Accident Overview
On October 23, 2011, about 1200 central daylight time, a Beech C23, registration N89MH, operated by Columbia Aircraft, Inc., experienced a forced landing shortly after takeoff from Columbia-Marion County Airport (0R0) in Columbia, Mississippi. The pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight under 14 CFR Part 91.
Pilot Actions
The pilot reported that earlier that day he departed from 0R0, flew south about 15 miles, returned, and performed three uneventful touch-and-go landings. After the last touch-and-go, he stayed in the traffic pattern and performed a full-stop landing, then taxied to the ramp, secured the airplane, and took a brief break. He restarted the engine for another local flight.
During the pre-takeoff engine run-up, the pilot noted full rpm. He applied takeoff power, rotated at about 60 mph, and accelerated to 80 mph. When the airplane was approximately 200 feet above ground level, the engine lost partial power and ran “very rough” but continued to operate. The pilot aborted the takeoff, reduced power to idle, and landed on the runway but could not stop before traveling off the end. While in the grass beyond the departure end, the right wing struck an approach aid light, breaching the right main fuel tank. The airplane veered right, went down an embankment, turned 180 degrees, and came to rest upright with the engine idling. The pilot secured the engine and exited. A postcrash fire damaged the aft fuselage, aft cabin, and interior.
Postaccident Examination
A Federal Aviation Administration (FAA) airworthiness inspector inspected the engine and found crankshaft, camshaft, and valve train continuity. Hand rotation of the crankshaft showed suction and compression in each cylinder. All cockpit engine controls were attached at their respective points; however, the mixture control lever at the carburetor was between approximately 1/8 and 1/16 inch from the full rich position while in the cockpit it was set to full rich. The carburetor heat control checked satisfactorily, and the right wing fuel supply system from tank to carburetor was unobstructed. The left wing fuel vent was clear. During hand rotation, the left magneto (with impulse coupling) sparked at all ignition leads, but the right magneto did not produce spark.
Recovery examination by an independent airframe and powerplant mechanic with inspection authorization revealed the left magneto was timed 28 degrees before top dead center (BTDC) and the right magneto 26 degrees BTDC (specification: 25 to 27 degrees BTDC). Very weak spark was noted from the right magneto during hand rotation of the propeller; the magneto was retained for further testing.
Right Magneto Testing
The right magneto was examined and bench tested at an FAA-certified repair station with National Transportation Safety Board oversight. On a test bench with a slave ignition harness, it produced spark consistently at all towers from 150 to 4,704 magneto rpm. Internal timing was set to specification. Disassembly revealed normal carbon dust on the coil tab, normal carbon brush wear, and a normal distributor gear electrode; no carbon tracking was observed. The point gap measured 0.010 inch (specification 0.008 to 0.010 inch), points were not pitted, and cam lobe wear was absent. Coil primary and secondary resistance measured 0.6 and 16,000 Ohms (specification: 0.50 to 1.2 and 13,000 to 20,500 Ohms). The condenser measured 0.361 microfarads (specification: 0.35 MFD plus or minus 10 percent).
Maintenance and Weather
Maintenance records indicated the engine was overhauled in July 2001 and installed on September 26, 2001, accumulating about 431 hours since overhaul at the time of the accident.
A weather observation from Hattiesburg Bobby L Chain Municipal Airport (HBG), about 29 nautical miles from the accident airport, at 1153 (about 7 minutes before the accident) showed temperature 70°F and dew point 45°F. The FAA Special Airworthiness Information Bulletin CE-09-35 notes that these conditions were favorable for serious carburetor ice at glide power settings, with rough engine operation as a symptom.
Probable Cause
None stated.