What happened
On February 14, 2025, a Bell 206 L3 helicopter, registration HK5189, was performing a specialized external cargo mission near El Copey, Cesar, Colombia. The aircraft was transporting a water tank suspended by a 6-meter sling.
During the approach to the load release point, approximately three minutes after takeoff, the pilot experienced a sudden loss of altitude. The external load became entangled with local vegetation and a barbed-wire fence. Although the pilot attempted to release the load electronically, the mechanism failed to decouple the weight. The aircraft continued to descend, impacting the terrain and vegetation, which caused the main rotor mast to sever. The helicopter entered an uncontrolled spin and ended up inverted. A post-impact fire, fueled by the interaction between spilled fuel and dry vegetation, consumed much of the aircraft. The pilot successfully evacuated the wreckage without injuries.
The investigation
The GRIAA investigation examined several critical factors, including meteorological conditions, aircraft performance, and the technical configuration of the cargo hook system. Investigators analyzed satellite imagery and regional weather data, noting that the accident occurred during a period of high daytime temperatures and thermal turbulence.
Technical analysis of the cargo hook revealed that the primary attachment point was made directly to the metal structure of the tank rather than using a certified aeronautical rigging method. Furthermore, the investigation identified a lack of reliable weight verification, as there was no evidence of valid calibration for the scales used to weigh the external load. The investigation also noted inconsistencies between the documentation for the cargo hook system and the manufacturer's technical warnings regarding attachment rings.
Findings
- The primary cause was the loss of control during a pinnacle-type approach under power-limited conditions, resulting from a combination of high density altitude, gusty winds, and the transport of an uncertified liquid load.
- The actual weight of the external load was not validated prior to flight.
- The external load became trapped due to the failure to follow manufacturer recommendations regarding the cargo hook attachment.
- The pilot failed to execute an immediate load release when the initial descent was detected, choosing instead to continue the maneuver.
- The use of a liquid load without proper anti-sloshing measures (such as baffles or partial filling) contributed to dynamic center-of-gravity shifts.
- Operational deficiencies included inadequate risk assessment for confined area operations and a lack of documented weight and balance verification.