NTSB Identification: DFW05FA073
Nonscheduled 14 CFR Part 135: Air Taxi & Commuter
Accident occurred Monday, February 21, 2005 in Gentry, AR
Probable Cause Approval Date: 10/03/2006
Aircraft: Bell 206-L1, registration: N5734M
Injuries: 1 Fatal,3 Serious.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The purpose of the air medical flight was to pick up a patient who had been involved in a motor vehicle accident in a rural area, and to transport him to a hospital. The helicopter landed to the north on the front lawn of a private residence. After the patient was boarded, the commercial pilot attempted to determine the wind direction, but found no visual cues. However, he estimated the winds were about 10-15 knots from between 330 and 030 degrees. He stated that he had encountered similar winds while en route to the landing zone. A second EMS pilot who arrived at the scene after the accident stated that the winds were from 030 to 050 at 10 knots. The accident pilot stated that he brought the helicopter to a hover and maneuvered the helicopter to the right to avoid power lines that crossed the residential property. The pilot stated that when he departed, he began a vertical ascent but was trying not to increase the collective above the available torque. He stated that he was concerned about clearing the power lines and losing tail rotor effectiveness. When the helicopter reached an altitude abeam of the power lines, it began an uninitiated spin to the right. The pilot stated that the torque was near 100 percent. He applied full left torque pedal, and attempted to gain forward airspeed. He also used the cyclic to follow the nose of the aircraft in an attempt to fly out of the turn. The pilot was unable to gain airspeed and the helicopter continued to spin to the right and to descend. The pilot initiated an autorotation by lowering the collective and placing the throttle in the idle position, which he stated stopped the spinning. When the helicopter was about 10 to 20 feet above ground, the pilot placed the collective in the full-up position to cushion the landing. However, there was not sufficient main rotor rpm to stop the high rate of descent and the helicopter landed hard in a field adjacent to the private residence. Examination of the helicopter revealed no preimpact structural, system, or other mechanical anomalies. A critical wind azimuth in the Bell 206-L1 flight manual indicated an increased risk of loss of tail rotor effectiveness when winds are encountered between 050 and 210 degrees.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot’s improper decision to maneuver in an environment conducive to a loss of tail rotor effectiveness. Full narrative available
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