Helicopter Flight Information
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Helicopter Flight Information |
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Low-G ManeuversLow-G means low gravity. Any maneuver causing a feeling of weightlessness is considered a low-G maneuver. The extent of the condition is variable. Although some people would have you to believe that this condition is only dangerous in a two bladed helicopter, that thought is clearly false. Read this accident report involving a NOTAR. A low-G in itself is dangerous to a lesser degree in a multi-bladed helicopter. In two-bladed helicopters, the maneuver should be avoided like a plague. A low-G condition is in most cases pilot induced by unloading the main rotor usually through a forward cyclic input. Although there are two other conditions that can lead to a low-G (turbulence and abrupt autorotation entry), these are less likely. In both of those conditions the main rotor is unloaded. The most common cause of a low-G condition is an abrupt unloading of the main rotor as a result of an excessive forward cyclic input. This may be to quickly descend for collision avoidance, or an attempt to control the helicopter in turbulent conditions. In a helicopter, the cyclic is never used to control the helicopter in a rapid descent condition, even in turbulence. For collision avoidance (of a bird, or other aircraft for example), a rapid descent in a helicopter must be achieved by lowering the collective while maintaining a level flight attitude with the cyclic, or by cyclic turns. When turbulent conditions are encountered the cyclic must be used to maintain a level flight attitude. The collective must be feathered as needed to control the climbing and descending tendencies caused by wind shear and turbulence. Most importantly however the helicopter must be slowed to a safe operating speed in turbulent conditions.
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