The camera could also help direct a helicopter from the ground and be used in civilian roles, like fire fighting or search and rescue.

ECONOMIST: Autonomous helicopters

Backers hope they will prove a cheaper alternative to helicopters and fixed-wing aircraft for tasks as varied as power and pipeline inspection, mapping, security, border surveillance, research, filming, fire fighting, search and rescue and delivering supplies.

ECONOMIST: A small Welsh airport has become an unlikely tech cluster

An aircraft rescue and fire fighting captain reported the battery was hissing loudly and liquid was flowing down the sides of the battery case.

BBC: Boeing 787 Dreamliner: NTSB details battery fire