Flight planning... Hardest exam ever.
The "10" you speak of is a guessdimation on what you think the fuel burn will be per nm in that given situation. Another name for this is the Specific Ground Range.
Nathan says a headwind of 50kts would increase your estimated SGR by 1 and a 50kt tailwind would reduce it by 1.
However this is dependent on the situation. If the distance was less than say 300 I'd just stick to 10.
All this is used for to to work out an estimated fuel flow.
Once you have your fuel flow for that leg, half it and subtract that from your gross weight to see if it matches your estimated fuel flow.
If it does then move on.
Flight planning is a headache even to study and the way CASA construct their exam is crazy! 4 hours of work required to be done within 3... Good luck!
Last edited by dabz; 10th Sep 2012 at 06:31.