History of Flight
On April 29, 2014, at 2355 Pacific daylight time, an Airplane Factory Sling, registration N511NG, impacted mountainous terrain approximately 5 miles southwest of Barstow-Daggett Airport in Daggett, California. The aircraft was operated by the Sling Flying Club under 14 Code of Federal Regulations Part 91 as an instructional flight. The certified flight instructor sustained serious injuries, and the sport pilot being instructed received minor injuries. Night visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from Torrance, California, about 2130.
The sport pilot reported that while approximately 10 miles southwest of the airport, they could clearly see the airport lights. They had begun a descent from 5,500 feet mean sea level (msl) and were planning their entry into the traffic pattern when the airplane suddenly impacted terrain twice before coming to a full stop. The sport pilot secured the electrical equipment and fuel system, egressed, attended to the CFI, and called for assistance using a mobile phone.
The automated surface observing system at Daggett recorded at 2350 clear skies, visibility 10 miles, and wind from 260 degrees at 3 knots. Astronomical data indicated moon set had occurred at 2019, resulting in dark night conditions over the sparsely populated high desert area.
Wreckage and Impact Information
The airplane came to rest on its belly on a downhill slope on the east side of a ridge, with the sloping desert terrain descending about 2,000 feet to the desert floor. The landing gear separated from the airframe during the initial collision with the ridge line. The wings, engine, and tail remained fully attached to the fuselage. The wreckage was recovered and transported to a secure facility in Phoenix, Arizona for further examination.
On May 13, 2014, the NTSB Investigator-in-Charge examined the wreckage. The fuselage was placed on a stand with the wings and engine previously removed for transportation. Flight control continuity was established from the cockpit to the ailerons, elevator, and rudder. The flaps were in the retracted position. Leading edges of both wings exhibited damage; the inboard section of the right wing showed hydraulic deformation along the front of the fuel tank. Engine control cables were traced to the firewall, where they had been cut by recovery personnel.
The aircraft was equipped with two MLG Avionics Stratomaster Voyager Electronic Flight Information System (EFIS) displays, one in front of each seat. When power was applied, the left display powered up but its control buttons were damaged and nonfunctional. The right display powered up with functional buttons; it was in night mode, which was changed to day mode for easier viewing. Review of menus revealed that the Terrain Warning box was unchecked, while the Collision Warning box was checked.
Visual examination of the engine showed no holes in the case, no oil leaks, all four cylinders attached, and exhaust and induction manifolds in place. The propeller hub was attached to the crankshaft flange. Top spark plugs were removed; all exhibited light gray electrodes with no mechanical damage, consistent with normal operation per the Champion Check-A-Plug chart. The crankshaft rotated by hand achieved thumb compression on all cylinders, with valve rockers moving in concert. Both carburetor bowls were removed; each contained undamaged floats, but no fuel was present. The propeller was a Whirlwind 3-bladed composite type; two blades remained attached to the hub, and all three blades showed leading edge damage.
Examination of the cockpit shoulder harnesses revealed that the anchor cables for both pilot positions had separated due to overload. Documentation of the cable separation was provided to the airplane manufacturer, who subsequently updated the design and specified a larger diameter cable for the shoulder harness anchor points.