Definition
A continuous, non-flashing green light signal directed at an aircraft from the control tower's light gun. To an aircraft in flight, it means cleared to land. To an aircraft on the ground, it means cleared for takeoff.
Plain English
An unbroken green light shone at your aircraft from the tower. If you are flying, it means you may land. If you are on the ground, it means you may take off.
Context Anchor
Seen in lost radio communication procedures, when a control tower uses colored light signals to communicate with an aircraft.
Derivation
“Steady” comes from the idea of something firm or fixed. In this signal, it helps you remember that the light is continuous, not blinking. “Green” is commonly used to show permission to proceed, but the exact aviation meaning depends on whether the aircraft is on the ground or in the air.
Why Pilots Care
It gives pilots a clear visual clearance to continue landing or departing safely when radio communications have failed.
Intuition Check
Do not read steady green as simply “green means go” in every situation. On the ground it means cleared for takeoff; in flight it means cleared to land.
Example Sentence 1
With his radio out, the pilot circled the field until the tower gave him a steady green and he turned final to land.
Example Sentence 2
On the runway the tower showed a steady green light so the pilot began the takeoff.