I did a flight to Turkey last night, and whilst sitting there in the dark in the FL300's I watched (for nearly an hour) what could at best be described as an unerringly accurate 'line-astern' formation being kept by the four aircraft in front of us - it was a visually fabulous example the accuracy of IRS (and GPS) navigation.
I too have to agree about including an 'offset' in as much that it surely can't hurt - albeit that some earlier version FMC's don't support this function.
But how about also turning 'right' (as we used to) when you get a TCAS RA ? The point being that if TCAS has determined that a line-of-constant-bearing (LOCB) exists between two aircraft and as such there is a risk of collision - which it attempts to resolve by telling one aircraft to descend and the other to climb, so providing vertical separation - it has not resolved the fact that both aircraft are still on a line-of-constant-bearing from one another, i.e. get an RA in clear skies, you descend, the other fella climbs, you might very well find that the other aircraft goes literally right over your head - chilling stuff !
So why not also attempt to break the line-of-constant-bearing - by having both aircraft turn as well as also comply vertically with any TCAS RA instruction ? Surely the logic for this could be built into the TCAS software ( and one would imagine that modern computer processors should be more than able to cope with doing the maths ) and thus as well as having the vertical separation you'd also hopefully be breaking the LOCB by having the TCAS co-ordinate 'roll' guidance to the Flight Director(s) on each aircraft - and whilst we wait for such a mod to be actioned why not have a SOP that dictates that in the event of an RA climb or descent you should also turn right by (say) 45 degrees ?
Uhm, now would this have helped over Germany, e.g. if the B757 had not only been descending, according to its RA, but also turning 'right' ? Well at least it would have been trying to break the LOCB and they might have then missed each other, though maybe not by much - but a miss is a s good as a mile.
Of course I'll admit that adding extra functionality to the TCAS logic will cost money (i.e. lots), but what price does one put on the lives of an aircraft full of children ?
Ah well, it's just a thought, any takers ?
Last edited by Devils Advocate; 6th Jul 2002 at 11:12.