Incident Overview
A helicopter accident occurred on an elevated helipad following a nighttime air taxi flight. The pilot had completed the flight, deplaned passengers, and was preparing to reposition the aircraft to the operator's base when a door unsecured indication appeared on the instrument panel for the left cabin door.
Sequence of Events
The pilot recalled that passengers had deplaned through the right-hand door and that the left door annunciation had not been present during the inbound flight. Suspecting a passenger may have inadvertently released the left door latch, the pilot reduced engine power to idle and exited the cockpit to check the door. After reclosing the door, the pilot returned to the cockpit, but the door open annunciation activated again. The pilot left the cockpit "2 or 3 times" to address the issue and described feeling "frustrated with it."
During the final exit, the pilot did not recall retarding the engine power control levers to ground idle before leaving the cockpit. While the pilot was outside, the wheel-equipped helicopter began to move on the helipad. The pilot observed the helicopter moving toward the edge of the pad and returned to the cockpit. A confusing sequence of events followed, and the helicopter ended up on its side.
Investigation Findings
Post-accident examination revealed a tire skid pattern on the helipad deck consistent with a dynamic rollover event. The engine power control levers were found in the "fly" position. The pilot reported no mechanical discrepancies with the helicopter prior to the event and noted that the aircraft was very light with no other occupants on board.
Observations
The pilot had completed a nighttime air taxi operation and was operating from an elevated helipad. The recurring door indication and the pilot's multiple exits likely contributed to the situation, but no explicit causal factors are stated in the source.