The helicopter can hold only the pilot, operate for 12-15 minutes and has a top speed of 80 knots.

The helicopter can hold only the pilot, no passengers, and operate for 12 to 15 minutes.

An estimated 700 medical helicopters operate nationally, about twice the number flying a decade ago.

And in some areas where helicopters can still operate on private property, neighbors are becoming more vocal about the noise.

In addition, some areas where the helicopters operated had few water sources from which a helicopter could fill its bucket.

The goal was to capture or destroy the main military base there, from where most helicopters in Idlib operated.

Two helicopters operate out of this base and operate 24 hours a day.

Ambulances were used to transport the wounded, as heavy fog meant helicopters could not operate.

The strongest wake can occur when the helicopter is operating at lower speeds (20 to 50 knots).

Critics: Like jets, helicopters operate deep in enemy territory, so pilots risk death or capture.