Violent convulsions Supporting EvidenceĪ study conducted by the U.S.

In extreme cases the follwing effects may also be experienced:Ĩ.

However, the common symptoms are (Kern, 2002 ) and (Reinhart, 2008 ): The signs and symptoms of Flicker Vertigo can be various. The CFF which varys from individual are ranged from 25hertz to 55 hertz. This 'Critical Flicker Frequency' (CFF) will occur only with mutiple factors related to lighting sources, the indivdual viewing the lights and the enviroment/situation. If the modualtion is adequate, the visual system will percieve the flicking continuous lights as STEADY, in which Flicker Vertigo will not occur. The activities of the retina and the brain are synchronized in order to create this visual process. With the eyes and brain processing acting together it precieves the amount of flicking light. The phenomenon of Flicker Vertigo can be derived from the study of eyes and brains interaction. The Perception of Flicker and the Interaction of Eyes and Brains Flicker vertigo can develop when viewing rotating beacons, strobe lights, or reflections of these off water surfaces or the clouds. During night flying, anti-collision lights reflecting off the clouds can produce the same effect. ĭuring daylight, flicker vertigo can be caused by the sunlight flickering through the rotor blades or propeller. The strobe light effect causes persons who are vulnerable to flicker vertigo to become disoriented, lose control of the aircraft or have a seizure.

Flicker vertigo in the helicopter occurs when the pilot or front passenger looks up through the blades of the main rotor as it turns in the sun causing the light to strobe. Theoretical frameįlicker vertigo is a phenomenon that is more prone to happen during helicopter flights, but it can occur in fixed wing flight (turbo propellers) whenever flickering light conditions exist.

Flicker Vertigo as defined by The Flight Safety Foundation (FSF) describes flicker vertigo as “an imbalance in brain cell activity caused by exposure to low-frequency flickering (flashing) of a relative bright light”.Īnother definition of Flicker Vertigo by U.S Air Force Flight Surgeon's Guide stated that Flicker Vertigo can be a result of exposure to sun or light passing through a rotor blade system, producing a modorate frequency flicker into the cabin, similiar to the flicker of a failing neon light tube.