Mutt,
Thanks for those gradients - exactly what I was looking for.
Makes me wonder how well we manage community relationships. Historically, when aircraft performance is discussed with town planners and local councils, the only response we can give is about engine-out performance and obstacle clearance gradients. This conjures up images in the lay mind of aircraft screaming above the treetops on one engine, with flames pouring out of the other. The reality as we know is quite different - in normal operations, aircraft climb out smartly and are soon well above the obstacles.
For what it's worth, I've started handling such discussions by using the concept that there is a "buffer zone". Something like this:
the obstacle clearance gradients are there to establish a buffer zone between the aircraft and any obstacles. In normal operations, the aircraft flies well above this but the buffer zone provides the necessary margin of safety for all conditions. It takes the emotion out, and makes for a more productive discussion [too late for Sydney Airport though
].
john-tullamarine
Thanks for the suggested method of calculation. I haven't got the AFM or crew manuals (being neither management nor closely aligned), and TOR2 and TOD2 have got me a bit stumped
- are these TORA and TODA or something more refined? I got my data from the full performance calculations by the Eagle, Takeoff Weight and other QF and AN Ops programmes.
If you have the chance to while away some time in DJ cruise (as an alternative to the face painting) and look at the two cases, I'd appreciate it and would indeed owe you a frosty or two. Zero wind and assuming all other factors neutral is fine.
OverRun