Alex, Thanks for the explanation, but I still don't think that its sufficient to explain the use of LHR Rwy09 in summer. There are 6 principle air masses which influence the British Isles, the Polar Continental one will primarily give a wind direction which favors 09, however this airmass usually occurs in the winter. The more common airmasses during the summer will produce airmasses moving from Southern Europe or the Atlantic, none of which can guarantee easterly winds. The we have the Polar Front which usually sits between Newfoundland and Scotland during the summer, this front usually follows a curved path across the Atlantic into Europe and produces westerly winds. I fully accept that the runway in use is based on wind direction but associating the use of RWY09 with the summer rather than the winter still confuses me. Cheers. ----- Original Message ----- From: "Alex Nieves" <alexnieves1@juno.com> To: <AIRLINE@LISTSERV.CUNY.EDU>; <smurf@zajil.net> Sent: Thursday, February 07, 2002 3:49 PM Subject: Re: In defence of Heathrow > Runway selection is based on wind. Usually, the main runways airports > use are where the prevailing winds are found most days of the year (a lot > of research goes into prevailing winds and winds in general at airports > before runways are built). Some airports, however, have the winds change > seasonally...in winter, winds are from one direction and in summer, > they're from another. And there are some airports that hardly ever > change. Example of an airport where the winds are usually the same all > year long is San Juan. It is rare to see planes taking off on Runway 26 > and 28. Hopefully I explained it simply and that it satisfies your > question....I can explain it in a longer version if you have problems > understanding this version, so let me know. > > Alex Nieves > > On Thu, 7 Feb 2002 15:28:33 +0300 Smurf <smurf@zajil.net> writes: > > I always thought that the runway selections were based on wind > > direction and > > not seasonal. Therefore the fact that its summer or winter shouldn't > > have > > any bearing on when Rwy09 is in use..... Or is LHR different to the > > rest of > > the world? > > > > Cheers > > > > Mutt. > > > > > > ----- Original Message ----- > > From: "Jim Fulton" <jim.fulton@talk21.com> > > Sent: Wednesday, February 06, 2002 2:46 AM > > Subject: FW: In defence of Heathrow > > > > > > > Chris, > > > > > > Most of the year LHR runways in use are 27L & 27R, but in summer > > 09L & 09R > > > are sometimes in use. The designated area is on top of the > > Queen's > > Building, > > > which is OK in June as the sun is high and it overlooks terminal 2 > > and a > > > distant terminal 4, though a fair bit of traffic passes by. You'll > > need > > > binoculars for spotting, and up to a 300mm lens for taxiway > > shots. > > > > > > > > > Alex > >