White out Brown Out

bubble blizzard

Most experienced helicopter crews know full well the severe danger of whiteout and its dirty sibling, the dust-induced ‘brownout’. The danger arises because hovering is a precisely coordinated activity completely reliant upon the accurate assessment of rates and proximities—without visual reference things quickly go bad for the crew. 

Think inadvertent IMC at three to 10 feet above the ground with blade tips spinning at two-thirds the speed of sound only a few more feet above. The helicopter is literally poised on a tornado of air (medium helicopters can easily create a 100 km/h downdraft). When this tornado of air encounters loose dust or snow, it disturbs them, flinging them about madly, and masking visual references required for accurate hovering. 

This article was written for CASA’s flight safety magazine and can be found by clicking here or on the picture. 

© Resonate Safety Solutions 2017