Aircraft and Flight Details
The aircraft involved was a Piper PA-23, registration HK912, manufactured in 1966 and operated by Aviones Publicitarios de Colombia S.A.S. At the time of the accident, the aircraft was configured as a twin-engine, propeller-driven airplane. The flight was a special air service mission for aerophotography along the Sogamoso River area in the eastern cordillera foothills, monitoring electrical lines.
Accident Sequence
On June 29, 2015, the aircraft departed from Yariguies Aerodrome (SKEJ) at 10:20 local time (15:20 UTC) for the photography mission. The flight proceeded normally. At 12:43 local time, the crew contacted SKEJ control tower and requested landing clearance. They were initially cleared for runway 04, but the pilot requested runway 22, which was granted. At 12:46, the tower lost visual contact with the aircraft during the final approach. A Piper-28 aircraft in the vicinity confirmed the HK912's location near the runway 22 threshold. The accident occurred at 12:47 local time under visual meteorological conditions (VMC). The tower then alerted the airport fire and rescue services, who assisted the occupants.
Injuries and Damage
All three occupants—the pilot, copilot, and technical operator—were uninjured and evacuated the aircraft unassisted. No post-impact fire occurred. The aircraft sustained substantial structural damage, including fuselage deformation, detachment and deformation of both wings, damage to the vertical stabilizer, sudden stoppage of both engines, propeller blade deformation, and landing gear fracture. Additionally, three sections of the airport perimeter fencing were damaged by the left wing.
Investigation Findings
The investigation determined that during the final approach, the right engine-propeller group exhibited abnormal operation. Examination of maintenance records and physical evidence revealed that the right propeller governor rack had been incorrectly installed during a 100-hour inspection performed on March 20, 2015, at an authorized Repair Station (TAR). The rack's misinstallation prevented proper propeller pitch control. The investigation also found deficiencies in the assembly procedures prescribed by the manufacturer, as well as failures in supervision and non-standard maintenance practices by the Repair Station.
Probable Cause
The accident resulted from the incorrect installation of the right propeller governor rack, shortcomings in following the manufacturer's assembly procedures, and failures in supervision and non-standard maintenance practices by the Repair Station.