When helicopters are accomplishing certain special maneuvers such as powered descent, or the like involving low "g" conditions, the helicopter blades may teeter excessively with respect to the mast, and under severe conditions, the mast may shear. To sense such low "g" conditions, which may be dangerous, an accelerometer is mounted on the helicopter frame close to the center of gravity of the helicopter and is coupled to data processing circuitry which classifies the low-g conditions in bands or levels of severity, recording the duration of exceedances in which the low-g conditions are below predetermined levels, and issues warning signals to the helicopter pilot through the helicopter intercom system and a suitable warning light.