Helicopter bucket

A helicopter passing over a bush fire, with a bucket slung below it. Water is being dropped on the fire from the bucket.
A Bell 206 using a bucket during a training flight in Maranhão, Brazil

A helicopter bucket or helibucket is a specialized bucket suspended on a cable carried by a helicopter to deliver water for aerial firefighting. The design of the buckets allows the helicopter to hover over a water source—such as a lake, river, pond, or tank—and lower the bucket into the water to refill it. This allows the helicopter crew to operate the bucket in remote locations without the need to return to a permanent operating base, reducing the time between successive drops.

Each bucket has a release valve on the bottom which is controlled by the helicopter crew. When the helicopter is in position, the crew releases the water to extinguish or suppress the fire below. Each release of the water is referred to as a drop.