SS,
Not sure now if you're deliberately mixing my points up.
2 min wake turbulence separation applies on departure (assuming all full length departures) between:
J followed by H,
H followed by M/S/L
M/S followed by L;
3 minutes applies between;
J followed by M/S/L
Completely separate from that;
Route separation on departure (assuming same wake category) applies as follows at LHR
1 min: Routes diverge by 45 degrees or more
2 min: Similar/same route. For those that diverge, but less than 45 degrees, with the approval of the CAA and because we are qualified for advanced use of the ATM, we can reduce that to 5nm spacing.
The above are modified depending upon relative speeds.
Therefore, I was making the point that with all your SIDs going straight ahead to 5nm, all departures would be subject to 2 minute separation. Perhaps a more stringent MDI would apply to some routes due to their interaction with other London airports or LACC/French/Belgian/Dutch sectors (as it is at LHR with DVR followed by DVR) which might be 3 minutes. Perhaps we could argue that some combinations of routes may be reduced to 5nm, but that's best case. With all SIDs going straight ahead to 5nm, you will never get 1 minute separations.
Regarding CAT IIIb approach landing clearances at 1nm, that's a regular feature at LHR. With 6nm spacing on a dedicated landing runway, in 'normal' CATIII conditions, the one ahead of you will only be vacating the LSA (137m from the runway centreline) when you pass 2nm. If they are slower than usual for any reason, the 1nm point is the cut off. What is your decision height on a CATIIIb approach? Are you getting mixed up with the ILS
sensitive areas and the ILS c
ritical areas? We give landing clearance in CATIII conditions as soon as the
sensitive areas are clear, which as I said can be as late as 1nm from touchdown.
Geffen,
Thanks.......
Maybe we should put this down as Project Y???
