Differing approach directions: Heathrow & City?

[davethelimey]

I've noticed that sometimes planes will be heading for Heathrow heading westwards, while those heading for City are approaching eastwards. Surely the winds can't be different for two runways that close together?

[HEATHROW DIRECTOR]

It's probably a case of Heathrow on preferential westerlies and City following the wind. To appease the noise freaks Heathrow sometimes operates with a downwind component..

[ATCO Two]

Hi Dave,

As HD says, Heathrow continue to operate on Westerlies with a 5 knot tailwind component. Also there are many occasions when the wind direction varies markedly between the two airports; I do not know the meteorological reason for this, but it is just a fact of life. Furthermore, some companies at City cannot even accept 1 knot of tailwind component, given the limited runway dimensions. It is a regular occurrence on days when the wind is variable to change the runway in use at City in the middle of an inbound sequence. Hope this helps.

[brimstone]

dave - On days when there is a slack pressure gradient there can often be a sea breeze which travels along the Thames quite a long way inland. This can give different wind directions at the two airports, an easterly at London City affected by the sea breeze and any other direction at Heathrow in accordance with the pressure pattern.

[RomeoTangoFoxtrotMike]

HD/ATCO2

As a matter of interest, in these circumstances, would ATC be passing "traffic info" on each aircraft to the other, or are pilots happy to assume that they are separated unless the TCAS goes off ?

Thanks,

/RTFM

(from his vantage point under the approach to runway 10 of EGLC)

[HEATHROW DIRECTOR]

All traffic to City and Heathrow is automatically separated by the procedures employed so no traffic information is passed. Full IFR separation exists and it is the responsibility of the controllers directing City traffic to get down under the Heathrow ILS. Equally, those controlling Heathrow traffic must not descend below certain altitudes at particular points to ensure separation.

Full IFR separation exists at all times.

Hope that's OK..

[RomeoTangoFoxtrotMike]

Full IFR separation exists at all times.

I had no doubt that it didn't

I was just curious to know if, for example, the first thing a Heathrow inbound on a westerly would know about the EGLC inbound on an easterly passing underneath him would be if his TCAS mentioned it, or whether he would be advised of this by ATC... not worried, just terminally curious

[HEATHROW DIRECTOR]

OK.. He might see it on TCAS but ATC does not pass traffic info if the traffic is properly separated.. I worked those Heathrow inbounds for many, many years and never once found reason to pass traffic info on City traffic. Equally, traffic info is not passed on the light a/c and helicopters passing under Heathrow inbounds.

[Gonzo]

Equally, traffic info is not passed on the light a/c and helicopters passing under Heathrow inbounds.

Sometimes the tower needs to reassure inbounds on the ILS that the "Traffic Traffic" alert on the TCAS is because the helicopter flying underneath him isn't squawking mode C and IS separated by more than 1000 feet.