When does the controller raise the safety bar on the boarding platform?

The correct answer is that the controller raises the safety bar on the boarding platform after the flyers are standing on the platform but before disconnecting from flight cables. This procedure is critical for maintaining the safety and security of the flyers as they prepare for their ride. By raising the safety bar only when the flyers are securely on the platform, it ensures they are properly positioned and ready for the experience. The safety bar serves as a protective barrier that helps to secure the flyers in place and is an essential part of the safety protocol to prevent any accidental falls or injuries during the transition from the ground to the flight phase.

Raising the safety bar before the flyers are on the platform could create unnecessary risks, as there would be no one to secure. Disconnecting from the flight cables before the bar is raised can also pose safety hazards since it may leave the flyers without sufficient protection during this critical moment. Lastly, raising the bar while the flyers are descending would not be appropriate, as it would go against the protocol of ensuring flyers are safely secured before any movement begins. Therefore, the timing of the safety bar's operation is crucial for ensuring a safe experience for all participants.