What condition must the brake be in for a galley service cart during preflight inspection?

For a galley service cart during preflight inspection, it is essential that the brake be in a functional condition. This ensures the safety and stability of the cart while it is being loaded with supplies and also during in-flight service. If the brake is functional, it allows the cart to remain securely in place, preventing any accidents or movement that could occur due to turbulence or cabin shifts.

Having a functional brake is a critical safety measure, as it helps to maintain control of the cart, especially in narrow aisles where space is limited. This reduces the risk of injuries to the crew and passengers and ensures that the cart does not roll unexpectedly. In contrast, if the brake were loose or non-functional, it would pose significant safety hazards, as the cart could move unintentionally, potentially creating unsafe situations during operations.