Aviation Accident Summaries

Aviation Accident Summary DFW07LA171

Marks, MS, USA

Aircraft #1

N90AE

Bell 206L-1

Analysis

The commercial pilot reported that he noted that the wind sock atop the hospital was limp prior to starting the engine. He added that the helicopter was parked on a westerly heading when the patient was loaded aboard the helicopter. The pilot added that he brought the helicopter to a hover, prior to executing a right hovering turn to the right for his planned departure in a northerly heading. The pilot further stated that he initiated a vertical takeoff on a northerly heading to clear the obstacles. The pilot added that "after reaching an altitude that allowed the rotor system to be slightly above the trees, the aircraft began a slow turn to the right." The pilot countered with left anti-torque pedal and the torque increased to 101 percent and he "backed-out on the amount of left pedal input." The pilot then attempted to "nurse the aircraft" at the 100 percent torque indication to avoid an engine over-torque condition. The pilot then lowered the collective as he attempted to remain over the helipad and land. The pilot added that the rate of turn to the right decreased some, but was not totally arrested. The helicopter landed hard while on a left yaw on a grassy area approximately 20-feet short of the helipad. The landing gear collapsed and the helicopter came to rest on its left side. The investigation revealed that the helicopter was within weight and balance limits at the time of the mishap. The helicopter was recovered to a secured location for further investigation. The 3,884-hour helicopter pilot reported having accumulated 83 hours in the last 90-days and 21.3 hours within the last 30-days. The pilot reported that he was familiar with the mission and had operated from the same heliport on previous occasions. Flight and engine control continuity was established. No mechanical discrepancies were found with the helicopter or the powerplant.

Factual Information

On July 28, 2007, at 0157 central daylight time, a single-engine Bell 206L-1 helicopter, N90AE, was destroyed upon impact with the ground following a loss of control while attempting to takeoff from a helipad at the Quitman County Hospital near Marks, Mississippi. There were 4 persons aboard the helicopter at the time of the mishap. The commercial pilot sustained minor injuries, one paramedic was seriously injured, while the patient and the flight nurse were uninjured. The helicopter was owned and operated by Air Evac EMS, Inc., of West Plains, Missouri. Dark night visual meteorological conditions prevailed throughout the area for the 14 Code of Federal Regulations Part 135 air medical transport flight. The flight, which was destined to the Med Hospital in Memphis, Tennessee, was originating at the time of the mishap. An FAA inspector, who traveled to the accident site, reported that flight was originating from a confined hospital helipad that is bordered by 40 to 50-foot trees and marked transmission wires. The commercial pilot reported that the noted that the wind sock atop the hospital was limp prior to starting the engine. He added that the helicopter was parked on a westerly heading when the patient was loaded aboard the helicopter. The pilot added that he brought the helicopter to a hover, prior to executing a right hovering turn to the right for his planned departure in a northerly heading. The pilot further stated that the initiated a vertical takeoff on a northerly heading to clear the obstacles. The pilot added that "after reaching an altitude that allowed the rotor system to be slightly above the trees, the aircraft began a slow turn to the right." The pilot countered with left anti-torque pedal and the torque increased to 101 percent and he "backed-out on the amount of left pedal input." The pilot then attempted to "nurse the aircraft" at the 100 percent torque indication to avoid an engine over-torque condition. The pilot then lowered the collective as he attempted to remain over the helipad and land. The pilot added that the rate of turn to the right decreased some, but was not totally arrested. The helicopter landed hard while on a left yaw on a grassy area approximately 20-feet short of the helipad. The landing gear collapsed and the helicopter came to rest on its left side. On site examination revealed that the landing gear was collapsed. The underside of the helicopter sustained severe crushing damaged and was leaning to the left consistent with the reported ground impact in a right yaw. The tailboom was severed by the main rotor blades and there was evidence that the main rotor blade had impacted the ground. The tail rotor blades were also found to have contacted the ground. The main transmission was found partially separated from the airframe. The helicopter was reported to have 55-gallons of fuel on board at the time of the mishap. An unknown quantity of fuel leaked from the wreckage; however, there was no post-impact fire. The investigation revealed that the helicopter was within weight and balance limits at the time of the mishap. The helicopter was recovered to a secured location for further investigation. The helicopter was powered by 650-horsepower Allison model 250-C30P engine, serial number CAE-900040. The engine was removed from the airframe and test ran. No discrepancies were found with the powerplant. Flight and engine control continuity was established. The 3,884-hours helicopter pilot reported having accumulated 83 hours in the last 90-days and 21.3 hours within the last 30-days. The pilot reported that he was familiar with the mission and had operated from the same heliport on previous occasions. The pilot did not report any engine anomalies prior to the loss of control. The flight nurse seated in the right rear seat was able to egress unassisted and she was able to provide assistance to the pilot in the right front seat. The paramedic, who was seated in the left rear seat was unable to egress the helicopter until the aircraft structure was removed from around him. The paramedic remained conscious and sustained serious injuries. The patient that was being transported was not further injured and was assisted by the first responders. At 0200, the weather reported at Kunica, Mississippi (KUTA), approximately 27 miles to the north of the accident site, was reporting winds from 190 degrees at 04 knots, visibility of 10 statute miles, clear skies, temperature 23 degrees Celsius, dew point 21 degrees Celsius, and an altimeter reading of 29.91 inches of Mercury.

Probable Cause and Findings

The loss of control and hard landing as result of the loss of tail rotor effectiveness. A contributing factor was the prevailing dark night conditions.

 

Source: NTSB Aviation Accident Database

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