What is the purpose of down-lock indicators on landing gear?

• A. Confirm the gear has begun to extend.
• B. Confirm the gear is down and locked.
• C. Confirm the doors are closed.
• D. Confirm no fault codes on the gear system.

Answer: (B)

Down-lock indicators provide a positive confirmation that the landing gear has reached its full down position and that the down-locks are engaged. This is crucial because once the gear is locked down, it cannot retract during landing, keeping the aircraft safely equipped for touchdown. The indicator is about mechanical readiness of the gear in the extended position, not just that it’s begun to move.

This isn’t about door status, and it isn’t a fault-code check. Doors have their own indicators, and fault codes are part of a separate system health check. So the down-lock indicator specifically verifies that the gear is down and locked, giving the crew a clear, reliable signal that the gear is in a safe configuration for landing.