What happened
On September 25, 2021, a Bell 206 L3 helicopter, registration HK3353, was performing a VFR air taxi operation between Guaymaral Airport (SKGY) and Puerto Berrío. After an initial leg, the aircraft stopped in Puerto Berrío to refuel. During this stop, the pilot performed a "hot refuel" with the engine running at minimum RPM. Due to a communication breakdown between the pilot and the ground personnel, only 6 gallons of fuel were added to the tanks, despite the pilot's mistaken belief that 60 gallons had been provided.
During the return flight to Guaymarable, approximately 52 minutes after takeoff, the "FUEL LOW" warning light illuminated, indicating only 10 gallons remained. The pilot, still operating under the false assumption that the aircraft had sufficient fuel, continued the descent toward the destination. As the aircraft passed near Chía, Cundinamarca, the pilot noticed fluctuations in torque and turbine temperature (TOT) readings. Anticipating an engine failure, the pilot initiated an autorotation toward an unprepared field. However, during the final flare, the engine suffered a sudden shutdown due to fuel exhaustion. The resulting hard landing caused the main landing gear struts to collapse and the tail rotor assembly to detach. The pilot sustained a serious spinal injury, while the two passengers were uninjured.
The investigation
The GRIAA investigation focused on the refueling process and the pilot's decision-making following the low-fuel warning. Investigators examined the communication between the crew and the fuel provider, noting that the pilot did not perform a visual fuel check or verify the fuel quantity against the hydrometer reading. Furthermore, the investigation reviewed the pilot's failure to recalculate the weight and balance or interpret the fuel alarms according to standard checklists, which would have prompted an immediate landing at an intermediate point.
Findings
- The primary cause of the accident was a hard landing resulting from a sudden engine shutdown caused by fuel exhaustion.
- Inadequate supervision and verification by the crew during the refueling process, combined with poor communication with the fuel provider, led to an insufficient fuel load.
- The crew exhibited overconfidence by dismissing the low-fuel warnings and failing to act on the fuel level indications.
- A contributing factor was the lack of standardized refueling procedures among ground support personnel, which prevented effective communication with the pilot.