That's why they're called 'choppers'
GULFSTREAM IV AND BELL 206, SAN DIEGO, CALIF., MAY 12, 2001–Thirteen people–pilots, passengers and line-service personnel–escaped injury when the rotor blades of an engine-starting helicopter smacked into the winglets of a taxiing GIV. The incident happened on a ramp at the San Diego International-Lindbergh Airport (SAN) around 5 p.m.
Since the ramp area had been busy all day, four wing walkers were supervising the transition of the two aircraft. A wing walker stood at each wing of the business jet, one stood by the nose and one helped passengers getting aboard the helicopter. As the Gulfstream began to move past the helicopter, all thumbs were up. The helicopter pilot finished boarding his passengers, closed the door and slid into the cockpit.
Just as the GIV’s nose was passing the helicopter, the helo pilot started the Bell 206’s engine and the blades began to turn. One wing walker heard the whine of the starting engine, turned toward the helicopter and tried to get the pilot’s attention, but it was too late. Pieces began to fly as the helicopter blades caught the GIV’s winglet. The wing walkers ducked to avoid the debris. One wing walker told the NTSB he had no warning and did not see the helicopter pilot clear the area before startup.
The Gulfstream and Bell pilots were operating under Part 91 and the NTSB interviewed both of them. The Bell pilot said he “started the engine and saw N999GP [the GIV] coming down the taxiway.” He told the NTSB he did not think the two aircraft would collide and ignored his passenger’s comments to the contrary. He had not yet contacted ground control as he was just starting the engine at the time of the incident.
The GIV captain and first officer reported that the cockpit was past the helicopter blades, which weren’t yet turning at the time. The first officer saw the line-service tech give him a thumbs-up as they passed the helicopter and then heard the thump of the winglet hitting the blades. The captain said he didn’t hear the impact.