Which conditions are required to cause the green towing light on the nose gear to illuminate?

• A. Steering disengaged only
• B. Parking brake not set only
• C. Toe brakes not applied only
• D. Steering disengaged, and parking brake not set or toe brakes not applied

Answer: (D)

The green towing light signals that the aircraft is safe to tow on the ground. For it to illuminate, the nose gear steering must be disengaged so the tow tractor can guide the nose wheel without conflict with active steering, and the braking system must not be engaged—meaning the parking brake is released and toe brakes are not applied—so there’s no brake drag or locked wheels during towing. If steering is still engaged, or a brake is applied (parking brake set or toe brakes pressed), towing isn’t safe, and the light won’t come on. That’s why the best answer combines steering disengagement with the brakes not being engaged.