What does a steady green light signal indicate when on the ground?

A steady green light signal when on the ground indicates that an aircraft is clear for takeoff. This signal is part of the air traffic control visual communication system, which pilots must understand to ensure safe operations.

When a pilot sees a steady green light at the runway threshold, it confirms that the runway is clear, and they have been granted permission to commence takeoff. This is crucial for maintaining safety and proper coordination between pilots and air traffic controllers in busy airport environments.

Alternatives include signals such as a steady red light, which typically indicates that an aircraft must stop, or a flashing light, which signals the need for caution. The clarity of the green light communication helps avoid confusion and assists pilots in following the established procedures for safe aircraft operations and transitions on the ground.