SS,
** With runways that close together, departing aircraft lining up on the inner runway will be within the ILS protected area for the aircraft on a CAT III approach to the outer runway. Thus no low-vis departures can be made from this airport, while aircraft are approaching, or vice versa. Is that mad, or what?
Sorry? Assuming we take that the artist's impression as a fixed blueprint (??), the LSA for CAT III ILS only has to be protected for landing clearance when the landing clearance is given, normally at 2nm, exceptionally at 1nm, so that''s not true. If you get confirmation that the departure is not using LLZ guidance, then you don't have to protect the LSA at all for departures.
You also claim:
Is forced to delay outbounds (on the inners), to wait for inbounds (on the outers) to cross the runway,
Ever heard of wake turbulence separation? 2 minutes?
But then in your masterplan;
Departures would then either:
a. Carry straight on between Gillingham and Gravesend.
b. Turn left 180 at 5nm and pass between Sittingbourne and Gillingham.
b. Turn right 270 at 5nm, and track to East tilbury, before turning north up the Basildon Brentwood gap.
So if all departures go straight ahead to 5nm, then
every single departure would be a minimum of 2 minutes separation behind the last. As I'm sure you know, the ICAO regulations in SOIR DOC9643 say that simultaneous departures from parallel runways should diverge
immediately after take off. Also, good luck on trying to make sure that the southbound aircraft from the 'commuter runway' don't get in the way of the west and northbound aircraft from the other two runways! At the end of the day, I don't think looking at that you'd have any more capacity from your plan than we do in theory from LHR! With two extra runways! What a waste of money!