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Old 3rd Jun 2006, 01:04
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Bealzebub
 
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I still don't fully understand the nature of the problem here.

The flight planning paperwork (plog) should show how the fuel requirement is calculated. For simplicity and without going into the constituent sub requirements of each section, this should be :

A) Taxi fuel.
B) Trip fuel.
C) Contingency (5% of Trip fuel).
D) Alternate fuel.
E) Final reserve fuel ( 30 minutes holding fuel ).

In a situation ( as you describe) where you are limited by max landing weight, the maximum take off weight is ordinarily the MLW + (B)
The maximum ramp weight is MLW + (A+B).
Having arrived at this figure (x) you then deduct the aircrafts dry operating weight (DOW) plus the minimum fuel required (items A-E) giving you a wet operating weight, from the figure (x). This is your maximum payload.

The plog may well calculate for each leg a proportion of the contigency fuel used throughout the trip to show a fuel figure on arrival that would amount to items (D + E) in other words the normal minimum fuel required at destination. These plog waypoint figures are provided to show the how the fuel remaining at any given waypoint should be in order to arrive at destination with minimum diversion fuel ( D+E) onboard. The planning system that I am familiar with does not include the 5% contingency figure, but possibly yours does ? However in any event the planning fuel and payload derived would be unaffected. This waypoint figure simply provides a reference number for your actual fuel onboard computation at any given time , in order to establish a trend. Again I would make the point that by using the calculations from the fuel block (as described above) even if the contingency fuel was unused during the flight you should not ordinarily arrive in excess of your MLW.

If you are saying that your planning system ( for some reason ) incorporates items (B+C) into one trip fuel figure, then that contingency element needs to be seperated prior to calculating the payload allowable figure. If you are saying this is not being done, then your company is seemingly applying an erroneous method of flight planning and not using the documentation properly. However I would again make the point that the trip fuel can be increased to whatever you require so long as it is sufficient for the planned flight and the minimum required fuel is onboard at destination. That does not mean that is then OK to land overweight, it means that if the actual trip burn is not achieved such that an overweight landing would otherwise appear likely then the burn should be adjusted by whatever method is appropriate (holding ?) to land at the MLW or less.

From what you say, it appears that you are substituting items (B+C) for item (B) only in your loadsheet preparation ? If so this is not correct. I can see how increasing the trip fuel on a MLW restricted plan would allow for an increased payload, and provided the fuel is actually used ( by whatever method) there is no problem with that in theory, however landing overweight is not a naturally allowable consequence of such a practice and I am surprised this is being done regularly and not being detected by reference to the tech log fuel arrival figures etc ? If this is the case then the problem lies more in the violations that are happening when you exceed the actual certified landing weight rather than what was shown on the loadsheet as trip fuel.
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