Winching some stuff from a Huey down to an Army location in the north QLD rainforest in the mid-80s - small hole in the trees marked by smoke - all's proceeding well, with us in contact with the guys on the ground on VHF-FM.
The radio chat from the ground is all relaxed and low key until suddenly his voice goes up an octave - after a while it turns out we'd blown a dead limb off a tree and hit one of the blokes on the ground; not serious injuries, luckily, but enough so they needed a medevac. Luckily there was a helicopter on-scene - us!