Flight routes

Aircraft landing over our Borough line up with the runway as far away as Greenwich using the ILS (Instrument Landing System). This is soon to be changed to the MLS (microwave landing system). By the time they reach Wandsworth, they are roughly at 3000 feet and then glide down on a 3 degree glide path to the runway (a descent of approximately 300ft per nautical mile). If this is done carefully using a low power/low drag approach (LP/LDA) and in a continuous descent approach (CDA), it reduces the noise.

Heathrow are trying to encourage more and more airlines to adopt this procedure. In 2001 they reported that approximately 90% of all airlines were now using it on their approach to Heathrow. It has only slight benefit to Richmond residents as most aircraft are already on the glide slope when they are over the borough.

Runway alternation

‘Runway alternation’ is employed every day at Heathrow. It has the effect of giving either morning or afternoon respite to the communities between London and Heathrow. The switch over occurs at 3pm, when e.g. aircraft coming in to land to the southern runway will be directed to switch over and come in instead on the northern runway. The result of this switch over is to give some much valued relief for the half day period that they are not overhead.

BAA has published its alternation programme for year 2011. It shows which runway is designated for use, when the wind is westerly – which is the prevailing wind for 70% of the year. Westerly arrivals are those aircraft flying towards Heathrow, from the London direction.  At present there is no alternation for the other 30%, when the aircraft take off towards London. However, this will change in a couple of years, when Heathrow has built some new taxi ways – following the cancellation of the ‘Cranford Agreement’.

The BAA programme shows that the night time alternation arrangement is more complex, as it involves the Sunday to Monday switch over, plus a night time rotation arrangement, to share the noise between the four approach routes to Heathrow. This programme can again be changed if e.g. a strong wind comes from the ‘wrong’ direction.

The Government has now approved a ‘freedom trial’ to take place at Heathrow, starting on 1 November 2011.  In pursuit of various benefits, the trial will have the unfortunate effect of disrupting the anticipated respite. Instead of enjoying long periods of noise relief, it is expected that there will be an increasing number of periods when aircraft will be flying on the wrong flight path. The Council understands the community concern about this.  Although the published alternation programme itself will not be affected, it is the anticipated additional flights on the ‘wrong flight path’ that are causing the concern.

The Council welcomes the Government’s recent commitment to retain runway alternation at Heathrow and that there will be no increase in the number of flights, which will remain capped at current levels.

The Cranford Agreement

In the decision of 15 January 2009, the Government announced that the Cranford Agreement was to end. This means that there will be some changes to five easterly take off routes over the borough, as aircraft will soon be allowed to fully use the northern runways. Although the take off routes already exist, they have almost never been used. No date has been fixed for using the northern runway full time on easterlies, as there are still some taxi way improvements to make before it happens.