What does the AC check while on the rolling boarding platform?

The correct answer highlights a critical safety procedure performed by the attendant controller (AC) during the boarding phase of a Skycoaster experience. When on the rolling boarding platform, the AC is responsible for checking the backstraps, buckles, and legs of the harness system for each participant. This step is essential to ensure that all riders are securely fastened and that their harnesses are properly adjusted to prevent any risk of falling or injury during the flight.

Ensuring that backstraps are secure and that buckles are properly locked is vital for the safety of the riders. The AC also checks that the leg straps are correctly positioned and fastened because they help to further secure the riders in the harness and provide additional support during the ride. This meticulous attention to safety helps give riders confidence and contributes to a safe and enjoyable experience.

While the other choices involve important aspects of the Skycoaster operation, they are not the focus of the AC's checks during this specific stage. Launch cable tension, winch control settings, and emergency stop functionality are addressed at different stages of the ride operation but do not pertain to the immediate safety checks conducted on the rolling boarding platform.