What happened
On 2 July 2012, a Bell 412 helicopter, registration EC-KSJ, operated by Inaer, was engaged in firefighting efforts near Cortes de Pallás, Valencia. The aircraft was performing water-loading operations at the La Forata reservoir, using a suspended tank known as a bambi bucket to collect water for extinguishing nearby flames.
During the ninth water-loading attempt, the helicopter was approaching the reservoir with a non-zero translational speed. As the pilot lowered the bucket into the water, the bucket acted as an anchor, creating massive drag that abruptly arrested the aircraft's forward motion. This sudden deceleration caused the bucket to swing uncontrollably. The swinging tank struck the underside of the helicopter, damaging the engine control linkages and the left horizontal stabilizer. Consequently, the pilot lost control of the aircraft, which impacted the water and sank.
The investigation
The CIAIAC investigation focused on the flight dynamics during the water-loading maneuver and the mechanical damage sustained by the aircraft. Investigators recovered the Digital Flight Data Recorder (DFDR) memory, which provided critical data regarding the aircraft's altitude and speed at the time of the accident. The investigation also examined the pilot's experience, the operator's training procedures, and the mechanical state of the engine controls and stabilizers.
Findings
- The primary cause of the accident was conducting a water loading operation where the bambi bucket was lowered into the water before the helicopter had arrested its translational speed.
- The resulting drag caused the bucket to swing, striking the engine control linkages and causing a loss of power and control.
- The pilot had limited experience with this specific type of firefighting operation, having performed only about 14 hours of such work since obtaining his agricultural rating in 2004.
- The pilot was not wearing a life vest at the time of the crash.
- The electrical release switch for the bambi bucket was not armed, which would have allowed for a quicker emergency release of the load.
- The pilot had not received specific training for emergency water ditching or evacuations in such environments.