Rules of the Air — Page 126, Lesson 206

I want to walk you through the visual warning signals that keep aircraft safe around restricted airspace and aerodromes. Let's start with the incursion warning. By day and by night, there's a specific pyrotechnic signal used to warn you that you're flying in, or about to enter, restricted, prohibited, or danger areas. It's a series of projectiles discharged from the ground at intervals of 10 seconds. Each projectile, on bursting, shows red and green lights or stars. So if you see red and green star-shell pyrotechnics, that's the universal warning that you're about to enter a restricted area or an active danger area. The 10-second interval is important — that's the cadence you're looking for, not just a single burst. Now let's move to signals for aerodrome traffic. There's a category of traffic called non-radio traffic — aircraft without radios operating on or in the vicinity of an aerodrome. They must keep a good lookout for visual signals from ATC. But here's the key point: aeroplanes with radios are also required to comply with instructions given visually. So even if you have a radio, you still obey the light signals. The lamp ATC uses to communicate is called the Aldis lamp. It's directional with a narrow beam. That means the signal is aimed specifically at you. So if you see a signal light from the tower, you must assume it's meant for you — not for another aircraft. Now, the visual signals themselves. These are light and pyrotechnic signals used from ground to air. Let me walk you through the table, because this is the core of what you need to know. From Aerodrome Control to aircraft in flight: A steady green light means "Cleared to land." A steady red light means "Give way to other aircraft and continue circling." Green flashes mean "Return for landing and await landing clearance." Red flashes mean "Aerodrome unsafe, do not land." White flashes mean "Land at this aerodrome after receiving clearance to land and then proceed to the apron." And a red pyrotechnic flare means — notwithstanding any previous instructions — "Do not land for the time being." Now from Aerodrome Control to aircraft on the ground: A steady green light means "Cleared for take-off." A steady red light means "Stop." Green flashes mean "Cleared to taxi." Red flashes mean "Taxi clear of the landing area." White flashes mean "Return to the starting point on the aerodrome." Notice the contrasts here. Steady green is the positive clearance — land in the air, take off on the ground. Steady red is the stop signal — circle in the air, stop on the ground. Flashes modify the meaning: green flashes are about movement — return for landing in the air, taxi on the ground. Red flashes are about danger — don't land in the air, clear the landing area on the ground. White flashes always direct you to a specific place — the apron in the air, the starting point on the ground. And the red flare overrides everything — it's the absolute "do not land" signal regardless of what you were previously told. That's the complete set of visual signals. The key takeaway is that these are mandatory — even with a radio, you comply with them, and you assume any light from the tower is directed at you.