Casualties unknown

2007-08-09: Mbb BK-117 A-4 (N171MU) — Omniflight Helicopters Inc., — Ridgeville, SC

Ridgeville, SC, US

On August 9, 2007, a Mbb BK-117 A-4 (registration N171MU) operated by Omniflight Helicopters Inc., was involved in an aviation accident near Ridgeville, SC. Investigators recorded the probable cause as: The EMS helicopter pilot's failure to ensure adequate obstacle clearance which resulted in the tail rotor impacting a tree during the takeoff. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

A helicopter struck a tree limb with its tail rotor while attempting a left pedal turn during a hover at a landing scene. The pilot set the aircraft down after noticing a vibration. No mechanical failure was found.

Incident Description

A helicopter landed at a scene to pick up a patient. The pilot kept the helicopter operating while medical crew attended to the patient. After loading, a paramedic performed a walk-around inspection, entered the helicopter, and called out the before-takeoff checklist. The paramedic alerted the pilot about overhanging trees on the port side. The pilot acknowledged and stated his intention to lift into a hover, slide to the right, and perform a left pedal turn to exit westward.

While performing the left pedal turn at a hover, a vibration occurred throughout the airframe. The pilot immediately set the helicopter back on the ground, facing west.

An EMS technician who observed from the ground reported that after the patient was loaded, the helicopter lifted into a hover of about 3 feet, then rotated to face the wind from the west. After completing the rotation, the helicopter began to increase altitude. As altitude increased, the tail rotor struck a small pine tree limb that protruded 1 to 2 feet into and over the westbound traffic lane closest to the median. The technician heard a change in engine pitch and observed the tail rotor begin to "wobble." At that point, the helicopter was about 6 to 8 feet off the ground. The technician believed the pilot sensed something wrong and set the helicopter down firmly on the curbside lane, facing west.

Examination Results

An examination revealed no evidence of a preaccident mechanical failure or malfunction of the helicopter or any of its systems.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20070827X01242. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.