Bik
Another cogent post as we're coming to expect, but let's put all this into perspective.
TCAS is great - no question, I think that all pilots have come to find it to be one of the most important pieces of kit at their disposal. However, from the view of a safety regulatory point of view (and I'm only playing Devil's Advocate here), a 4 way RA does not, at the outset of conflict resolution in the planning phase, have any degree of inherent, built in separation. I'm not saying that it is not safe, as I think we have established TCAS IS safe, but it cannot form the basis of a separation mechanism on it's own because you cannot show, AT THE MOMENT, any pro active, pre planned separation, only a tactical phase resolution. The TCAS separation is purely reactive. I'm sure this bothers safety regualtors and operators alike.
But there are projects in place to investigate the use of Mode S information to couple with TCAS that could eventually mean that it WILL be integrated into actual input in separation. Mode S can provide information on the data block on the radar to show selected level, selected rate of climb/descent and, perhaps, TCAS RA and it's order of direction.
Now, remeber when we were talking about ATCOs becoming system managers Bik, a couple of weeks ago? Well, let's extrapolate that idea.
On the flight deck, pilots get the ATC cleared level, select the relevant level and relative rate of climb descent. The controller/monitor bod is watching all this info via Mod S, can see an incorrect level selection and correct it, can spot a potentially excessive RoD/C and rectify (not necessarly instruct to change but point out that it may be excessive, fter all you fly the planes!)and in the event of TCAS RA, and I believe that this one should be implemented ASAP to stop a rerun of Lake Constance, a controller will be able to observe the RAs given to each aircraft and leave well alone unitl the Mode S shows the event to be over. Most imnportantly, there will never be the need for a controller to give contradictory avoiding action in the event of TCAS RAs ever again because the whole scenario will be displayed on their screen.
These are huge leaps forward in technology led safety and form an interesting future. And for all those out there who say "What if the cleaner knocks the plug out?", then we revert to the system we have now, same as if someone pulls the plug now we go
procedural etc.
Today's best practice is tomorrow's back up plan.
P7
Post Script
The P-RNAV arrival at Heathrow is being developed so that British airlines can prove the system works in practise, then devise their own procedured into airfields with poor ATC service and/or poor or unserviceable nav aids. It will also provide quieter CDAs so that night quotas can rise but the public can be shown that they're not getting a raw deal. Maybe.
