Flight History
On April 11, 2018, at 06:20 local time (11:20 UTC), a Bell 206 L3 helicopter, registration HK4776, operated by Helifly Colombia SAS, departed from Guillermo León Valencia Airport in Popayán, Cauca. The flight was a non-regular passenger transport mission carrying one passenger and internal cargo to Cerro El Pinche, a location in the village of El Plateado, municipality of Argelia, Cauca. The helicopter landed at the designated "safe landing site" at Cerro El Pinche at 07:02 local time (12:02 UTC), 42 minutes after takeoff. After landing, the sole passenger, seated in the left cockpit seat, disembarked and began unloading cargo from the rear of the helicopter.
In-Flight Vibration and Pilot Actions
While the passenger was unloading cargo, the pilot perceived unusual and infrequent flight characteristics: a general oscillation and strong vibration in the helicopter's structure that impaired controllability. In response, the pilot closed the throttle twist grip. The strong vibration caused significant structural damage.
Damage to the Helicopter
The main rotor separated at the swashplate level and detached from the airframe, coming to rest approximately 100 meters from the fuselage. The tail boom twisted at its root. The engine remained in place. Cabin windows separated from the structure, and the instrument panel was displaced from its normal position. The landing gear was intact and slightly embedded in the ground. Doors were misaligned; the right rear door was hanging and broken from the impact of the vibration. Hydraulic and oil lines were ruptured. There was no rollover.
Injuries and Evacuation
Neither the pilot nor the passenger sustained injuries. After the vibration, the pilot shut down the fuel pump and evacuated the aircraft unaided.
Investigation
The accident occurred in daylight under visual meteorological conditions. No post-crash fire occurred. The Grupo de Investigación de Accidentes de la Aeronáutica Civil (GRIAA) arrived at the site on April 12, 2018, to conduct an inspection. The investigation followed international and national guidelines (ICAO Annex 13, RAC 114). Colombia notified the Transportation Safety Board of Canada (as state of manufacture) and the National Transportation Safety Board of the United States (as state of design and engine manufacturer). Accredited representatives from Bell Helicopter and Rolls-Royce assisted in the initial phase of the investigation. No further information on the cause was provided in the report.