History of Flight
At about 1426 eastern standard time on December 31, 2010, a Cessna 172H (N2876L) and a Eurocopter EC-135-P2 (N312PH) collided in midair approximately half a mile northwest of Shenandoah Valley Regional Airport (SHD) in Weyers Cave, Virginia. The airplane departed controlled flight after its right wing separated and was destroyed by impact forces. The helicopter sustained minor damage and landed safely at SHD.
The airplane, operated by an individual, departed SHD at 1402 for a local personal flight. The helicopter, operated by PHI Inc. as AirCare 5, departed the University of Virginia Medical Center in Charlottesville, Virginia, about 1410 for a positioning flight. Both flights were conducted under Title 14 Code of Federal Regulations Part 91 in visual meteorological conditions.
The helicopter crew reported monitoring the common traffic advisory frequency (CTAF) and visually acquiring two aircraft in a left-hand traffic pattern for runway 23. The helicopter's Skywatch traffic collision avoidance device (TCAD) also displayed those aircraft. The accident airplane was operating in the airport traffic area but not in the established pattern. The TCAD did not alert the helicopter crew to the accident airplane.
Witnesses described the helicopter overtaking the airplane from behind, barely touching it, after which the airplane's right wing separated and the airplane nosedived to the ground. One witness noted that the airplane was on the west side of the runway, which was unusual as other traffic flew left traffic patterns.
Radar data showed the helicopter's track consistent with crew statements. The airplane had departed via a right downwind departure, contrary to standard left traffic. Its transponder was off initially and later appeared as a VFR 1200 code. The airplane's last radar target was north of the airport at 500 feet agl, on a track toward the west side of runway 23. About 25 seconds later, the helicopter passed northeast of the airport at about 1,500 feet agl and turned parallel to the runway on the west side. Radar data accounted for all known traffic and the proximity of the two aircraft at collision time.
Personnel Information
The airplane pilot held a commercial pilot certificate with single-engine, multi-engine, and instrument ratings, as well as a flight instructor certificate. His most recent FAA first-class medical certificate was issued June 23, 2010, reporting 2,300 total flight hours. The airplane passenger held no FAA certificates; a logbook bearing his name reflected 7 total flight hours.
The helicopter pilot held an airline transport pilot certificate (multi-engine land) and a commercial pilot certificate (rotorcraft-helicopter, instrument helicopter). His most recent second-class medical certificate was issued October 5, 2010, and he reported 6,803 total flight hours, with about 700 hours in the same make and model as the accident helicopter.
Aircraft Information
The Cessna 172H (N2876L) was manufactured in 1967 and equipped with a Lycoming 145-horsepower reciprocating engine. Its most recent annual inspection was completed November 18, 2010, at 7,366.3 total aircraft hours. The airplane was based at SHD.
The Eurocopter EC-135-P2 (N312PH) was manufactured in 2005 and equipped with two Pratt & Whitney Canada 206B2 turboshaft engines. Its most recent approved aircraft inspection program (AAIP) maintenance inspection was completed December 31, 2010, at 2,209 total aircraft hours. The helicopter was based at SHD.
Meteorological Information
The 1420 weather observation at SHD reported clear skies, wind from 220 degrees at 3 knots, 10 miles visibility, temperature 17°C, dew point 6°C, and an altimeter setting of 30.14 inches of mercury. The sun was at 211 degrees about 22 degrees above the horizon.
Aerodrome Information
SHD was located about 10 miles southeast of Harrisonburg, Virginia, at an elevation of 1,201 feet. It was an uncontrolled airport with runway 5/23 (6,002 feet long, 150 feet wide). The published traffic pattern altitude for piston airplanes was 2,001 feet msl, and the pattern was standard left-hand (no right-pattern designation).
Wreckage and Impact Information
Examination of the airplane wreckage revealed that the right wing separated and was found about 700 feet prior to the main wreckage along an approximate 230-degree path. The main wreckage came to rest inverted and was severely deformed. Multiple dents and paint transfer marks on the airplane matched the helicopter's landing gear skids, indicating a left-rear-to-right-front contact at about 15 degrees. The left side of the vertical stabilizer had a linear scar consistent with the helicopter's skid tubes.
The helicopter sustained only minor damage: the forward left skid tube's "elf shoe" was bent outboard, and both skid tubes and cross tubes had scratches and paint transfers. Paint on the right skid matched the airplane's left vertical stabilizer.
Medical and Pathological Information
Autopsies of both pilots by the Office of the Chief Medical Examiner for Virginia listed the cause of death as "blunt impact injuries." Toxicological testing by the FAA was negative for carbon monoxide, cyanide, and ethanol.
Additional Information
Traffic Advisory System
The helicopter was equipped with an L-3 Avionics SKYWATCH Traffic Advisory System (TAS). The manufacturer determined, based on recorded radar data, that the SKYWATCH would not have generated a traffic alert because the accident airplane did not provide a transponder signal between its second-to-last and last radar target. At the second-to-last target, the airplane was not close enough to trigger an alert.
Visibility Study
The NTSB calculated that as the aircraft converged, the airplane was below the helicopter and at times blocked from view by cockpit structure. From the airplane, the helicopter was likely blocked by the high wing or was above and behind.
Flight Simulation Video
An animation from the helicopter's right seat perspective showed that the airplane became masked by the instrument panel as the helicopter descended, becoming visible only briefly before the collision.
Traffic Pattern and Entry
Federal regulations (FAR 91.126) require airplanes to make left turns in Class G airspace unless markings indicate right turns; helicopters must avoid the flow of fixed-wing aircraft. The Aeronautical Information Manual recommends a 45-degree midfield entry on the downwind leg. The accident airplane was on the upwind (northwest) side of runway 23, below pattern altitude, which was not standard. The airplane's owner and a student both stated that non-standard entry was uncharacteristic of the pilot.
Radar Study
A radar study confirmed that at least three other VFR targets were in the vicinity. The accident airplane's track showed a right downwind departure and a return from the northeast at low altitude. The helicopter approached from the southeast and turned west of the runway. Extrapolation placed both aircraft at the collision site at the same time.
Probable Cause
No probable cause is stated in the source.