DFW05FA073

The pilot’s improper decision to maneuver in an environment conducive to a loss of tail rotor effectiveness.

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.

HISTORY OF FLIGHT On February 21, 2005, at 1339 central standard time, a single-engine Bell 206-L1 helicopter, N5734M, operated by Air Evac Lifeteam was substantially damaged during a hard landing following a loss of control while hovering out of ground effect near Gentry, Arkansas. The commercial pilot, the flight nurse, and the paramedic were seriously injured and the patient was fatally injured. The helicopter was registered to Air Evac Leasing Corporation, of West Plains, Missouri, d/b/a Air Evac Lifeteam, and was destined for Springdale, Arkansas. No flight plan was filed and visual meteorological conditions prevailed for the air medical transport flight conducted under 14 Code of Federal Regulations Part 135. According to Arkansas State Police reports, the patient was involved in a single motor vehicle, rollover traffic accident. A dispatcher with Bentonville Fire and Ambulance, Bentonville, Arkansas, dispatched ground units to the accident scene and contacted Air Evac Lifeteam. She told the Air Evac Lifeteam dispatcher that she had no details of the patient's injuries but the situation was "bad." The dispatcher requested helicopter support and provided global positioning system (GPS) coordinates of the accident site. A review of Air Evac Lifeteam's radio transmissions revealed that at 1231, the Claremore, Oklahoma, based crew was dispatched to the accident site because the Springdale, Arkansas, crew were responding to another call. At 1239, the helicopter departed Claremore Regional Airport, and one minute later a crewmember reported there were three people on board and their estimated time en route was 20-30 minutes. While en route, the pilot contacted dispatch and informed them that they were unable to locate the motor vehicle accident and requested an update of the accident site's GPS coordinates. The dispatcher contacted Bentonville Fire and Ambulance and learned that there were no changes to the GPS coordinates. The pilot and crew continued to search for the vehicle accident site. Meanwhile, the patient had been transported via ambulance approximately one-half mile south of where the vehicle accident occurred to a designated landing zone, which was the front lawn of a private residence. About 1327, a helicopter crewmember contacted dispatch and reported that they had located the site and were landing at the designated landing zone. An Arkansas State Trooper, who had escorted the ambulance, reported that he observed the helicopter circle over the accident site, and then execute an approach to the north and land. The patient was then transferred over to the flight crew and loaded on to the helicopter. The Trooper observed the helicopter as it departed. He said he heard the helicopter's engine achieve full power and then it began a vertical climb to approximately 100 feet, when it began to spin. The helicopter continued to spin, before it got "silent' and dropped to the ground in a field adjacent to the landing zone. Several emergency medical service (EMS) personnel also observed the helicopter as it departed. Each reported similar accounts of how the helicopter started to spin shortly after it departed, and subsequently land in the field. A witness, who owned the property where the helicopter had landed, was in her backyard when she observed the helicopter depart. She said the helicopter was initially parked in her front yard facing the north. As it departed, the helicopter ascended and then began to slowly spin to the right as it maneuvered over her house and toward an open field adjacent to her home. She said the helicopter began to spin faster, and after it made several rotations it "dropped" and landed upright in the field. The witness could not recall how high the helicopter was above the ground when it started to spin, but she felt that it was too low. She also stated that she did not hear any unusual noises from the helicopter during its short flight. The pilot was interviewed in the hospital the day after the accident. He stated that during his recon of the landing zone, he could not find any indicators that would assist him with determining wind direction; however, when he had reviewed the weather that morning the winds were reported out of the north between 330 and 030 degrees and were "brisk", about 10-15 knots. The pilot was also able to identify and verify all obstacles reported by his crew in the vicinity of the designated landing zone. After the patient boarded, the pilot stated that he lifted the helicopter to a hover and then pointed the nose of the helicopter on a heading of 360 degrees. While still in a hover, the pilot maneuvered the helicopter to the right and stopped when he was about 25 feet from the property owner’s home. He did this to avoid about 60-foot power lines that ran diagonally in front of the helicopter from southwest to northeast. Another set of power lines that ran north to south were located behind the home. Both sets of power lines converged at the same wooden utility pole, which was located north of the home. 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 added that he was concerned about clearing the power lines and losing effectiveness of the tail rotor. When the helicopter reached an altitude nearly abeam of the power lines, it began an uncommanded spin to the right. The pilot noted that the torque was nearly 100 percent. The pilot had full left torque pedal applied at the time, and said that he attempted to gain forward airspeed, and 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 began to spin to the right and descend. The pilot stated that his only option was to initiate an autorotation, so he lowered the collective and placed the throttle in the idle position, which he stated stopped the spinning. When the helicopter was approximately 10-20 feet above the ground, the pilot placed the collective to the full-up position to cushion the landing; however, there was not sufficient main rotor rpm to stop the high rate of descent. After the impact, the pilot said the engine was still running so he secured the helicopter, which included turning off the fuel valve and battery switch. The helicopter was equipped with an In-Flight Position System (IPS), which tracked the helicopter's movement as soon as its skids broke ground. A review of IPS data revealed that the helicopter departed Claremore Regional Airport at 1239, and landed at the designated landing zone near the accident site at 1327, a 48-minute flight. It then departed at 1335 with the patient onboard, and landed in a field four minutes later at 1339, the time of the accident. In addition, a review of the helicopter's complete flight from Claremore to the accident site revealed that the helicopter did not proceed directly to the accident site, which was approximately 50 miles east of Claremore, Oklahoma. Instead, it flew on a northeasterly, then easterly course, toward the Gravette Medical Center Hospital, Gravette, Arkansas. After the helicopter passed the hospital, it made a right 180-degree turn and proceeded to fly westbound for several miles before it made a left turn and headed south toward the accident site. According to the pilot, he set the accident site coordinates in one of the onboard GPS receivers prior to the flight. He said that after departure, he pushed the "direct" button on the receiver and then proceeded directly to the accident site. However, he was not aware that there was an IPS system installed on the helicopter and that his entire flight had been recorded. When asked why he flew the non-direct route that was recorded by the IPS, he stated that he did not recall that part of the flight, but did recall that the crew was more familiar with the area than he was, and that