Which safety measure is essential for a pilot flying over water in a commercial helicopter?

Automatic flotation devices are essential for a pilot flying over water in a commercial helicopter because they serve a crucial safety function in the event of an emergency ditching. These devices automatically deploy when in contact with water, ensuring that both the aircraft and its occupants remain buoyant. This is particularly important in maintaining the safety of the crew and passengers while they await rescue, as it minimizes the risk of drowning.

In contrast, while emergency beacons are valuable for alerting rescue services, they do not provide direct flotation assistance. Similarly, a map of currents is helpful for navigation but doesn't enhance safety during an in-flight emergency over water. A life raft is also important, but if a helicopter were to ditch, having flotation devices can provide immediate buoyancy support, which is critical as rescue operations may take some time. Therefore, the presence of automatic flotation devices enhances the chances of survival in an emergency scenario over water, making them a vital part of safety equipment.