What process should be confirmed before indicating an aircraft is ready to tow?

Before an aircraft is indicated as ready to tow, it is essential to ensure that the external doors are closed and the airstair is retracted. This is critical for safety reasons, as any open door can pose significant risks during towing operations, including the potential for accidents or unintended access to the aircraft. Ensuring that external doors are secure protects personnel on the ramp and prevents any interference with the towing vehicle or the aircraft itself.

Proper preparation of the aircraft also includes checking that no persons are in the vicinity of open doors and that the airstair is positioned correctly. This step is fundamental to maintaining safety protocols during towing operations and is an essential part of the procedural checklist that ground crew must follow. Inadequate preparation can lead to operational issues or safety hazards.

The other options, while also important for various reasons in different contexts, do not directly align with the specific requirement for confirming aircraft readiness for towing.