Accident Overview
At 09:18 UTC on 8 December 2016, a private Robinson R44 helicopter (serial 13827) was initiating a cross-country flight from the pilot's property in Roosdaal, Belgium. The helicopter had a single occupant—the pilot—and was loaded with three burlap sacks of walnuts, each weighing about 20 kg. The pilot secured one sack on the left front seat and the other two on the rear seats using the helicopter's safety belts.
Flight History
Immediately after lift-off, while hovering, the helicopter experienced a rocking motion. This caused the front-seat sack to shift and press against the vertical bar of the cyclic control, blocking it entirely. The pilot lost control of the helicopter, which struck the ground with its right skid and rolled onto its right side. The pilot was not injured and exited the aircraft with assistance from a neighbor who had heard the impact.
Aircraft and Safety Restraints
The Robinson R44 (model R44-Raven II, built 2015) was equipped with three-point retractable seat belts featuring a locking mechanism activated by a centrifugal clutch. The report notes that while these belts are effective for securing occupants, they are not designed to restrain cargo. The bags could slide under the belts if the jerking force on the belt spool was insufficient to trigger the lock.
Probable Cause
The investigation determined that the accident was caused by a loss of control at low altitude due to a heavy bag that was not adequately secured, which fell onto the cyclic column and impeded its movement.
Safety Message
The report emphasizes that safety restraint systems with freedom of extension and movement should not be used to secure cargo, especially when cargo could interfere with flight and engine controls. For regular cargo transport, contacting the aircraft manufacturer for guidance is recommended.