Incident Details
On takeoff from an automobile accident site, with a patient on board, the air ambulance flight made a climbing right turn and flew into power lines. Witness marks on the helicopter indicated it struck the transmission line from below and impacted the ground in an inverted attitude below and to the west of the lines.
Lighting and Visibility
Light conditions were a dark night with emergency response, construction, and emergency response vehicle lights illuminating the landing site area. The light conditions prevented the pilot from seeing anything outside the lighted area.
Power Line Description
The existence of the power lines was unknown to the fire rescue on-scene commander. The unmarked power lines were 622 feet apart and oriented northeast/southwest. The southern tower was 106 feet high and the northern tower 83.5 feet high. The towers and lines did not meet obstruction-marking criteria and were not marked. In addition, they were not depicted on sectional or topographic maps.
Departure Procedures
Company policy, promulgated through documents and training, provided landing zone departure procedures which instructed the pilot to climb straight ahead in a near vertical climb to a minimum of 300 feet agl before turning. The horizontal distance from the helicopter's takeoff position to the power line was approximately 630 feet based on global positioning system (GPS) measurement.