Accident Details
On April 13, 2014, about 1542 eastern daylight time, an Aircraft Industries a.s. L33 SOLO glider, registration N318BA, collided with terrain approximately 400 feet north-northeast of Crooked Creek Airport (7NC5) in Bunn, North Carolina. The private pilot sustained serious injuries, and the glider was substantially damaged. The glider was registered to and operated by the North Carolina Soaring Association under 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from 7NC5 about 1525 EDT.
The pilot was towed aloft from runway 22 and released at approximately 2,000 feet mean sea level at a point approximately just over 1 mile northwest of the airport. The tow plane returned and landed. Shortly thereafter, the tow plane pilot stated that the accident pilot reported he was returning to the airport. The tow plane pilot asked if he wanted another tow, and the pilot replied affirmatively.
Witness Observations
Witnesses at the airport reported hearing the pilot announce he was entering the traffic pattern for a right downwind for runway 22. They noted the glider was abeam the approach end of runway 22 but appeared low. The glider turned onto base leg, where trees obscured one witness's view. Another witness saw the glider through the trees in a nose-low angle greater than 50 degrees, then observed what appeared to be the wings rotating as if in a ground loop at a higher angle. The witnesses heard an impact and ran to the site, where they found the pilot being attended to by nearby homeowners. Fire rescue responded, and the pilot was transported by ambulance to a fire station, then airlifted to a hospital for treatment.
Flight Data and GPS Analysis
The accident site was located at 35°56'05"N, 078°14'32"W, about 450 feet and 34 degrees from the approach end of runway 22. The wing was separated from the attach points of the fuselage, but the two pins securing each wing were in place. Postaccident inspection by the Federal Aviation Administration (FAA) and the Chief Tow Pilot revealed no evidence of preimpact failure or malfunction of the flight controls for roll, pitch, yaw, and air brakes. The FAA inspector reported the air brakes in the wings were retracted, though the position of the air brake handle at impact could not be determined. The right wingtip was bent up, and the left wing leading edge was crushed aft.
A portable GPS receiver was removed from the glider and sent to the NTSB Vehicle Recorder Division for readout. The data downloaded successfully, showing four sessions on the accident date, including the accident flight. The data indicated numerous heading changes after the tow. Between 1541:20 and 1541:35, the glider was north of the airport flying eastward consistent with a base leg, slowing from 53 to 32 knots. The glider then flew southward toward the airport, and between 1541:53 and 1541:57, it turned slightly right, with groundspeed decreasing from 34 to 25 knots. The last recorded GPS point at 1541:57 was at 35.93588°N, -78.2427°W, about 450 feet and 163 degrees from the accident site.
According to the Type Certificate Data Sheet, the empty weight of the glider was approximately 463 pounds. The pilot's weight per his last medical application (October 16, 2013) was 219 pounds, giving an approximate gross weight at the time of the accident of 682 pounds. The Flight Manual recommends an approach speed of 49 knots indicated airspeed (KIAS) with air brakes retracted; the stall speed at that weight is about 34 KIAS. An aviation surface observation at Triangle North Executive Airport (LHZ) at 1535, about 7 minutes before the accident, indicated wind from 160 degrees at 11 knots gusting to 15 knots, visibility 10 statute miles, scattered clouds at 5,500 and 7,000 feet, temperature 25°C, dew point 13°C, and altimeter setting 30.13 inHg. The accident site was about 7 nautical miles and 142 degrees from LHZ.