Three Rivers, MI, USA
N60EA
Bell 206B
The helicopter sustained substantial damage during an emergency landing after liftoff. The pilot reported that a normal takeoff was made to the southwest, and upon reaching an altitude of 75 feet, he began a turn to the south and noticed that the aircraft was not responding to the turn. When the helicopter began to accelerate forward it started to spin to the right and the tail rotor lost all effectiveness. The helicopter spun 3 and 1/2 revolutions and the pilot then maneuvered it to an open pasture for the emergency landing. He lowered the collective bringing the aircraft to the ground for a level touchdown with no forward motion. The pilot stated that a local airport reported a wind from the southeast at 4 knots, and prior to the departure the wind was "non existent." No anomalies were found with the helicopter or its flight control systems that were determined to exist prior to impact. According to the FAA, a loss of tail rotor effectiveness (LTE) is "not related to an equipment or maintenance malfunction and may occur in all single-rotor helicopters at airspeeds less than 30 knots. It is the result of the tail rotor not providing adequate thrust to maintain directional control, and is usually caused by either certain wind azimuths (directions) while hovering, or by an insufficient tail rotor thrust for a given power setting at higher altitudes."
On July 6, 2002, at 0945 eastern standard time (est), a Bell 206B, N60EA, piloted by a commercial pilot sustained substantial damage during an emergency landing after liftoff from a residential driveway in Three Rivers, Michigan. Visual meteorological conditions prevailed at the time of the accident. The personal flight was operating under the provisions of 14 CFR Part 91 without a flight plan. The pilot and passenger reported no injuries. The flight was originating at the time of the accident. According to written statements provided by the pilot, a normal takeoff to the southwest was made and upon reaching an altitude of about 75 feet he began a left turn to the south when he noticed that the aircraft was not responding to the turn. The pilot stated, "I was ... less than 100' from the trees to the South and West and directly over a power line which was about 25' off the ground. Thinking I had lost my tail rotor due to mechanical problems I elected to do a cyclic turn to the North to accelerate and hopefully reach an airspeed to straighten arrest the spin because applications of full left pedal had no response. The aircraft then began to spin faster and efforts to gain forward speed were not possible." The pilot reported that he "identified this as a loss of tail rotor and began to effect an emergency landing. Power lines were below me and the aircraft had already spun 3 and a half complete revolutions. I managed to maneuver the aircraft to an open pasture area and lowered the collective bringing the aircraft down to the ground." The pilot stated that when the aircraft reached the ground the "touchdown was level with no forward motion but was still turning slightly." The pilot reported, "the tails of the skid gear broke off and the aircraft settled down and the tail rotor hit the ground." The pilot stated that a local airport reported a wind from the southeast at 4 knots. The pilot reported that prior to the departure the wind was "non existent." According to the Federal Aviation Administration (FAA) publication, FAA-H-8083-21, "Rotorcraft Flying Handbook", Loss of Tail Rotor Effectiveness (LTE) "is not related to an equipment or maintenance malfunction and may occur in all single-rotor helicopters at airspeeds less than 30 knots. It is the result of the tail rotor not providing adequate thrust to maintain directional control, and is usually caused by either certain wind azimuths (directions) while hovering, or by an insufficient tail rotor thrust for a given power setting at higher altitudes." According to the FAA Advisory Circular, AC 90-95, "the anti-torque control margin established during FAA testing is accurate and has been determined to adequately provide for the approved sideward/rearward flight velocities plus concentration of gusts of reasonable magnitudes. This testing is predicted on the assumption that the pilot is knowledgeable of the critical wind azimuth for the helicopter operated and maintains control of the helicopter by not allowing excessive yaw rated to develop." AC 90-95 describes the conditions under which LTE may occur as "any maneuver which requires the pilot to operate in a high-power, low-airspeed environment with a left crosswind or tailwind creating an environment where unanticipated right yaw may occur. There is greater susceptibility for LTE in right turns. This is especially true during flight at low airspeed since the pilot may not be able to stop rotation. The helicopter will attempt to yaw to the right. The yaw is usually correctable if additional left pedal is applied immediately. If the response is slow, the yaw rate may rapidly increase to a point where recovery is not possible." FAA inspectors performed the postaccident examination of the helicopter. No anomalies were found with the helicopter or its flight control systems that were determined to exist prior to impact.
A loss of tail rotor effectiveness.
Source: NTSB Aviation Accident Database
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