Relience, TN, USA
N484AE
BELL 206
Before landing, the pilot performed a high and low reconnaissance of the area and received a briefing of the obstacles by the landing zone. The crew was advised of wires along the road north of the field and large rolls of hay spaced intermittently across the field. The pilot then landed the helicopter in a field and picked up a patient who had been involved in a motor vehicle accident. Given the weight of the helicopter and power available, the pilot elected to perform an airspeed-over-altitude takeoff on a westerly departure path along the long axis of the landing zone. The departure path was signaled to the landing zone commander, who issued an approval for the takeoff. During the initial takeoff climb, the helicopter struck wires and returned to the field for landing. After the incident, a closer inspection of the takeoff path revealed that a three-strand group of wires crossed the west side of the field perpendicular to the takeoff path. When viewed from the point of departure, the wires appeared to emanate from the thick, tall tree lines that bordered both sides of the landing zone, and were superimposed against a background of dense woods. There were no additional visual cues (poles, towers, or transformers) available that could be associated with the wires. Additionally, at the time of the accident, the sun was directly in the takeoff path and 30 degrees above the horizon. The bright sunlight and glare conditions likely reduced the ability of ground crew and the flight crew to discern wire obstacles.
HISTORY OF FLIGHT On August 1, 2011, about 1818 eastern daylight time, a Bell 206 L4 helicopter, N484AE, operated by Air Evac EMS, Inc., sustained minor damage from a wire strike during takeoff in Reliance, Tennessee. The certificated commercial pilot, two crewmembers and one patient were not injured. Visual meteorological conditions prevailed, and a company flight plan was filed for the flight that departed a farm field in wooded, hilly terrain. The medical evacuation flight was conducted under the provisions of 14 CFR Part 135, and destined for Erlanger Medical Center Heliport (0TN8), Chattanooga, Tennessee. In a written statement, the pilot stated that the purpose of the flight was to pick up a patient that had been involved in a motor vehicle accident. The landing zone (LZ) was a large field where he performed an approach after performing a "high and low recon" of the area, and receiving a briefing of the obstacles by the "LZ command" that was established by the local fire department. The crew was advised of wires along the road north of the field, and large rolls of hay spaced intermittently across the field. After he determined the weight of the helicopter and power available, the pilot decided on an "airspeed over altitude" takeoff. The pilot chose a westerly departure path because the field offered a "long, open area with down-sloping terrain." The departure path was signaled to the LZ commander, who issued approval for the takeoff through a firefighter. The pilot initiated the takeoff, and when the helicopter reached 50 feet and 40 knots, the pilot adjusted the flight controls for a 60-knot climb. About that time, the pilot heard a loud "thud" and saw scuff marks on the windscreen that alerted him to the wire strike. He announced the emergency to his crew, and completed a precautionary landing back to the field. Written statements provided by both crewmembers were consistent with the pilot's. On August 2, 2011, a Federal Aviation Administration (FAA) aviation safety inspector visited the site, and photographed the area. Damage to the helicopter was limited to the windscreen, and no major structural damage was noted. Scratches in the paint and marks on the upper and lower Wire Strike Protection System (WSPS) were consistent with a wire strike. The inspector observed that a three-strand group of wires crossed the west side of the field perpendicular to the takeoff path. When viewed from the point of departure, the wires appeared out of the thick, tall tree lines that bordered both sides of the LZ, and were superimposed against a background of dense woods. There were no additional visual cues (poles, towers, or transformers) available that could be associated with the wires. PERSONNEL INFORMATION The pilot held a commercial pilot certificate with ratings for rotorcraft helicopter and instrument helicopter. He reported 2,173 total hours of flight experience, of which 116 were in the incident helicopter make and model. His most recent FAA second-class medical certificate was issued on June 1, 2011. AIRCRAFT INFORMATION According to FAA records, the helicopter was manufactured in 2010. The most recent inspection in the helicopter Approved Aircraft Inspection Program (AAIP) was completed July 27, 2011, at 564 total aircraft hours. METEOROLOGICAL INFORMATION At 1853, the weather conditions reported at Lovell Field, Chattanooga, Tennessee, located approximately xx miles xx of the incident site, included few clouds at 6,500 feet, visibility 10 miles, temperature 36 degrees C, dew point 15 degrees C, and an altimeter setting of 29.93 inches of mercury. The wind was from 120 degrees at 6 knots. The calculated density altitude at the time of the incident was 3,318 feet. According to the U.S. Naval Observatory, at the time of the incident the azimuth of the sun was about 273 degrees east of north, and the sun was positioned approximately 28 degrees above the horizon.
Inadvertent contact with wires due to the lack of visual cues regarding their presence and the low angle of the sun, which was directly in the takeoff path.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
