that the required rwy length for takeoff is quite different from the normal ground roll for takeoff with all 4 engines operating.RegardsBob ScottATP IMEL Gulfstream II-III-IV-V L-300Washington, DC

[Guest bisinchi]

Bob,So is there any way to find out how long it would take to take off at a specific weight with specific flaps settings and with specific engine power? Is that the information you are after?Regards,Francois

[Bob Scott 7,711]

Yes, this data most certainly exists in the AOM/FCOM somewhere. And yes...this is what I'm looking for.CheersBob ScottATP IMEL Gulfstream II-III-IV-V L-300Washington, DC

[Guest bisinchi]

Hi Bob,I'll see if it's possible to get that info, but that may take a lot of time (via a real life pilot). I'm not promising anything, but I'll try.Regards,Francois