VFR
Light signals from the control tower
To aircraft in flight
- Steady green: cleared to land.
- Flashing green: return for landing (expect a landing clearance).
- Steady red: give way to other aircraft and continue circling.
- Flashing red: aerodrome unsafe — do not land.
- Flashing white: land at this aerodrome and proceed to the apron.
- Series of red pyrotechnic lights: notwithstanding any previous instructions, do not land for the time being.
To aircraft on the ground
- Steady green: cleared for take-off.
- Flashing green: cleared to taxi.
- Steady red: stop.
- Flashing red: taxi clear of the landing area in use.
- Flashing white: return to the starting point on the aerodrome.
Source: SERA Appendix 1 – Signals