History of the Flight
On 3 August 2011 at approximately 0630Z, a Robinson R44 Raven II helicopter, registration ZS-HTY, departed from Cape Town International Airport on a private flight with a pilot and three passengers. The purpose was aerial photography of the University of Cape Town campus. After taking off, the helicopter flew towards Kenilworth racecourse and then to Rhodes Memorial, with a photographer in the right-hand aft seat (the right-hand aft door had been removed).
Approaching the lower campus from a north-easterly direction at a speed of 50-60 knots and approximately 800 feet above mean sea level, the helicopter suddenly began an uncontrolled descent. The pilot attempted to increase forward speed and height but could not arrest the descent. He then opted to perform a forced landing.
At about 200 feet above ground level, the right-hand skid gear contacted a large tree that the pilot could not avoid. Subsequently, the helicopter impacted the ground and a perimeter fence, rolling onto its left side.
A passenger (the photographer) later reported that during the flight, the pilot had difficulties controlling the helicopter in a hover, feeling it move forward and descend. After several repositioning attempts, the helicopter entered what felt like a free fall. The pilot made a last-minute attitude change by raising the nose before impact.
Injuries to Persons
The pilot sustained minor head injuries. None of the three passengers were injured.
Damage to Aircraft
The helicopter sustained substantial damage. The left-hand landing skid collapsed during the impact sequence, and the helicopter rolled onto its left side. Minor damage occurred to surrounding vegetation, a perimeter fence, and a road sign.
Personnel Information
The pilot, aged 58, held a valid Private Pilot (Helicopter) license with no restrictions or previous accidents. Total flying experience was 173.2 hours, including 25.8 hours on the Robinson R44. He had flown 4.0 hours in the past 90 days, with 1.0 hour on type.
Aircraft Information
The helicopter was a 2008 Robinson R44 Raven II (serial number 12458) with a total airframe time of 532.9 hours at the time of the accident. The last maintenance (MPI) was completed on 31 May 2011 at 491.1 hours. The engine was a Lycoming IO-540-AE1A5 with 532.9 hours since new. The helicopter was operated under Standard Part 127.
Weight and balance calculations showed the take-off weight exceeded the maximum gross weight of 2500 lbs by 57.94 lbs. After approximately 30 minutes of flight, fuel burn-off reduced the weight to about 2502.94 lbs, still exceeding the limit.
The right-hand rear door had been removed; no documentation indicated it was removed by a qualified person as per the maintenance manual. Flight with the door removed is permitted up to 100 KIAS per the Pilot's Operating Handbook.
Meteorological Information
Wind was north-westerly at 20 knots, temperature 14°C, visibility greater than 10 km, with no clouds.
Wreckage and Impact Information
The accident site was on Cross Campus Road, Cape Town (GPS: S 33°57'19" E 018°27'53"). The final flight path was in a direction of approximately 200° magnetic. The helicopter first struck high trees to the northern side of the scene before impacting the ground. A passenger reported the helicopter was in a level attitude during initial tree contact.
Probable Cause
The investigation determined the probable cause was a vortex ring state (settling with power) rendering ground impact inevitable. A contributing factor was the pilot's lack of experience on the helicopter type.