Methodology

Operational reporting draws on published operations briefings, works notices, slot coordination circulars, airspace change consultations and airport consultative committee papers. Where a figure comes from a model rather than a measurement, such as a noise contour, we say which and describe the inputs that moved.

Delay reporting is based on attribution codes rather than complaint volumes, because the two describe different things. Capacity figures are quoted with the time of day they apply to, since an airport almost never has a single capacity number.