Incident Overview
On 29 December 2021, a Cessna A188B aircraft, registration HK-2014, operated under special aerial work for agricultural spraying, was conducting operations over a rice field near Yopal, Casanare, Colombia. The aircraft had completed one flight (three spray passes covering 30 hectares) without any reported malfunctions. During the second flight, approximately 15 minutes after takeoff, the engine experienced a sudden explosion accompanied by strong vibration, white smoke, and a complete loss of power.
Emergency Landing
The pilot identified the engine malfunction and selected an unprepared field for an emergency landing. The aircraft was landed in a controlled manner, as described in the company's operations manual. The aircraft sustained no damage to its structure or landing gear. The pilot, who was the sole occupant, was uninjured and exited the aircraft by his own means. The landing site was at coordinates N 05° 25'1.48" W 072° 12' 57.80", at an elevation of 214 meters, with easy access.
Aircraft and Engine Damage
Preliminary examination revealed substantial damage to the engine, specifically to the crankcase, resulting from an internal explosion during flight. The engine had been installed in the Cessna 188B, a single-engine agricultural aircraft designed for spraying operations.
Investigation Findings
The investigation determined that the total engine failure was caused by the fracture of the connecting rods in positions 4 and 5, likely due to improper installation of the rod bearings. Contributing factors identified included inadequate guidance for maintenance personnel in the specialized workshop's inspection procedures, lack of clarity in the General Maintenance Manual regarding delivery of engines after maintenance, premature aging of the connecting rod material from high temperatures and friction, possible incorrect bearing installation leading to migration and lubrication system blockage, and absence of standard maintenance practices during installation and removal of internal engine components.
Probable Cause
The probable cause of the serious incident was determined as the emergency landing in an unprepared field due to total engine failure, caused by the fracture of the connecting rods in positions 4 and 5, probably due to incorrect installation of the bearings.