A method developed in Switzerland with vortex phenomena on the helicopter should protect pilots with a life-saving technique from the fatal crash. The acceptance differs in various aviation authorities, international safety teams as well as helicopter manufacturers and is discussed as violently. From the perspective of a pilot, however, all techniques should be known in order to be able to free themselves from their respective life-threatening situations.
The basic prerequisite for a vortex ring in which the helicopter rushes with increasing vertical velocity towards the ground are:
- Main rotor must be powered by the engine (no autorotation)
- no or low forward airspeed
- high vertical rate of descent depending on the helicopter type
The Vuichard method presents a guide line to the pilot in a vortex situation with a tilting movement immediately to the left or right out of the vertical descent. For this purpose, the collective lever is to be increased up to the maximum allowable power, while at the same time the power pedal of the tail rotor control for directional stability as well as the cyclic (control stick) are moved in the opposite direction of the power pedal. This cross movement – power pedal left stepped – cyclic to the right or vice versa, depending on the direction of rotation of the main rotor – should lead the helicopter out of the own downwash. According to Vuichard, the Swiss inventor of this method, the rotor tips reach the upwind side of the vortex and terminate the height loss within a few meters (6-15 meters).
As explained in the ProPilots training app using 3D movies, the Vortex ring state can be left in all directions. In recent decades, pilots have been instructed to reduce the collective lever in a vortex state and move the cyclic forward. Close to the ground or in the case of surrounding obstacle, this action is no longer practicable. In addition, the (un-) experienced pilot is too late to recognize the danger of the vortex ring. As a consequence he has no chance to react in time and correctly unfortunately.
Ultimately, it is up to each pilot himself to apply his countermeasures in the individual situations. Regardless of which procedure the pilot decides whether
- the generally applicable procedure – collective downward – cyclic forward,
- the Vuichard method,
- or an autorotation landing close to the ground, all have the same goal to prevent the hard landing or the crash.
However, the most important aspect for the pilot, which has been impressively visualized with the ProPilots app, is to avoid the vortex ring state in general. To recognize this danger in case of vertical approaches in time, to interpret first signs correctly, offer the best alternative for the pilot.