History of Flight
On February 10, 2016, at 1617 Pacific standard time, a Flight Design CTLS airplane, registration N911TS, impacted terrain 4 miles southwest of Springville, California. The airplane was operating under 14 Code of Federal Regulations Part 91 as a public aircraft for the Tulare County Sheriff. It had departed Visalia Municipal Airport at approximately 1446 for a local flight. Visual meteorological conditions prevailed.
Witnesses observed the airplane circling at low altitude before departing southwest. The airplane made a left turn, wings dipped left and right, then descended into the ground in a sideways wing-down orientation. The engine was heard at a steady tone until impact. A post-crash fire destroyed the airplane.
Personnel Information
The pilot, age 45, held an Airline Transport Pilot certificate (issued October 11, 2007) with multiengine land, commercial single-engine land, rotorcraft helicopter, and instrument helicopter ratings, plus glider private privileges. He also held a flight instructor certificate for single-engine land (issued June 29, 2014) and a first-class medical certificate (April 2, 2014) with no limitations. His civilian logbook showed 3,675 total hours, 3,526.4 in single-engine airplanes, and 1,002.6 hours in the Flight Design CTLS. His most recent flight review was December 8, 2015.
The passenger was a Sheriff Deputy with about 27 years of service, assigned to the air unit for about a year, acting as an observer and camera operator.
Aircraft Information
The two-seat, high-wing, fixed-gear airplane (serial number F-11-02-05) was manufactured in 2011 and powered by a Rotax 912ULS 100-hp engine with a Sensenich 3-bladed ground-adjustable propeller. The last 100-hour inspection was on February 3, 2016, at a total aircraft time of 3,103.9 hours and total engine time of 1,103.9 hours.
The aircraft was configured for aerial observation with additional equipment including a FM transceiver, mini PC, GNSS receiver, camera system, and spotlight. The most recent weight and balance (August 27, 2015) documented an empty weight plus 90 kg fuel at 511 kg. Two crew, personal gear, and survival kit added 175.5 kg, giving a takeoff weight of 686.5 kg—exceeding the maximum gross weight of 600 kg stated in the pilot operating handbook. The calculated CG (0.448 m) was within limits (forward 0.282 m, aft 0.478 m). After 90 minutes of flight, estimated fuel burn of 16.4 kg reduced aircraft weight to 669.6 kg.
Stall speeds from the pilot operating handbook: at 600 kg, flaps 0°, stall speed 42 kcas. Using AC 23-8C formula for the accident weight (669.6 kg), corrected zero-flap stall speed is 44.4 kcas. At 15° bank, stall speed increases to 45.3 kcas; at 30° bank, 47.6 kcas; at 45° bank, 52.7 kcas.
Meteorological Information
At 1556, Porterville AWOS-3 (11 miles southwest, elevation 443 ft) reported wind from 300° at 8 knots, visibility 10 statute miles, sky clear, altimeter 30.18 inHg. Nearby radar indicated winds below 7 knots from northwest to north-northwest. A model sounding at 1600 PST showed wind from about 290° true at 3–4 knots at 1,600 ft msl. At accident time (1617), the sun azimuth was 241° true, elevation 13°. A pilot flying near the area noted heavy haze and difficulty distinguishing terrain due to sun glare.
Aids to Navigation
A Garmin GPSMAP 496 portable GPS recovered from the wreckage provided track data. The accident flight began at 1446:36 PST and ended at 1614:11. After departure, the aircraft orbited near Ivanhoe, made a touch-and-go at Woodlake Airport, and proceeded generally north then south. At 1601 it orbited near Lake Success. The final recorded positions: at 1613:47 heading 249° true, then left turn, last fix at 1614:11 with heading 114.8° true, GPS altitude 1,096 ft (400 ft agl), groundspeed 52 knots.
Wreckage and Impact Information
The wreckage was on a steep 20° slope with grass and rocks. The debris field was 80 ft long on a 010° magnetic bearing. The airplane was inverted, nose pointing 190° magnetic. Post-crash fire consumed the structure, leaving carbon fiber remnants. Initial impact marks included left main gear tire and left wing tip indentations, and a disturbed area with fiberglass fragments. The impact was consistent with high vertical energy and little forward velocity.
Control system components were examined: aileron push rods were mostly destroyed; rudder cables remained attached; elevator push-pull cable was separated at the cockpit end with an overload fracture. The horizontal stabilator was partially fire-damaged; vertical stabilizer and rudder were consumed. Flap position could not be determined.
The engine (Rotax 912ULS, SN 6783279) showed extreme heat damage. All four cylinders were attached; no uncontained failure was evident. One propeller blade remained on the hub. Throttle and mixture cables were attached. Spark plugs showed light gray coloring; valve train was movable. The crankshaft could not be rotated by hand.
Medical and Pathological Information
Autopsy of the pilot on February 11, 2016, listed cause of death as blunt force injuries. FAA toxicology tests for carbon monoxide, cyanide, ethanol, and listed drugs were negative.
Additional Information
Some witnesses reported a yellow single-engine airplane in the area; the pilot of a yellow Howard DGA15 stated he overflew the accident site after the crash and did not witness it.
The Airplane Flying Handbook notes that accelerated stalls occur at higher indicated airspeeds due to maneuvering loads, and may lead to loss of control if recovery is not immediate.