What happened
On 10 October 2001, at approximately 11:50Z, a Eurocopter EC 120B, registration ZS-RME, was involved in an incident at the Hera Sub Station. The aircraft was undergoing hot refueling operations when the main rotor blades made contact with the roll bar of a light delivery vehicle. The vehicle and its attached fuel trailer were positioned parallel to the helicopter, within the radius of the main rotor's turning circle.
The investigation
Investigators examined the circumstances surrounding the impact, noting that the helicopter was parked facing an easterly direction. The pilot reported that all control locks were properly engaged at the time of the incident. The investigation focused on the environmental conditions and the positioning of ground equipment during the refueling process.
Findings
Technical analysis established that a sudden gust of wind originating from the six o’clock position caused the rotor disk to tilt and the blades to droop. This movement resulted in the blades striking the roll bar of the parked light delivery vehicle. The presence of the vehicle within the rotor'disk's sweep area during refueling was a significant factor in the contact.