CHI02FA174

A loss of tail rotor effectiveness and the pilot's failure to maintain control of the helicopter. Factors associated with the accident were the binding of the tail rotor pitch changed rod, the gusty wind conditions, and the pilot’s lack of total experience in this make and model of helicopter.

The helicopter impacted the terrain following a loss of control. Shortly after departing the hospital on a medivac flight, the pilot requested that company dispatch have the company mechanic meet him at a nearby airport because he was experiencing "binding in the right pedal." An airport employee stated that just prior to the accident, she saw the helicopter hovering over the ramp and thought it was going to land. Four other witnesses reported seeing the helicopter climbing and thought it was taking off. Witnesses also reported seeing the helicopter spinning (directions vary) prior to it descending to impact. One witness reported the nose of the helicopter was stationary on an east heading and the tail of the helicopter was swinging back and forth. He stated the helicopter then veered to the left and he lost sight of it when he traveled behind some buildings. Another witness reported seeing the helicopter rocking nose to tail and going in a circle, but not spinning, prior to impact. Inspection of the helicopter revealed one of the scuff sleeves on the tail rotor pitch change rod was moved approximately 3 inches aft of the bearing bracket. The top of the sleeve was gouged and scuffed. Both the forward and aft ends of the sleeve were slightly curled away from the rod. The forward edge of the sleeve was torn. No other mechanical failure or malfunction of the engine, airframe, or systems were identified that would have resulted in the accident. The guarded hydraulic cut off switch was found in the off position. Records show the pilot had approximately 2,500 hours of helicopter time with a total of 43.8 hours of flight time in this make and model of helicopter. Winds at the time of the accident were from 200 degrees at 16 knots, gusting to 21 knots. The Federal Aviation Administration Rotorcraft Flying Handbook states that a loss of tail rotor effectiveness "may occur in all single-rotor helicopters at airspeeds less then 30 knots. It is the result of the tail rotor not proving adequate thrust to maintain directional control, and is usually caused be either certain wind azimuths (directions) while hovering, or by an insufficient tail rotor thrust for a given power setting at high altitudes."

HISTORY OF FLIGHT On June 21, 2002, at 1207 central daylight time, a Eurocopter AS-350-B2, N852HW, operated by Rocky Mountain Holdings LLC (RMH), as LifeNet flight 12, experienced a loss of control and collision with the terrain at the Karl Stefan Memorial Airport (OFK), Norfolk, Nebraska. The commercial rated pilot, paramedic, and flight nurse were all fatally injured. The Title 14 CFR Part 91 flight was operating in visual meteorological conditions on a company flight plan. The flight originated from the helipad at the Faith Regional West Hospital (NE68), in Norfolk, Nebraska, at 1200. N852HW was based at the Faith Regional Health Services West Campus Heliport (NE68) in Norfolk, Nebraska. NE68 is located approximately 2.5 miles north-northwest from OFK. The purpose of the flight was to fly to St. Anthony's Hospital in O'Neill, Nebraska, to pick up a patient. The patient was then going to be transported to the Mercy Medical Center in Sioux City, Iowa. At 1152:46, the pilot was informed of the mission by LifeCom dispatch. At 1201:20, the pilot radioed the LifeCom dispatcher and reported that he had departed. At 1203:25, the pilot reported to dispatch that he was going to land at OFK, and he asked the dispatcher to contact their mechanic and have him meet the aircraft. He reported "we're gonna have to land and get something checked out with maintenance before we can take this mission." The dispatcher began the process of locating the mechanic. At 1205:10, the pilot informed the dispatcher that they were experiencing "binding in the right pedal." This was the last transmission between the helicopter and dispatch. Several witnesses reported seeing the helicopter just prior to the accident. The person monitoring the Unicom radio at the Karl Stefan Airport reported that the pilot of N852HW made a radio call saying he was inbound for landing. She stated she responded to the call and asked if they were going to need fuel. There was no response to her inquiry. She stated she then saw the helicopter hovering over the ramp, about 10 feet off the ground, and thought he was gong to land. She stated she answered the telephone and seconds later when she looked back out the window she noticed the helicopter had crashed. The pilot of an airplane that was landing at OFK reported that he was entering the traffic pattern for runway 19 when he heard the helicopter report being north of the city, landing to the south. He stated that he asked the helicopter three times for a position report, but he did not get a response. He stated that when he was on a one mile final, he saw the helicopter "high right [the witnesses right], descending across to low left [the witnesses left] view (at a high rate of descent)." The helicopter passed between his aircraft and the runway threshold. He stated he aborted his landing to avoid the helicopter. When he was turning crosswind, he saw the helicopter descend toward the north end of the ramp and he thought it was landing. He turned his attention to flying his airplane and when he looked back toward the helicopter he saw it "crashing on its side and coming to rest." A witness who was traveling south on Highway 81 reported seeing the helicopter hovering over the northern quadrant of the airport. He lost sight of the helicopter, and then saw it climb to a height of about 100 to 200 feet where it leveled off and hovered. He reported, "it suddenly began to spin (I believe counter-clockwise, but upon reflection, I'm not positive) with its nose angled down, and a moment later it started to descend rapidly, still spinning, apparently out of control. After several complete revolutions, the helicopter dove to the ground, coming to rest on its right side." This witness went to the helicopter to help. He reported hearing an "occasional release of pressure from what I believed to be the hydraulic systems, and from time to time there would be a brief puff of smoke from the exhaust." Another witness who was located approximately a quarter-mile northwest of the accident site reported that the helicopter stopped for a short time and hovered over his location. He reported that as the helicopter proceeded to the airport "it pitched side ways and the pilot hit the power and got the helicopter back up in the air." He reported the helicopter then began to spin clockwise (looking down from the top). He stated the spin slowed as the helicopter gained altitude then it "dove forward and down into the ground." Another witness who was at the intersection of Highway 81 and Sherwood Road reported seeing the helicopter about 70 feet southwest of the 2 north buildings at the airport at an altitude of about 30 feet above the ground with its nose pointed to the east. The nose of the helicopter was at an angle, which was about 30 degrees lower than the tail. The witness stated the tail swung about 3 times from the northwest to the southwest and the nose of the helicopter remained in the same position. The helicopter then veered to the left. Buildings blocked his view and the next thing he saw was a cloud of dust. Another witness reported seeing the helicopter prior to it reaching the airport. She stated that it was "rocking (nose to tail) and going in a circle, it was not spinning when I saw it." A witness driving south on Highway 81 reported seeing the helicopter climbing out from the airport and thought it was taking off. She stated it reached an altitude about twice the height of the buildings (hangars) at which time it started to spiral. She stated the helicopter then turned and dove nose first into the ground. A witness traveling north on Highway 81 reported he thought the helicopter was taking off prior to the accident. He reported the helicopter then started to fly "strangely" prior to it impacting the ground. Another witness reported seeing the helicopter in a level attitude and traveling very slow as it approached the airport. She stated the helicopter banked a little when it got close to the hangars. It started spinning counterclockwise then it began to spin in a clockwise direction. She stated the helicopter descended and climbed back up at which time she was distracted. She then saw the helicopter dive into the ground. She stated the helicopter was about twice the height of the buildings when it started spinning. PERSONNEL INFORMATION The pilot, age 43, received a commercial pilot certificate with rotorcraft-helicopter and instrument-helicopter ratings on November 8, 1985. This certificate was issued based on the pilot's previous military experience. On December 31, 1989, an airplane-single engine land rating was added. On January 26, 2002, a multi-engine land rating was added. On the application for this certificate, the pilot reported having 161.1 hours of airplane flight time and 2,418.5 hours of rotorcraft flight time. On February 5, 2002, a multi-engine instrument rating was added to the pilot's commercial pilot certificate. On the application for this certificate, the pilot reported having 180.6 hours of airplane flight time and 2,399.7 hours of rotorcraft flight time. The pilot's last Federal Aviation Administration medical certificate was issued on November 15, 2001. On that date, the pilot was issued a second-class medical certificate with no limitations. The pilot was a member of the Nebraska Army National Guard in Lincoln, Nebraska. According to information supplied by his National Guard Unit, the pilot had approximately 2,550 hours of total flight time. They reported he had about 680 hours of flight time in UH-60 Blackhawk helicopters. The National Guard reported that between November 1, 2001, and May 1, 2002, there was a void in the pilot's flight hours. He had fixed wing aircraft training in May 2002, and he had flown 3 hours in June 2002. The pilot submitted an Application for Employment to RMH, dated November 21, 2001