Aviation Accident Summaries

Aviation Accident Summary FTW00LA206

ALLEN, TX, USA

Aircraft #1

N312LS

Mbb BK-117-A3

Analysis

The commercial helicopter pilot terminated the night approach to a 6 to 8-foot hover, with 'trees and 2 post-box's to the right and a large ditch to the left.' The pilot hovered the helicopter sideways to the left to move away from the trees. He then started a left pedal turn to face EMS units located behind the helicopter. He had turned the helicopter approximately 120 degrees, 'when I moved backwards' and struck the trees with the tail rotor. He immediately stopped the turn and moved the helicopter forward before losing tail rotor control. As the helicopter began to spin, he 'lowered the collective and landed hard.' The tail rotor drive shaft forward of the 45 degree gearbox was sheared.

Factual Information

On July 16, 2000, at 0140 central daylight time, a MBB BK-117-A3 helicopter, N312LS, was substantially damaged when the tail rotor contacted trees while hovering in-ground effect near Allen, Texas. The helicopter was registered to the General Electric Capital Corporation of Dallas, Texas, and operated by Omniflight Helicopters, Inc., of Addison, Texas. The commercial pilot and the two medical crewmembers were not injured. Dark night visual meteorological conditions prevailed, and a company VFR flight plan was filed for the 14 Code of Federal Regulations Part 91 positioning flight. The air ambulance flight originated from the Garland/DFW Heloplex Heliport, Garland, Texas, at 0130. The pilot reported that he terminated the night approach to a 6 to 8-foot hover, with "trees and 2 post-box's to the right and a large ditch to the left." He hovered the helicopter sideways to the left to move away from the trees. He then started a left pedal turn to face EMS units located behind the helicopter. He had turned the helicopter approximately 120 degrees, "when I moved backwards" and struck the trees with the tail rotor. He immediately stopped the turn and moved the helicopter forward before losing tail rotor control. As the helicopter began to spin, he "lowered the collective and landed hard." The FAA inspector, who examined the helicopter, reported that the tail rotor drive shaft forward of the 45 degree gearbox was sheared. Both tail rotor blades sustained damage, and the aft cross tube for the landing skids was spread.

Probable Cause and Findings

the pilot's failure to maintain obstacle clearance while hovering the helicopter. A contributing factor was the dark night light conditions.

 

Source: NTSB Aviation Accident Database

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