ERA11FA101

The inherent limitations of the see-and-avoid concept, which made it difficult for the helicopter pilot to see the airplane before the collision. Contributing to the accident was the airplane pilot’s non-standard entry to the airport traffic pattern, which, contrary to published Federal Aviation Administration guidance, was conducted 500 feet below the airport's published traffic pattern altitude and in a direction that conflicted with the established flow of traffic.

Aircraft 1 The pilot and both crewmembers of the helicopter recalled routine radio communication as the helicopter approached the destination airport. They established visual contact with two airplanes that had announced their positions in the traffic pattern; one on the downwind leg and one on short final. The airplanes were also identified by the traffic avoidance system onboard the helicopter. The pilot followed behind and north of the second airplane and continued to the west side of the airport to complete a landing at the helipad. During the descent, about 500 feet above ground level (agl), the pilot "saw about 2 feet of white wing right outside." He "pulled power" and then felt contact with an airplane. The airplane's right wing separated before it departed controlled flight and descended to the ground, fatally injuring both occupants. The helicopter subsequently landed with minor damage and no injuries to the 3 occupants. Interpolation of radar data revealed that the accident airplane departed from the same airport about 21 minutes prior to the accident and completed a right downwind departure, contrary to the established left traffic pattern. The airplane’s transponder appeared to be off for about 3 minutes after takeoff before transmitting the visual flight rules transponder code (1200) for the remainder of the observed flight; the transponder appeared to be on and functioning at the time of the collision. The airplane proceeded north of the airport before reversing course and returning to approach the airport from the northeast. The last target was observed about 1.2 nautical miles north of the airport on a track leading toward the west side of the landing runway at an altitude of 500 feet agl. About 25 seconds later, the helicopter passed northeast of the airport on a modified left base, about 500 feet above traffic pattern altitude (1,500 feet agl), crossed the final approach course, and turned parallel to and on the west side of the runway. Although only the helicopter was observed by radar at the time of the collision, extrapolation of the accident airplane’s previously observed targets and flight path placed the airplane at the accident site about the same time the helicopter was observed there. An analysis of the relative positions of the airplane and helicopter based on radar data indicated that the airplane remained below the helicopter pilot's field of view as the helicopter overtook the airplane from behind and descended upon it from above. Although the data indicated that the airplane would likely have been visible to the pilot of the helicopter, it is important to note that the onboard traffic avoidance system (TAS) did not provide the pilot with any alert of its presence because the system operated on line-of-sight principles. If an intruder aircraft’s antenna was shielded from the TAS antenna, the ability of the TAS to track the target would be affected. If a TAS equipped aircraft was located directly above an intruder, the airframe of one or both of the aircraft could cause the TAS’s interrogations to be shielded, depending on antenna location (either bottom or top-mounted). All other airplanes in the traffic pattern were acquired visually by the pilot and crew as their positions were confirmed by the helicopter's onboard traffic avoidance system and the position reports provided by the pilots of each airplane. Because of the high-wing structure of the airplane, and its relative position and altitude, the helicopter's image was either blocked from the airplane pilot's view by the left wing, or was above and behind the airplane in the seconds before collision. Further, no radio position reports from the accident airplane were confirmed. The helicopter pilot’s unalerted detection of the airplane against a complex background of ground objects would have been difficult because of both the lack of apparent contrast between the airplane and the ground, its size in the windscreen, its relative lack of movement within the pilot’s field of view, and the position and angle of the sun. In addition, the helicopter pilot’s familiarity with the customary routes used by fixed-wing pilots to fly into and out of the airport also made detection of the airplane less likely, because the airplane was not in a location that normally contained conflicting traffic. Finally, before the helicopter turned and overtook the airplane, the helicopter pilot’s visual attention would have likely been directed toward the landing area, which would also have limited opportunities for detection of the airplane. The airplane's departure and arrival were contrary to published Federal Aviation Administration guidance, the airplane owner's guidance, and the airplane pilot's guidance to his own students with regard to pattern entry at the destination airport. --- Aircraft 2 The pilot and both crewmembers of the helicopter recalled routine radio communication as the helicopter approached the destination airport. They established visual contact with two airplanes that had announced their positions in the traffic pattern; one on the downwind leg and one on short final. The airplanes were also identified by the traffic avoidance system onboard the helicopter. The pilot followed behind and north of the second airplane and continued to the west side of the airport to complete a landing at the helipad. During the descent, about 500 feet above ground level (agl), the pilot "saw about 2 feet of white wing right outside." He "pulled power" and then felt contact with an airplane. The airplane's right wing separated before it departed controlled flight and descended to the ground, fatally injuring both occupants. The helicopter subsequently landed with minor damage and no injuries to the 3 occupants. Interpolation of radar data revealed that the accident airplane departed from the same airport about 21 minutes prior to the accident and completed a right downwind departure, contrary to the established left traffic pattern. The airplane’s transponder appeared to be off for about 3 minutes after takeoff before transmitting the visual flight rules transponder code (1200) for the remainder of the observed flight; the transponder appeared to be on and functioning at the time of the collision. The airplane proceeded north of the airport before reversing course and returning to approach the airport from the northeast. The last target was observed about 1.2 nautical miles north of the airport on a track leading toward the west side of the landing runway at an altitude of 500 feet agl. About 25 seconds later, the helicopter passed northeast of the airport on a modified left base, about 500 feet above traffic pattern altitude (1,500 feet agl), crossed the final approach course, and turned parallel to and on the west side of the runway. Although only the helicopter was observed by radar at the time of the collision, extrapolation of the accident airplane’s previously observed targets and flight path placed the airplane at the accident site about the same time the helicopter was observed there. An analysis of the relative positions of the airplane and helicopter based on radar data indicated that the airplane remained below the helicopter pilot's field of view as the helicopter overtook the airplane from behind and descended upon it from above. Although the data indicated that the airplane would likely have been visible to the pilot of the helicopter, it is important to note that the onboard traffic avoidance system (TAS) did not provide the pilot with any alert of its presence because the system operated on line-of-sight principles. If an intruder aircraft’s antenna was shielded from the TAS antenna, the ability of the TAS to track the target would be affected. If a TAS-equipped aircraft was located directly above an intruder, the airframe of one or both of the aircraft could cause the TAS’s interrogations to be shielded, depending on antenna location (either bottom or top-mounted). All other airplanes in the traffic pattern were acquired visually by the pilot and crew as their positions were confirmed by the helicopter's onboard traffic avoidance system and the position reports provided by the pilots of each airplane. Because of the high-wing structure of the airplane, and its relative position and altitude, the helicopter's image was either blocked from the airplane pilot's view by the left wing, or was above and behind the airplane in the seconds before collision. Further, no radio position reports from the accident airplane were confirmed. The helicopter pilot’s unalerted detection of the airplane against a complex background of ground objects would have been difficult because of both the lack of apparent contrast between the airplane and the ground, its size in the windscreen, its relative lack of movement within the pilot’s field of view, and the position and angle of the sun. In addition, the helicopter pilot’s familiarity with the customary routes used by fixed-wing pilots to fly into and out of the airport also made detection of the airplane less likely, because the airplane was not in a location that normally contained conflicting traffic. Finally, before the helicopter turned and overtook the airplane, the helicopter pilot’s visual attention would have likely been directed toward the landing area, which would also have limited opportunities for detection of the airplane. The airplane's departure and arrival were contrary to published Federal Aviation Administration guidance, the airplane owner's guidance, and the airplane pilot's guidance to his own students with regard to pattern entry at the destination airport.

Aircraft 1 HISTORY OF FLIGHT On December 31, 2010, about 1426 eastern standard time, a Eurocopter EC-135-P2 helicopter, N312PH, operated by PHI Inc., as AirCare 5, and a Cessna 172H, N2876L, collided in midair approximately 1/2 mile northwest of the Shenandoah Valley Regional Airport (SHD), Weyers Cave, Virginia. The airplane departed controlled flight after the right wing separated, and was destroyed by impact forces at ground contact. The helicopter sustained minor damage and landed safely at SHD. The certificated commercial pilot and passenger on board the airplane were fatally injured. The certificated commercial pilot and two medical flight crewmembers on board the helicopter were not injured. Visual meteorological conditions prevailed for the airplane's local personal flight that originated from SHD, at 1402, and for the helicopter’s positioning flight that originated from the University of Virginia Medical Center (8VA5), Charlottesville, Virginia, about 1410. A company flight plan was filed for the helicopter positioning flight, and no flight plan was filed for the airplane flight. Both flights were conducted under the provisions of Title 14 Code of Federal Regulations Part 91. All three crewmembers aboard the helicopter were interviewed at the scene, and their statements were consistent throughout. They described departing 8VA5 after completing a patient drop-off, crossing "the ridgeline" at 4,500 feet, and approaching SHD from the east. They each described monitoring the common traffic advisory frequency (CTAF), and how the announced traffic, two aircraft established in a left-hand traffic pattern for runway 23, were acquired both visually and on the helicopter's Skywatch traffic collision avoidance device (TCAD) system. The two crewmembers in the front seats correlated the landing-pattern traffic's announced positions both visually and on the TCAD. The third, aft-seated crewmember visually acquired the landing traffic based on their announced positions. The accident airplane was operating in the airport traffic area, but not in the established traffic pattern. One flight nurse rode on the left side of the helicopter, behind the copilot's station, and faced aft. She stated that she was aware of two airplanes in the traffic pattern, one on "short final," the second airplane behind, and that the helicopter would be "the third aircraft to land." According to the flight nurse, "I was in the back under sterile cockpit procedures. Everyone was 'eyes-out' looking for traffic. I felt a bump and a shudder and the pilot said, 'What was that?'" She looked out and saw a white rectangle under the helicopter for "less than a millisecond." A second flight nurse who rode in the copilot (left) seat gave a similar account, and stated that he had visual contact with the two airplanes that were also displayed on the helicopter's TCAD device. He added, "We were talking to all of them." The helicopter was in a gradual descent, and the nurse had visual contact with the airplanes on the base and final legs of the traffic pattern when he felt a bump. He reported that he never saw anything outside the helicopter at the time he felt the bump. The pilot recalled routine radio communication as the helicopter approached SHD, as well as a radio call to request fuel upon landing. He described two airplanes in the traffic pattern: one on the downwind leg, and one on short final. The pilot followed behind and north of the second airplane and continued to the west side of the airport to complete a landing at the west side helipad. During the descent, about 500 feet above ground level, the pilot "saw about 2 feet of white wing right outside." He "pulled power" and then felt the contact. All three crewmembers stated that the TCAD did not alert them to the accident airplane. They all described the crew coordination efforts to assess the damage to their aircraft, and the completion of a safe landing at the west-side helipad. Witness interviews and written statements provided were largely consistent throughout. The witnesses were familiar with the airport, and with what they described as the usual traffic pattern of aircraft around the airport. Most of the witnesses described their vantage points as being 90 degrees from the direction of flight for both accident aircraft, and that the aircraft were traveling from roughly north to south. Most described the aircraft in level flight, with some differences as to whether the helicopter was on the airplane's left or right. Both aircraft were described as being "lower than usual," "awfully close," "almost even…next to each other." Consistently, witnesses described the helicopter as it overtook the airplane from behind, "barely touching" the airplane, and then watching as the right wing departed the airplane, and the remainder of the airplane "nose-dived" to ground contact. In a written statement he provided along with photographs, one witness described the airplane as it approached the airport on the west side of the runway, and the helicopter's descent until the two aircraft collided. He added, "When I saw the airplane on the west side of the runway I found it kind of strange that it was there due to the fact that all the other airplanes were flying a left traffic pattern. I honestly had no idea why it was on this side of the runway. If it was trying to fly a right traffic pattern - it was going the wrong way." In interviews with a Federal Aviation Administration (FAA) aviation safety inspector, pilots operating in the traffic pattern at SHD around the time of the accident said they recalled hearing various radio calls with regards to departures to the northwest, "maneuvering 6 miles to the northwest," and hearing the accident helicopter announce its position as it approached SHD. One pilot said he recalled hearing an airplane announce entering "upwind for runway 23" at SHD. All of the pilots stated that the traffic pattern at SHD was "unusually busy" around the time of the accident. A pilot operating in the local flying area at the time of the accident said he had 15 hours of flight instruction from the pilot of the accident airplane, and that he would likely have recognized the instructor's voice over the radio had he heard it. He added that he distinctly recalled 3 separate position reports from the helicopter as it approached SHD, and standard traffic calls from airplanes in left traffic at SHD. He did not recall hearing a radio call that announced a non-standard entry, but added that the frequency was crowded on the day of the accident. Radar data identified the accident helicopter by its assigned transponder code. The helicopter's ground track and altitudes were consistent with crewmember descriptions. The other radar targets were all depicted with the visual flight rules (VFR) "1200" transponder code. The number of airplanes that these "VFR targets" represented could not be reconciled. PERSONNEL INFORMATION A review of Federal Aviation Administration (FAA) airman records revealed that the pilot in the airplane held a commercial pilot certificate with ratings for airplane single-engine land, airplane multiengine, and instrument airplane. He held a flight instructor certificate with ratings for airplane single-engine, multiengine land, and instrument airplane. His most recent FAA first-class medical certificate was issued June 23, 2010, at which time he reported 2,300 total hours of flight experience. The passenger on board the airplane held no FAA certificates. However, a pilot logbook bearing his name was recovered and reflected 7 total hours of flight experience logged. The pilot of the helicopter held an airline transport pilot certificate with a rating for airplane multiengine land, and a commercial pilot certificate with ratings for rotorcraft - helicopter and instrument helicopter. His most recent FAA second-class medical certificate was issued October 5, 2010. The pilot reported 6 --- Aircraft 2 HISTORY OF FLIGHT On December 31, 2010, about 1426 eastern standard time, a Eurocopter EC-135-P2 helicopter, N312PH, operated by PHI Inc., as AirCare 5, and a Cessna 172H, N2876L, collided in midair approximately 1/2 mile northwest of the Shenandoah Valley Regional Airport (SHD), Weyers Cave, Virginia. The airplane departed controlled flight after the right wing separated, and was destroyed by impact forces at ground contact. The helicopter sustained minor damage and landed safely at SHD. The certificated commercial pilot and passenger on board the airplane were fatally injured. The certificated commercial pilot and two medical flight crewmembers on board the helicopter were not injured. Visual meteorological conditions prevailed for the airplane's local personal flight that originated from SHD, at 1402, and for the helicopter’s positioning flight that originated from the University of Virginia Medical Center (8VA5), Charlottesville, Virginia, about 1410. A company flight plan was filed for the helicopter positioning flight, and no flight plan was filed for the airplane flight. Both flights were conducted under the provisions of Title 14 Code of Federal Regulations Part 91. All three crewmembers aboard the helicopter were interviewed at the scene, and their statements were consistent throughout. They described departing 8VA5 after completing a patient drop-off, crossing "the ridgeline" at 4,500 feet, and approaching SHD from the east. They each described monitoring the common traffic advisory frequency (CTAF), and how the announced traffic, two aircraft established in a left-hand traffic pattern for runway 23, were acquired both visually and on the helicopter's Skywatch traffic collision avoidance device (TCAD) system. The two crewmembers in the front seats correlated the landing-pattern traffic's announced positions both visually and on the TCAD. The third, aft-seated crewmember visually acquired the landing traffic based on their announced positions. The accident airplane was operating in the airport traffic area, but not in the established traffic pattern. One flight nurse rode on the left side of the helicopter, behind the copilot's station, and faced aft. She stated that she was aware of two airplanes in the traffic pattern, one on "short final," the second airplane behind, and that the helicopter would be "the third aircraft to land." According to the flight nurse, "I was in the back under sterile cockpit procedures. Everyone was 'eyes-out' looking for traffic. I felt a bump and a shudder and the pilot said, 'What was that?'" She looked out and saw a white rectangle under the helicopter for "less than a millisecond." A second flight nurse who rode in the copilot (left) seat gave a similar account, and stated that he had visual contact with the two airplanes that were also displayed on the helicopter's TCAD device. He added, "We were talking to all of them." The helicopter was in a gradual descent, and the nurse had visual contact with the airplanes on the base and final legs of the traffic pattern when he felt a bump. He reported that he never saw anything outside the helicopter at the time he felt the bump. The pilot recalled routine radio communication as the helicopter approached SHD, as well as a radio call to request fuel upon landing. He described two airplanes in the traffic pattern: one on the downwind leg, and one on short final. The pilot followed behind and north of the second airplane and continued to the west side of the airport to complete a landing at the west side helipad. During the descent, about 500 feet above ground level, the pilot "saw about 2 feet of white wing right outside." He "pulled power" and then felt the contact. All three crewmembers stated that the TCAD did not alert them to the accident airplane. They all described the crew coordination efforts to assess the damage to their aircraft, and the completion of a safe landing at the west-side helipad. Witness interviews and written statements provided were largely consistent throughout. The witnesses were familiar with the airport, and with what they described as the usual traffic pattern of aircraft around the airport. Most of the witnesses described their vantage points as being 90 degrees from the direction of flight for both accident aircraft, and that the aircraft were traveling from roughly north to south. Most described the aircraft in level flight, with some differences as to whether the helicopter was on the airplane's left or right. Both aircraft were described as being "lower than usual," "awfully close," "almost even…next to each other." Consistently, witnesses described the helicopter as it overtook the airplane from behind, "barely touching" the airplane, and then watching as the right wing departed the airplane, and the remainder of the airplane "nose-dived" to ground contact. In a written statement he provided along with photographs, one witness described the airplane as it approached the airport on the west side of the runway, and the helicopter's descent until the two aircraft collided. He added, "When I saw the airplane on the west side of the runway I found it kind of strange that it was there due to the fact that all the other airplanes were flying a left traffic pattern. I honestly had no idea why it was on this side of the runway. If it was trying to fly a right traffic pattern - it was going the wrong way." In interviews with a Federal Aviation Administration (FAA) aviation safety inspector, pilots operating in the traffic pattern at SHD around the time of the accident said they recalled hearing various radio calls with regards to departures to the northwest, "maneuvering 6 miles to the northwest," and hearing the accident helicopter announce its position as it approached SHD. One pilot said he recalled hearing an airplane announce entering "upwind for runway 23" at SHD. All of the pilots stated that the traffic pattern at SHD was "unusually busy" around the time of the accident. A pilot operating in the local flying area at the time of the accident said he had 15 hours of flight instruction from the pilot of the accident airplane, and that he would likely have recognized the instructor's voice over the radio had he heard it. He added that he distinctly recalled 3 separate position reports from the helicopter as it approached SHD, and standard traffic calls from airplanes in left traffic at SHD. He did not recall hearing a radio call that announced a non-standard entry, but added that the frequency was crowded on the day of the accident. Radar data identified the accident helicopter by its assigned transponder code. The helicopter's ground track and altitudes were consistent with crewmember descriptions. The other radar targets were all depicted with the visual flight rules (VFR) "1200" transponder code. The number of airplanes that these "VFR targets" represented could not be reconciled. PERSONNEL INFORMATION A review of Federal Aviation Administration (FAA) airman records revealed that the pilot in the airplane held a commercial pilot certificate with ratings for airplane single-engine land, airplane multiengine, and instrument airplane. He held a flight instructor certificate with ratings for airplane single-engine, multiengine land, and instrument airplane. His most recent FAA first-class medical certificate was issued June 23, 2010, at which time he reported 2,300 total hours of flight experience. The passenger on board the airplane held no FAA certificates. However, a pilot logbook bearing his name was recovered and reflected 7 total hours of flight experience logged. The pilot of the helicopter held an airline transport pilot certificate with a rating for airplane multiengine land, and a commercial pilot certificate with ratings for rotorcraft - helicopter and instrument helicopter. His most recent FAA second-class medical certificate was issued October 5, 2010. The pilot reported 6