Today a Bell helicopter crashed into Pearl Harbor near the Arizona Memorial. Reports are that everyone survived.
Some are saying the helicopter experienced engine failure. Unlikely. Instead, the pilot probably experienced "settling with power." That’s when the helicopter is forced down by the downdraft it creates with its own rotors. To avoid crashing, the pilot must ease up on the power. In the video, you can hear power increasing. Adding power (or torque) just makes things worse.
From the FAA’s Rotorcraft Flying Handbook:
When recovering from a settling with power condition, the tendency on the part of the pilot is to first try to stop the descent by increasing collective pitch. However, this only results in increasing the stalled area of the rotor, thus increasing the rate of descent. Since inboard portions of the blades are stalled, cyclic control is limited. Recovery is accomplished by increasing forward speed, and/or partially lowering collective pitch. In a fully developed vortex ring state, the only recovery may be to enter autorotation to break the vortex ring state. When cyclic authority is regained, you can then increase forward airspeed.