History of Flight
The aircraft, a Cessna P210N registered ZS-KIW, had undergone extensive maintenance the week prior, including a mandatory periodic inspection. During a subsequent test flight at FAWB, the engine exhibited a vibration, prompting a decision to have the propeller dynamically balanced by an approved maintenance organization.
On the morning of 15 April 2002, the propeller was balanced at Lanseria. The pilot then took the aircraft for a flight to verify the vibration was resolved. Approximately 8 nautical miles northwest of Lanseria, the pilot observed that fuel flow was very low, though the engine was producing sufficient power. He noted a slight vibration both before and after turning on the low boost pump. Concerned, he decided to return to FALA (Lanseria).
During the return, the engine continued to produce excellent power, but fuel flow remained significantly lower than normal. After turning onto final approach, the aircraft began to sink. The pilot applied additional throttle but received no engine response. He checked the magneto key position, low boost fuel pump, switched fuel tanks, applied rich mixture, and moved the throttle to full, all without result. The pilot transmitted a mayday call, advising that he would be short of the runway. The aircraft crash-landed in a grass field approximately 100 meters short of the airport boundary fence.
Injuries and Damage
The sole occupant, the pilot, was not injured. The aircraft sustained extensive damage to the propeller, wings, and lower fuselage. A fence along the roadside also sustained minor damage. There was no fire.
Tests and Research
After the accident, the aircraft was recovered and prepared for an engine run with the engine still mounted in the airframe. The propeller was replaced and a fuel leak in the fuel bowl (from accident damage) was repaired. During the test run, the engine ran smoothly up to 1800 RPM but then gradually failed regardless of throttle setting, mixture, or boost pump use. Investigation revealed debris in three of six cylinders, which closed the gap between the side and center electrodes on three spark plugs, causing engine failure. After replacing the spark plugs, the engine ran smoothly but still indicated low fuel flow. The fuel nozzles were found clean, but contamination was discovered in the pipe leading to the fuel flow gauge, which had caused a false low indication. Once the blockage was removed, fuel flow returned to normal.
Probable Cause
The probable cause was determined to be an incorrect throttle linkage adjustment (set at 4 lbs at 15 inches of manifold pressure instead of 4 lbs at 23 inches), which caused a rich mixture engine cutoff when the throttle was retarded during landing. Additionally, contamination in the fuel flow gauge line resulted in a false gauge indication.