ATC light signals.
ATC light signals have the meaning shown in the following table:
Color and type of signal
Meaning with respect to aircraft on the surface
Meaning with respect to aircraft in flight
Cleared for takeoff
Cleared to land.
Cleared to taxi
Return for landing (to be followed by steady green at proper time).
Give way to other aircraft and continue circling.
Taxi clear of runway in use
Airport unsafe—do not land.
Return to starting point on airport
Alternating red and green
Exercise extreme caution
Exercise extreme caution.