Mullinville, KS, USA
N1813
Bell 206-L4
The pilot stated that as he was circling the landing zone, the helicopter felt like it was being "pushed to the northeast and began to shutter." Just as a semi truck passed beneath the helicopter, the pilot stated that the helicopter "went limp" and subsequently the low rotor rpm warning horn activated. The pilot leveled the helicopter from a slight bank and lowered the collective, which silenced the low rotor warning, but the pilot stated that the helicopter "still felt real sluggish." After maneuvering the helicopter away from ground personnel, the helicopter lost power again and the low rotor rpm warning activated a second time. The pilot stated that he set up the helicopter in an autorotative profile and remembers flaring just prior to the initial impact. The pilot stated that he did not lose tail rotor effectiveness. Medical personnel onboard the helicopter stated that during the descent, they noticed power lines and thought that "at out current angle of descent we were going to catch the wires." Several witnesses on the ground stated that as the helicopter passed over the semi truck, it lost control and contacted power lines before impacting the ground. Examination of the wreckage revealed wire damage to the main rotor and tail boom, as well as substantial damage to the fuselage. Further examination of the helicopter disclosed no evidence of any preimpact mechanical anomaly. Weather in the area was reported by local authorities as strong gusty winds.
On August 22, 2007, at 1226 central daylight time, a Bell 206-L4 single-engine air ambulance helicopter, N1813, sustained substantial damage during a hard landing following an impact with power lines while maneuvering near Mullinville, Kansas. The commercial pilot and a medical crewmember sustained serious injuries, and one medical crewmember sustained minor injuries. The helicopter was registered to GM Leasing Company, LLC, Broussard, Louisiana, and operated by Air MD, LLC, Hutchinson, Kansas, doing business as, Midwest LifeTeam. Visual meteorological conditions prevailed, and a company flight plan had been filed for the Title 14 Code of Federal Regulations Part 91 positioning flight. The flight departed Dodge City, Kansas, approximately 1200, and was destined for Mullinville to pick up a patient who had been injured in an automobile accident. According to the pilot's statement, the helicopter was dispatched to respond to an automobile accident on highway 54 in the city limits of Mullinville. The pilot had planned a landing zone (LZ) to the west of the accident on a section of the road between a fire truck and one of the accident vehicles. The pilot circled the LZ to the south when, "the aircraft felt like it was being pushed to the northeast and began to shutter." An eastbound semi-truck passed underneath the helicopter's flight path. At that time the pilot stated that he had a feeling that the helicopter "went limp" and subsequently heard the low rotor rpm warning horn. He then stated, "I immediately leveled the aircraft from a slight bank and lowered the collective and lost the low rotor warning, but the aircraft still felt real sluggish." The helicopter started drifting toward ground personnel and the pilot stated, "I distinctly remember putting in left [rudder] pedal and steering us back to the parallel road which was going to keep us away from the ground personnel, but the aircraft still seemed sluggish and lost power again and I got the low rotor a second time." The pilot said that he set up an autorotative profile and remembers flaring the helicopter prior to the initial impact. During an interview with local authorities, the pilot stated he did not lose tail rotor effectiveness. A paramedic that was onboard the helicopter stated that during the approach, "the aircraft began to shake, vibrate, and lose altitude." The paramedic asked the pilot what was happening, and the pilot replied, "we are alright." The paramedic then noticed that the helicopter was heading for several emergency units located on the ground. After the pilot maneuvered the helicopter away from the emergency vehicles, the paramedic, along with another EMS technician aboard the helicopter, communicated to the pilot that there were power lines "ahead of us, but still beneath our altitude." The paramedic then stated that, "Although I did not hear any sound, I thought that at our current angle of descent were were going to catch the wires." A second medical crewmember on board stated that they "heard a loud popping noise" prior to the accident. Several witness statements taken by the Kansas Highway Patrol stated that after the semi-truck passed under the helicopter's flight path it seemed to lose control and drift into the power lines before it impacted the ground. A Garmin GPSMAP 396 Global Positioning System (GPS) receiver was removed from the helicopter and examined by the National Transportation Safety Board's Vehicle Recorders Division, Washington, D.C. According to a GPS study prepared by a vehicle recorder specialist, the helicopter departed from the northern edge of Dodge City, Kansas at approximately 12:08:04. The GPS track indicated the helicopter reached the LZ site at approximately 12:25:24 on a southerly heading at approximately 250 feet above ground level (agl). The GPS track shows the helicopter make a left hand turn to the south of the LZ in a shallow descent. The track crosses the eastbound lane of highway 54 at approximately 12:26:02 at approximately 90 feet agl on a northeasterly track. The final GPS position for the accident flight was just south of the westbound lane of Highway 54 at approximately 12:26:16. Weather in the Mullinville area at the time of the accident was reported by local authorities as strong gusty winds. The nearest reporting facility to Mullinville is Dodge City, Kansas (DDC), approximately 29 miles northwest of the accident site. The DDC automated weather at 1252 CDT reported the winds out of the south at 15 gusting to 22 knots with clear skies and 10 miles visibility. Examination of the airframe by a Federal Aviation Administration inspector, and representatives of Bell Helicopter and the operator, revealed the main rotor blade showed evidence of a wire stike, a wire was wrapped around the tail rotor, and there were wire marks on the tail boom and horizontal stabilizer. The left skid was collapsed, the main rotor blades impacted the tail boom, and the fuselage was partially crushed. Flight control continuity was established for all flight controls. The engine was removed and shipped to the Rolls-Royce Corporation, Indianapolis, Indiana for further inspection. A teardown inspection of the engine was performed on November 7, 2007, under the supervision of the NTSB investigator-in-charge (IIC). Visual inspection of the engine exterior revealed no evidence of damage or anomaly. Engine run testing, including steady state and power transient operation, timed accelerations and decelerations, and governor droop resulted in the engine meeting all specification points. At the time of the accident the engine had accumulated 465.6 total hours and 619 cycles since new.
The pilot's failure to maintain main rotor rpm resulting in an uncontrolled descent, collision with transmission wires, and a hard landing. A contributing factor was the tranmission wires.
Source: NTSB Aviation Accident Database
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