We say daft as aircraft prefer to land on level runways and taxi on level taxiways. To accommodate a rise or drop of 8 metres will require a greatly extended circular gentle gradient riser access to the new runway above.
The Times reporting an old industry chestnut, are suggesting the new Heathrow runway will be raised some 8 metres above the existing motorway interchange, leaving the existing road network well alone and the M25 runway 'bridge' section put in place at the last minute.
Harmondsworth village however apart from the pub, a church and a few properties will be raised to the ground, as most of it will be within the new airport perimeter, if not actually under the runway itself. We say this is an old chestnut, as the first above the houses idea was mooted in the 1950's for an imaginative runway 'X' scheme over Kings Cross railway station.
The idea to leave the M25 alone and just build over and effectively around it, won't work unless there are permanent water pumping stations in place, just as they operate in Holland, to deal with water run off during wet weather and at all other times as the water table along the entire length of the new runway and surrounding aprons will be unnaturally depressed.
The water will have to run off somewhere and that would seem to be the unintentional reservoir being created by the M25 bridging plan for the new runway. The water NATURALLY finding its own level, will run off to the gridlocked M25 motorway network below the proposed runway.
Cast your mind back to the Wimbledon tennis championships when a flash cloudburst and flood dramatically filled pedestrian tunnels as Cliff Richard sang to the waterlogged spectators above....
It is already known that Heathrow will be installing a covered levy network to convey floodwater run off to areas surrounding metropolitan London with the result that residential property some fifty miles away, which to date has been free of flood incidents, will now find their properties drop substantially in value, as they are suddenly in a flood risk area, only revealed when the Environment Agency get around to updating the flood risk maps or sewage seeps over the doorstep.
Fort Lauderdale Airport is held up as being near to the Heathrow elevated runway concept. We cannot see it, what do you think?
JULIAN BRAY +44(0)1733 345581 Aerospace & Incident Management Expert, Journalist & Broadcaster, Aviation Security & Airline Operations, Travel / Maritime & Cruise Industry, NUJ, EQUITY, LIVE ISDN LINK, Broadcast ISDN COOBE ++44 (0)1733 345020 e&oe Old faithful NOKIA: 07944 217476 www.aviationcomment.com