History of Flight
On August 23, 2010, at approximately 1030 mountain daylight time, a Cessna 310C, registration N896H, was substantially damaged when it struck terrain four miles southeast of Calhan, Colorado. Visual meteorological conditions prevailed, and the instructional flight was conducted under 14 CFR Part 91 without a flight plan. Both the commercial pilot and certified flight instructor (CFI) sustained fatal injuries. The flight departed Meadow Lake Airport (KFLY), Colorado Springs, Colorado, at about 1000. Friends and family reported the purpose was a flight review for the commercial pilot. According to the FAA, the airplane was maneuvering in a practice area and receiving radar flight following from Colorado Springs Approach. Radar data showed the airplane's track began at 1000 east of KFLY at 8,300 feet msl, then maneuvered south and east, climbing to 10,000 feet. The track was lost at 7,200 feet msl at 1029, and the wreckage was located shortly after 1100 by a local resident directly below the last radar hit.
Personnel Information
The commercial pilot, 76, held a commercial certificate with single-engine, multiengine, and instrument ratings, and a special issuance third-class medical dated January 13, 2010, valid until January 31, 2012. He reported 3,425 total hours, with 10 in the preceding six months. The CFI, 60, held an airline transport pilot certificate with multiengine rating, commercial with single-engine and rotorcraft, and a flight instructor certificate. He held a first-class medical with no limitations, and reported 3,850 total hours, 140 in the previous six months.
Aircraft Information
The 1959 Cessna 310C (serial number 35996) had a standard airworthiness certificate for normal operations. It was powered by two Teledyne Continental Motors IO-470-D engines, each rated at 260 horsepower, with two-blade Hartzell propellers. The aircraft was maintained under an annual inspection program; the last inspection was completed on August 3, 2009, at 4,370.7 airframe hours. Since then, it had flown 4.8 hours, bringing the total to 4,375.5 hours.
Meteorological Information
The closest weather reporting station was Colorado Springs Municipal Airport (KCOS), 25 nautical miles southwest of the accident. A METAR at 0954 reported wind from 060 degrees at 17 knots, visibility 10 miles, scattered clouds at 11,000 feet, temperature 26°C, dewpoint 11°C, and altimeter 30.24 inches of mercury.
Wreckage and Impact Information
The aircraft came to rest upright in an open field with rolling terrain, oriented on a measured heading of 358 degrees at an elevation of 6,878 feet msl. The fuselage nose was unremarkable, but the nose landing gear was pushed upward, and the forward cabin area was crushed in an accordion manner. The windscreen was fragmented, the instrument panel dislodged, and the aft fuselage and empennage showed upward accordion crushing. Observed instrument readings included an altimeter set to 7,000 feet (Kollsman window 30.23), a vertical speed indicator indicating 980 feet per minute descent, and a heading gyro at 118 degrees. Both fuel selectors were on the main tanks, the auxiliary fuel pump left switch was on, and the right switch was broken. The left side of the empennage and fuselage was torn. The forward vertical stabilizer separated, canting the empennage right. The upper rudder counterweight separated and was found 55 feet south. A dark blue paint transfer mark was on the right rudder. Control continuity was established to the rudder and elevator. Both wings remained attached; tip tanks were split open, and the left fuel bladder was torn. The left aileron control cable separated due to overload. The right main landing gear was extended and deflated. The right propeller had one blade separated and embedded in the ground with spanwise scoring and an S-bend; the left propeller was horizontal with chordwise scratches and polishing on one blade. The right engine crankcase was cracked, and the fuel pump and magnetos separated. Oil was present.
Medical and Pathological Information
Autopsies of both pilots, performed by the El Paso County Coroner's Office on August 24, 2010, attributed the cause of death to multiple blunt force injuries. Toxicological tests by the FAA's Civil Aerospace Medical Institute found negative results for carbon monoxide, cyanide, and volatiles in the commercial pilot, and candesartan in urine. The CFI tested negative for carbon monoxide, cyanide, and drugs; ethanol (67 mg/dL in muscle) and methanol (1 mg/dL in muscle and brain) were detected but attributed to postmortem formation.
Tests and Research
The wreckage was moved to Greeley, Colorado, where both engines were examined. Rotation by hand showed valve movement and air movement in all cylinders. Engine-driven fuel pumps rotated freely with continuous splines, and magnetos produced a blue spark. Normal operating signatures were noted. Fuel boost pumps showed no anomalies.
Probable Cause
No probable cause was stated in the provided source.