Don,
Heathrow is not the most congested airport in the world. The London TMA and surrounding area however is the most congested airspace in the world (according to figures published earlier this year).
See the thread in this section entitled:
Pilot/ATC Courses at LATCC (TC)
Arrange to come along on one and begin to understand how the whole ATC system in the SE of England works. Feedback from previous courses is excellent. Hope to see you there!
You will then hopefully understand that in an IFR environment, the same amount of traffic is moved per hour whatever the weather (unless we are in low vis procedures).
The main factor affecting the landing rate is the wind speed and direction along the final approach track and down to the ground. Over the past few days (despite the CAVOK and sun), the wind conditions have been average, and therefore so has the landing rate.
Cheers,
AI
[This message has been edited by Aluminium Importer (edited 25 May 2001).]