Every firefighting helicopter has to answer the same question dozens of times a day: how do I get the next load of water aboard as fast as possible? There are two main answers.
The bucket
A firefighting bucket is a large, collapsible, open-topped container that hangs from the helicopter’s cargo hook on a cable, the long line. One brand, the Bambi Bucket, is so common that its name is often used for all of them.
Filling: the pilot slows to a hover over the water and lowers the bucket in. It tips, sinks and fills in seconds. Some buckets have pumps, so the pilot can power fill with only the bottom of the bucket in shallow water.
Dropping: a valve in the bottom opens and the water falls straight out, as a tight column.
Why use one:
- It works from water too small or tree-lined for the helicopter to hover low over, because the helicopter stays high above on a 100–150 ft line.
- Nearly any helicopter with a cargo hook can carry one, from light to heavy.
- It’s simple, and it can be swapped onto another aircraft quickly.
The catch: the bucket swings. Accelerating, turning or stopping sets it swinging like a pendulum, and the pilot has to let it settle before an accurate drop. Long lines also take skill near trees and terrain.
The tank and snorkel
Other helicopters carry water in a tank, either strapped to the belly (like a “Firehawk” Black Hawk) or built in (like the Skycrane’s). They fill through a hover snorkel: a hose with a pump at its tip that hangs below the aircraft.
Filling: the pilot hovers low over the water so the snorkel’s tip is submerged, and the pump pushes water up into the tank, typically filling it in under a minute. Snorkels can draw from water as shallow as about 18 inches.
Dropping: doors under the tank open. A computer-controlled door system can release the whole load at once or in parts, and lay a longer, thinner line at speed.
Why use one: no swinging load, so the helicopter can fly faster to and from the fire, and drops are easier to control. Tanks often also carry foam concentrate.
The catch: the helicopter has to hover very low over the water to fill, so the source needs room and a clear approach.
The sea snorkel
Some tank helicopters, like the Skycrane, can also lower a ram scoop, sometimes called a sea snorkel, and fill while moving, skimming a few feet above the water at around 30–40 knots. That saves the time it takes to slow to a hover.
In Dip & Drop
You get all three:
- The Chinook and Black Hawk come with either a tank or a bucket, and the Huey flies a bucket.
- The Skycrane can hover-fill or scoop on the move.
- Buckets swing on the line and can be dunked for a fast fill or power-filled from shallow water. Snorkels lower by themselves when you come in low and slow over water.
Fill times are shortened to keep the game moving, but the technique is the same: slow, low, steady.