Night-time rotation
In 1999 the runway alternation scheme was extended to the night period and – at night only – for easterly operations.
There is a weekly rotation of westerly and easterly arrivals after the last departure until 06:00, subject to weather conditions on any particular night.
This has resulted in a more even split between westerly and easterly operations than the previous figure of nearly 90% of early morning arrivals overflying London in an average year at Heathrow.
