Hi pudoc.
I appreciate what you're saying. I have scrutinized it to death now and cannot improve on my accuracy. More worryingly, if I work this in the "forward" sense using their weight of 3530 lb I derive a take of distance (no factors applied) of 2700'.
Here's a talk through on what I'm doing just in case I've cocked up! On the right of the graph the boxes are in increments of 100 so I enter at one block above 2500. Paralleling down to the ref line and left across to a 10kt headwind as accurately as I can, then up a short slope to that ref line - and I'm happy with the accuracy having used these graphs umpteen times before.
Next its a straight line across the mass grid which I have drawn absolutely straight. Now the fun begins; using their already plotted data (PA 5653' OAT 15C) I drift down to intersect my line at precisely 3430! Very confusing and frustrating isn't it?
Afternoon FlyingStone. Not sure what you mean, if I'm honest, about the question bank since this is a worked as example as provided in the CAP itself. I agree about natural variations but its quite a bit on this one plus I'm thinking that since they got 3530 and I got 3430 there is some silliness going on.
Last edited by StatorVane; 2nd June 2012 at 14:16.