History of Flight
On January 29, 2009, about 1450 eastern standard time, a Cirrus Design Corporation SR22, N224SB, was substantially damaged when it impacted terrain while on final approach to Berkley County Airport (MKS), Monks Corner, South Carolina. The certificated commercial pilot/owner was fatally injured. Visual meteorological conditions prevailed, and no flight plan was filed for the flight, which departed Charleston International Airport (CHS), Charleston, South Carolina about 1440 and was destined for Lake Norman Airpark (14A), Mooresville, North Carolina. The personal flight was conducted under 14 Code of Federal Regulations Part 91.
Data from the airplane's Primary Flight Display (PFD) and Multi-Function Display (MFD), along with air traffic control radar and voice communication data, showed that the airplane departed CHS about 1440 and began tracking northwesterly. About 1446, the pilot advised ATC, "I have some fumes in the cockpit, I'm turning around." He then stated he was diverting to MKS and was issued a frequency change. No further communications were received.
The airplane leveled about 5,800 feet above mean sea level, turned toward MKS, and began descending. It passed north of MKS, and about 1448 the MFD data ceased recording. About 1449 the airplane reversed course toward runway 23 at MKS. The last radar position was at 1449:18, at 700 feet msl, about 2 nautical miles northeast of the runway 23 threshold. The PFD ceased recording position information around this time, but other parameters recorded until 14:50:15. The final recorded data included 148 feet pressure altitude, 93 knots indicated airspeed, 232-degree heading, and a positive pitch of 0.6 degrees.
Witness Observations
Several witnesses observed the airplane on final approach to runway 23. Three were certificated pilots who recounted similar events. They stated the approach initially looked normal; no flames or smoke were observed. The airplane cleared trees and a fence before the approach end of the runway, then pitched over and went down. The attitude was consistent with a normal approach until it unexpectedly pitched down into a near 45-degree dive and impacted terrain. One witness responded immediately and noted no fire, smoke, or abnormal fumes.
Aircraft Information
The pilot held a commercial pilot certificate with single-engine land and instrument ratings, and 1,164 total flight hours. His most recent second-class medical was issued June 5, 2008.
Maintenance records showed the airplane's most recent annual inspection was completed November 13, 2008, at 903 total hours. On January 7, 2009, the pilot had avionics service performed after reporting an odor of burnt electronics in the cockpit during a previous flight. The repair station inspected components and wiring, cleaned connections, and reflowed solder joints. No trouble was found with any systems, and no unusual odors were detected during extended ground runs.
Meteorological and Airport Information
Weather reported at MKS at 1455 included clear skies, 10 statute miles visibility, winds from 340 degrees at 3 knots, temperature 12°C, dewpoint 7°C, and altimeter 29.95 inHg.
Berkley County Airport has a single 4,351-foot-long by 75-foot-wide asphalt runway oriented 05/23. A two-light precision approach path indicator on the left side of runway 23 projected a 3-degree glide path. The airport is bounded by a perimeter fence, with the northeastern boundary about 1,070 feet from the approach end. Terrain between the fence and runway 23 threshold is flat with no obstructions.
Wreckage and Impact
The initial impact point was an imprint consistent with the wings and landing gear, located about 875 feet from the runway 23 threshold. The nose landing gear was at the center. The wreckage path oriented about 210 degrees magnetic, with composite structure debris. The propeller was about 35 feet from the impact point; the main wreckage came to rest about 120 feet beyond, oriented about 138 degrees magnetic.
The fuselage was destroyed forward of the forward seats, but the aft portion remained intact. No evidence of in-flight or post-impact fire was observed. The integrated airframe parachute system was intact and not deployed. The right wing separated at the aft wing root; the left wing remained attached. Control continuity was traced to the cabin. The flap actuator measured at 50% flap position.
Battery master switches and alternator switches were in the "on" position. The avionics switch was "off". Ice protection, pitot heat, and exterior light switches were "off". The fuel selector was on the right tank, and the electric fuel boost pump switch was neutral. The magneto switch was in the "both" position with the key broken off. All circuit breakers were in their operative positions except "fuel pump," "turn cord. #2," and "attitude #2," which were extended and had broken crowns. No evidence of soot, melting, or overheating was noted on the circuit breaker panel or transient voltage suppressors.
Various avionics components were removed for examination. The propeller blades exhibited chordwise scratching, polishing, bending, and one blade had leading edge gouging and a missing tip portion.
Engine Examination
The engine was examined at the scene and during a teardown inspection. It remained largely intact with impact damage. The crankshaft rotated by hand, and compression was noted on all cylinders. Continuity was present from the propeller flange to rear accessory gears, ignition, and fuel system. Rotation produced spark at magneto leads. The cabin heater shroud showed no staining or leakage. The crankshaft propeller flange had separated, with cracks consistent with torsional loads. No abnormalities were found in the engine or its components.
Medical and Pathological Information
An autopsy on the pilot noted the cause of death as "blunt trauma." Toxicological testing detected no carbon monoxide, cyanide, or ethanol. Quinine was detected in the blood.
Tests and Research
Examination of the autopilot control head, roll trim motor, MFD, radios, audio panel, transponder, turn coordinator, enhanced ground proximity warning system, and master control unit revealed no evidence of failures, fire, or thermal distress. The autopilot control head and roll trim motor passed acceptance tests.
The PFD was disassembled and examined. A single tantalum capacitor in the +/-15 volt switching power supply circuit was thermally damaged. The capacitor was in parallel with an identical capacitor to reduce switching noise. The output powered analog and digital signals to the autopilot and ARINC 429 data bus. The circuit board with the damaged capacitor was partially tested and installed into a known working PFD; both tests suggested normal operation, with no anomalies noted.