Rotor Blade Clearance
I'm fixed wing type so forgive what might be a naieve question; but I was watching a video of a SAR Helio involved in a 'daring do' cliff rescue and wondered how on earth the crew can judge the proximity of the blades to rock. Of course, its no doubt something that comes with training and experience, but I wondered if there is an electronic device that gives the pilot an indication as to blade proximity- sort of like the things you have in cars for reversing- go beep when close and, beep beep beep when you're really too close. Or perhaps it when the winchman screams!