Old Smokey,
.. I really want to make a politically incorrect and inappropriate comment .. but I mustn't .....
To address the real obstacles, one puts enough dummy obstacles in between the intersections (and especially after the final intersection) to suit matching the AFM gradients to the polygon thereby forcing the net flight path to stay about the polygon. These dummy obstacles are defined to lie along the relevant polygon surface .. so the discrete obstacle program is forced not to dip below the surface .. QED no fly into ground problem.
End result is no less "safe" than matching gradients but, especially for close-in obstacles, .. is far less conservative and may produce significant RTOW benefits .. not always, but, for small close-in obstructions, the benefits can be quite significant .. all a case of horse for courses.
Not flying these days, I don't have to rush off on multiday tours .. as a good little contractor, I just have to work 24/7 except for the occasional day off every 3 years for good behaviour ... I miss the flying .. but c'est la vie ... might have to go do a circuit or two sometime and see if I can still stay right side up....
Mk VIII,
Think EOL = STODA .. just a name change. You may have a different definition for some specific purpose, but the old AIP usage was equivalent to STODA - if there is any difference, I am not aware of it and it would be fairly subtle .. perhaps Overrun can comment if he is following this thread ?
TORA has nothing to do with STODA. TORA is there solely to constrain clearway for the TODA case.
The airport authority declares an available clearway but, in many cases, a given aircraft can't use it all ... reason being that we need to make sure that the bird is off the ground before it runs out of seal and into the dirt .. recall that clearway can extend a significant way beyond the end of the runway. Depending on the rules applicable to the operation, only 2/3 or 1/2 of the airborne distance from liftoff to screen may be over the clearway. This restriction is built into the TORR calculation.
In the STODA case, the TORR-limiting calculation ceases to be limiting at all as the available TOD (STODA) is less than the declared TORA. Reflect upon the picture ... TORA is fixed by the physical runway dimensions. For TOD calcs based on STODA the actual TOR will reduce but this has naught to do with TORA
Questions is what questions forum is all about ...
regards both,
JT
Last edited by john_tullamarine; 12th Feb 2005 at 12:41.