Third Runway’s Flight Paths

It is becoming clearer where the flight paths may be if a third runway is built.  HeathrowAirport commissioned a report, Air and Ground Noise Assessment01: Air and ground noise assessment – from AMEC which includes an assessment of the new flight paths.

The report includes interesting options for respite (which could be implemented with a two runway airport and which are detailed below) but it is the arrangements for new flight paths which will be of most interest to people closer to the airport.

Hammered by a Third Runway

A third runway will be to the north of the current northern runway.  It will be built between the A4 and the M4.  In its report AMEC says that planes will need to be lined up with the new runway around five miles from the airport. Areas within these last five miles that can expect a plane overhead, one every 90 seconds, between 6am and 11pm, with a break of just over 4 hours.  Places in the firing line include Sipson, Harlington, Heston, Norwood Green as well as the areas of Brentford close to the M4.  Areas beyond the five mile joining point, like BedfordPark and Hammersmith, will also feel the impact.  To the west of the airport places like Langley and Eton will be hardest hit.

Runway Alternation to be cut by Half

At present people in West London enjoy a half day’s break from the noise when planes landing at Heathrow switch runways at 3pm.  This will change if a third runway is built.  For some people this will be cut to just over 4 hours.

How the flight paths will work if a third runway is built


  • Planes will land on the new runway for 12-13 hours a day
  • Planes will land on the current northern runway for 6-7 hours a day
  • Planes will land on the current southern runway for 12-13 hours a day

Places like Kew or Hounslow West under the northern runway will continue to get around 8 hours of respite but this will be off-set for many because they will be able to hear aircraft from one of the two other runways.  For places like Richmond under the southern flight path the respite period will be cut from 8 hours to just over 4.

A similar system of respite will apply when planes land from the west

The same system will also be introduced for take-offs to allow periods of respite for communities within a few miles of the airport

Periods of Respite

A greater sharing out of flight paths than now can take place will be possible beyond about 5 miles from the airport; that is about as far as Windsor to the west and Isleworth to the east.  And, on departure, it will become possible 3 miles out from the airport.  This change is made possible by the new technology which can guide planes much more precisely.  Aircraft will not need to join their final approach path until about 5 miles from the airport.  At present they are required to join it much further out and can be lining up with the runway over 25 miles from the airport.  It is this long concentrated approach that has brought misery to so many.  HACAN has done surveys which show there can be over 40 planes an hour passing over the Oval or Clapham at heights of around 3,500 feet.  Places, like Peckham or Brockley, even further east, are equally plagued by this constant noise.  The same applies to people living west of the airport.   If the joining point was only 5 miles from the airport, it would allow the planes to fan in from different angles, both sharing out the noise and allowing everybody some respite from it. However, it cannot be said strongly enough that this sharing out of flight paths, is not dependent on a third runway being built.

This briefing has been produced by HACAN, a voice for residents under the Heathrow flight paths.  We can be contacted at 13 Stockwell Road, London SW9 9AU; email; tel 0208876 045                           August 2014