Introduction
On November 21, 2015, at 07:15 local time (12:15 UTC), a Cessna A188B agricultural aircraft, registration HK1820, operated by Aplicaciones Aero-agrícolas Ltda. – AVIAL LTDA., experienced a serious incident during an aerial spraying flight. The aircraft was forced to land in an unprepared field near Paratebueno, Cundinamarca, Colombia. The sole pilot on board was uninjured, but the aircraft sustained substantial damage.
Flight Sequence
The aircraft was scheduled to perform aerial spraying on lots in the jurisdiction of Cumaral, Meta. It took off from the "El Vaticano" spraying strip (designation 9DK) in Paratebueno after a successful pre-flight inspection and loading of approximately 160 gallons of agricultural product. Engine start and takeoff roll were normal. During the initial climb, the aircraft experienced a reduction in aerodynamic performance. The pilot jettisoned the chemical load in an attempt to regain flight performance, but the aircraft lost lift and descended into a palm plantation. The impact point was approximately 500 meters from the runway threshold at coordinates N04°17'51.7" W073°11'54.5", with a final heading of 165°. The aircraft came to rest after striking vegetation, suffering damage to its structure, wings, engine, propeller, and landing gear. No post-impact fire occurred.
Aircraft and Engine Information
The Cessna A188B (serial C-18802528T, year of manufacture 1971) had a total of 5,883:15 flight hours. Its Continental IO-520-D engine (serial 174579-R) had 3,628:05 hours total time and 923:00 hours since last major overhaul. The McCauley D2A34C98-0 propeller had 3,644:00 hours. The aircraft's last maintenance service was on November 7, 2015, and it was in compliance with manufacturer's maintenance instructions, maintaining its airworthiness status.
Pilot Information
The pilot, aged 26, held a PCA (Commercial Pilot) license and a valid medical certificate. He had a total of 648:37 flight hours, with 389:05 hours on the Cessna A188B. His last check ride on the aircraft type was on May 9, 2015. No medical, physiological, or psychological factors were found to have influenced the incident.
Investigation Findings
The investigation focused on the engine's partial power loss. The Continental IO-520-D engine was removed and sent to an authorized repair station for inspection. Visual inspection revealed no external discrepancies. The crankshaft rotated freely, and crankshaft flange runout measured 0.0035 inches, within limits. However, examination of the fuel control unit found internal scratches (rayaduras internas) that caused abnormal fuel flow at high power settings. This condition was determined to be the cause of the partial power loss during takeoff.
Damage Assessment
The aircraft sustained substantial structural damage: deformation and fracture of the right wing, dents on the left wing leading edge, propeller blade deformation, dents on the lower engine cowling, and fracture of both landing gear legs. No other damage occurred. The pilot evacuated the cockpit unaided.
Meteorological and Other Factors
Meteorological conditions were suitable for the flight and were not a factor. Navigation aids were not required as the flight was conducted under VFR. Communications were not involved. The incident did not occur at the departure airstrip.
Survival Aspects
The aircraft maintained structural integrity due to the low-speed, low-angle impact. The landing gear absorbed much of the impact forces. The pilot, restrained by seat belts, was uninjured and left the cockpit unaided.
Conclusion
The serious incident resulted from a partial loss of engine power due to a malfunctioning fuel control unit with internal scratches, which disrupted fuel flow at high power settings.