when/why are runways at LHR switched

[spannersatcx]

I know nothing about LHR.

I had an e-mail from my brother-in-law who is a photographer, recently he has taken an interest in aircraft and has made several visits to LHR.

He says at 1500 the runways are switched at LHR from say landing on 27L to landing on 27R. I said it may be something to do with noise abaitment.

Does anyone know if in fact they do switch runways at a set time and why?

[SMOC]

You are correct.

Runway alternation is a system introduced at Heathrow Airport to alleviate noise disturbance experienced by local residents affected by arriving aircraft on the final approach to land. Its principal advantage is that it provides certainty of periods of relief from aircraft noise for local communities.

During the day, on westerly operations, one runway is used for landings from 07:00 to 15:00 and the other from 15:00 until after the last departure. This arrangement runs for a week from Monday to Sunday and the order is reversed every week. Due to the Cranford Agreement, there is no daytime runway alternation during easterly operations.

At night there is runway alternation on both westerly and easterly operations after the last departure until 06:00. It begins after the last departure in order to coincide with the rotation of the westerly/easterly preference at night. (See direction of operation).

http://www.heathrowairport.com/portal/controller/dispatcher.jsp?CiID=e31bc03b37932010VgnVCM100000147e120a____&CtID=448c6a4c7f1b0010VgnVCM200000357e120a____&Ct=B2C_CT_GENERAL&RootCh=About%20BAA%20Heathrow&Ch=Runway+Alternation&ChID=64ce1fb079432010VgnVCM100000147e120a____&ChPath=LHR%5EAbout+BAA+Heathrow%5ECommunity+matters%5EAircra ft+Noise%5ERunway+Alternation&ChIDPath=bde597dc2eb12010VgnVCM100000147e120a____%5E815797dc 2eb12010VgnVCM100000147e120a____%5E06cd1fb079432010VgnVCM100 000147e120a____%5E548e1fb079432010VgnVCM100000147e120a____%5 E64ce1fb079432010VgnVCM100000147e120a____

[spannersatcx]

Thanks SMOC, that should keep him happy.:ok: