What must a pilot do when clearing the reverse signal associated with the interlocking?

When clearing the reverse signal associated with the interlocking, the pilot must call clear of the interlocking. This action is vital because it ensures that the operating staff is informed and confirms that the interlocking is safely and properly cleared, allowing for the safe movement of the train. The phrase "call clear" implies that the pilot must communicate this status, which is crucial for maintaining safety protocols and coordinating actions among the crew.

While notifying the conductor, checking weather conditions, and securing the train are important responsibilities in their own rights, they do not specifically relate to the immediate action required when clearing the reverse signal at interlocking. Clearing signals and ensuring operational safety require proper communication, and calling clear enhances the safety and efficiency of train operations.