Accident Details
On 7 May 2003 at approximately 1040Z, a Eurocopter AS 350-B3 helicopter, registration ZS-RPD, was engaged in a crime prevention operation in the lower Drakensberg area. The pilot, accompanied by a crew member and three passengers (policemen), was orbiting a kraal in Wonder Valley at a speed of about 50 knots and a height of 50–100 feet AGL when a suspected marijuana field was observed. A person was seen running from the field with two bags.
To keep the suspect in sight, the pilot executed a right turn. After one orbit to the right, the pilot felt the aircraft descending. He rolled the helicopter level, facing down a ridge, and increased collective pitch into the yellow arc on the First Limit Indicator (FLI). Despite this, the aircraft continued to descend. The pilot further increased collective pitch, but the helicopter impacted the ground in a level attitude on both skids in a maize field. During forward motion, the left skid dug into the ground, causing the aircraft to roll forward and to the left, coming to rest on its left side in a ditch.
The engine remained running; the pilot shut it down by closing the fuel shut-off lever. The three passengers disembarked on the left side. After switching off all electrical switches, the pilot and crew member also exited on the left side into the ditch.
Injuries and Damage
Four people were injured. No fatalities were reported. The aircraft sustained substantial damage due to the impact and rollover.
Probable Cause
The official investigation stated the probable cause as follows: During an attempt by the pilot to keep a suspect visual, he executed a right turn followed by a deceleration of the aircraft with the intention to execute a landing to arrest the suspect. Due to diverted attention during the subsequent manoeuvre, the pilot most probably allowed the main rotor RPM to decay to as low as 320 rpm (information obtained from DECU download). The pilot noted the high rate of descent once he levelled the aircraft and attempted to recover by applying collective pitch, but due to insufficient height available, the aircraft continued to descend at a substantial rate until it impacted with terrain in a level attitude, followed by a subsequent roll-over.