Incident Overview
On 13 June 2019 at 12:02 LMT, a Guimbal Cabri G2 helicopter operated from Dęblin airport (EPDE) experienced a control system anomaly during a hover taxi to the holding point on the start line. The pilot, holder of a PPL(H) license, noted limited ability to move the right cyclic control from neutral to the left. Simultaneously, the left cyclic control moved forward and left on its own. Despite a slight left bank, the pilot landed the helicopter safely with no further consequences.
Post-Inspection Findings
Following the incident, the operator grounded all Guimbal Cabri G2 helicopters pending investigation. A maintenance mechanic from the maintenance organization inspected the flight control system and found that the nut securing the left control stick had loosened. After performing the required maintenance actions specified by the CAMO, a test flight was conducted with no abnormalities detected. Subsequently, the attachment of the flight control systems on all Cabri G2 helicopters was checked, and they were returned to service.
Probable Cause
The incident was attributed to the loosening of the nut securing the left control stick.
Preventive Actions
The operator implemented preventive measures including inspection of control system attachments on all Cabri G2 helicopters, applying torque seal to the nuts, and conducting training for all aircrew on verifying the security of flight control system attachment bolts during operations.