What happened
On August 23, 2014, an EC-130B4 helicopter, registration PR-NEO, was performing a local transfer flight in Goianira, Brazil. The flight originated from an unregistered and uncertified location to a soccer field in the same municipality.
During the approach, the pilot reported a sudden, inadvertent yawing tendency to the left while reducing speed. Following this movement, the pilot decided to proceed immediately with a landing at the soccer field. As the aircraft was positioning itself to park, the main rotor blades struck the top of a soccer goal. The impact caused substantial damage to the rotor blades and resulted in perforations to the tail cone and vertical stabilizer. Metal fragments from the goalpost were propelled 43 meters away, damaging a nearby residential gate. The pilot and the passenger were unharmed.
The investigation
CENIPA investigators examined the aircraft's engine and flight command systems, utilizing data from the Vehicle and Engine Multifunction Display (VEMD). The investigation confirmed that there were no engine failures or abnormal mechanical parameters recorded.
Investigators also analyzed video footage captured by a bystander, which showed the aircraft completing its descent approximately 3 meters from the ground. The investigation compared the aircraft's position to the obstacle, finding that the distance from the rotor mast to the goal was 5.23 meters, while the rotor blade tip radius was 5.35 meters. Furthermore, the height of the goal (2.55m) exceeded the measured height of the rotor blade tip from the ground (2.47m) during the static measurement.
Findings
- Inadequate obstacle clearance: The landing was performed at an uncertified location without maintaining sufficient lateral or vertical separation from obstacles.
- Erroneous judgment: The pilot made an incorrect assessment of the distance between the aircraft and the goalpost during the landing phase.
- Environmental factors: A left wind component with gusts likely contributed to the sudden yawing movement observed during the transition from cruise to low speed.
- Lack of awareness: The pilot was not aware of the specific flight characteristics and precautions outlined in Service-Letter 1673-67-04 regarding yaw control in this aircraft type.