NTSB Identification: MIA07LA131
Nonscheduled 14 CFR Part 135: Air Taxi & Commuter
Accident occurred Thursday, August 09, 2007 in Ridgeville, SC
Probable Cause Approval Date: 12/20/2007
Aircraft: MBB BK-117 A-4, registration: N171MU
Injuries: 5 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The pilot said that upon landing at the scene he kept the helicopter operating with him at the controls, while the medical crew attended to the patient. After loading the patient into the helicopter, the paramedic did a walk around inspection, entered the helicopter, and called out the before-takeoff-checklist, while voicing an alert to the pilot concerning overhanging trees on the port side of the helicopter. The pilot acknowledged, and told the crew that he intended to pick the helicopter up into a hover, slide to the right, and then perform a left pedal turn to exit the scene to the west. The pilot said that while performing a left pedal turn at a hover, a vibration occurred throughout the airframe, and he immediately set the helicopter back on the ground, facing west. An EMS technician on the ground who had been observing the helicopter, stated that after the patient had been loaded into the helicopter, the helicopter was lifted into about a 3-foot hover, and then began to rotate and face into the direction of the light wind, coming from the west. After the helicopter completed the rotation into the wind, the EMS technician stated that it then began to increase altitude, and as the altitude increased the tail rotor struck a small pine tree limb that stuck out about 1 to 2 feet into, and over the westbound traffic lane closest to the median. He said he heard the change in pitch to the sound of the helicopter's engine, and also saw the tail rotor begin a slight "wobbling." At this point the EMS technician said the helicopter was about 6 to 8 feet off the ground, and he believes that the pilot sensed that something was wrong with the helicopter, and set the helicopter down firmly on the curbside lane, facing west. An examination reveal no evidence of a preaccident mechanical failure or malfunction to the helicopter or any of its systems.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The EMS helicopter pilot's failure to ensure adequate obstacle clearance which resulted in the tail rotor impacting a tree during the takeoff.

Full narrative available

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