What happened
On April 12, 2015, two aircraft operating as part of a flight training formation for the Aeroclub de Colombia aviation school collided with the mountains of the Serranía de los Yariguíes, near San Vicente de Chucurí, Colombia. The formation, designated as Squadron No. 2, consisted of a Cessna 172S (registration HK5064G) carrying an instructor and a student pilot, and a Cessna 150M (registration HK1912G) carrying a student pilot.
The flight was planned as a VFR (Visual Flight Rules) operation from Yariguies (SKEJ) to Guaymaral (SKGY). During the flight, the crew reported encountering adverse weather and decided to deviate from their original route to fly via Zapatoca, San Gil, and Socorro. While navigating this new path, the aircraft encountered low cloud cover. The aircraft subsequently impacted the terrain, resulting in three fatalities: two occupants of the Cessna 172S and the single occupant of the Cessna 150M.
The investigation
The GRIAA investigation established that the aircraft entered instrument meteorological conditions (IMC) unintentionally. While the flight was intended to be VFR, the low cloud cover over the mountains limited visibility and prevented the pilots from maintaining visual separation from the terrain.
The investigation also reviewed the flight school's operational specifications, finding that the approved VFR routes did not include the trajectory flown during the accident. Furthermore, investigators noted that the instructor's most recent flight check had been conducted in a static simulator and did not include evaluations of radio navigation or IFR (Instrument Flight Rules) procedures. The aircraft were found to be in compliance with all maintenance requirements, and there was no evidence of structural failure or mid-air collision prior to the impact with the terrain.
Findings
- Unintentional flight in IMC: Both aircraft inadvertently entered low-visibility conditions that prevented visual navigation and terrain clearance.
- Inadequate risk management: The instructor failed to properly assess and manage the risks associated with the existing weather conditions in the planned sector.
- Organizational and regulatory gaps: The flight school's policies regarding instructor flight checks and operational procedures were found to be overly permissive or insufficiently rigorous.