Flight History
On 30 April 2019, a Bell 206 L3 helicopter, registration HK3312, was scheduled for an external load flight to support an electrical interconnection project in Sabanalarga, Antioquia. The helicopter was initially at a Colombian Army battalion in Ituango and flew to the Valle de Toledo collection point in Toledo, Antioquia, located 9.15 NM to the southeast, to pick up cargo. After landing normally, a long line was attached to a load of cable guide pulleys weighing 804 lb. The helicopter then departed for the Sabanalarga collection point, 10 NM to the southwest, to assist in installing electrical lines on towers TM058 and TM059.
At approximately 10:20 local time, during the final approach to the Sabanalarga point, light orographic turbulence with wind variations was encountered. The pilot faced the helicopter into the wind in a hover at an altitude between 100 and 150 feet. The helicopter subsequently experienced a loss of altitude with a high rate of descent. The pilot applied power in an attempt to recover altitude but was unsuccessful. He decided not to release the load to prevent it from falling on ground personnel. Once the load contacted the ground, the pilot moved the helicopter forward to gain translational lift, but the helicopter struck the terrain hard and rolled over dynamically to the left.
Injuries and Damage
The sole occupant, the pilot, was uninjured and evacuated the helicopter without assistance. No injuries occurred on the ground. The helicopter sustained significant structural damage: the tail boom separated, and the main rotor blades and fuselage were heavily damaged. A small engine fire started after the accident but was extinguished by the pilot and ground personnel using an onboard fire extinguisher.
Investigating Authority
The Colombian Accident Investigation Group (GRIAA) was notified at 10:40 local time and dispatched an investigator from Bogotá. Notifications were sent to ICAO and to the design and manufacturing state authorities: the Transportation Safety Board of Canada and the National Transportation Safety Board of the United States, who appointed accredited representatives and technical advisors.
Probable Cause and Contributing Factors
The investigation determined the probable cause of the accident was a hard landing resulting from a sudden and inadvertent loss of altitude during the approach, caused by the helicopter entering an aerodynamic condition of settling with power. Contributing to the accident were fluctuating wind conditions in the surrounding area, related to orographic and thermal turbulence.