What happened
The aircraft was engaged in an aerial application mission when it experienced a sudden loss of engine power immediately following takeoff. The pilot reported that this event occurred during the fifth flight of the day. After departing from runway 27, the aircraft climbed to approximately 125 feet above ground level (AGL) before the engine performance began to degrade.
Recognizing the mechanical failure, the pilot reduced power and executed a forced landing straight ahead. The landing site was located approximately 50 yards beyond the end of the takeoff runway. During the impact of the forced landing, the aircraft's landing gear collapsed, causing significant structural damage to the undercarriage.
The investigation
Following the accident, investigators examined the engine to determine the root cause of the power loss. The inspection revealed that the lower spark plugs contained a dark grey deposit that had bridged the electrodes. This deposit weakened the electrical spark generated by the plugs, leading to inefficient combustion and subsequent power failure.
When the deposits were cleared from the plugs, they produced a stronger spark, confirming that the fouling was the primary mechanical issue. The spark plug fouling directly contributed to the engine's inability to maintain power during the critical climb phase after takeoff.
Findings
The investigation determined that the loss of engine power was caused by fouled lower spark plugs. The deposit bridging the electrodes prevented proper ignition, leading to a misfire and subsequent power reduction. The pilot's decision to land straight ahead minimized further damage, although the landing gear failure resulted in additional aircraft damage.