History of Flight
On 21 October 2008 at 1030Z, an instructor and a licensed student pilot departed from Grand Central Aerodrome (FAGC) in a Robinson R22 Beta II helicopter, registration ZS-RMJ, for a training flight. The purpose was to conduct autorotation and flaring exercises in the general flying area south of Allandale Road. The helicopter had been refueled to full capacity prior to departure. Using Runway 35, the student pilot climbed to an altitude of 6000 feet above ground level (AGL).
Both pilots initiated an autorotation exercise over an open area outside the aerodrome boundary. The student pilot descended to approximately 6 feet AGL to perform a flare. During this low-level maneuver, the tail rotor struck an ant hill on the ground. The student lost tail rotor effectiveness, causing the helicopter to yaw left and impact the ground heavily on its skid.
Damage
The impact caused the tail rotor, empennage, and tail rotor gearbox to separate from the tail boom. The skids, main rotor blades, and tail boom sustained substantial damage. The helicopter's right skid collapsed, and the tail section detached. No fire occurred, and the cockpit remained intact.
Injuries and Occupants
One instructor and one student pilot were on board. Neither sustained any injuries.
Aircraft Information
The Robinson R22 Beta II (serial number 3131, year of manufacture 2000) was owned and operated by Helicopter Training Services. It had a total airframe time of 3707.6 hours at the time of the accident. The last Mandatory Periodic Inspection (MPI) was performed on 16 October 2008 at 3699.0 hours, and the helicopter had flown 8.6 hours since. Weight and balance were within limits, with a total take-off weight of 1304.78 lbs (well below the maximum of 1371.27 lbs).
The engine was a Textron Lycoming O-360-J2A with 3652.7 hours since new and 49.9 hours since overhaul.
Meteorological Conditions
At the time of the accident, visibility was good with no clouds. Temperature was 25°C, wind direction 180° at 3 to 9 knots. No significant weather was reported.
Location
The accident occurred in an open area adjacent to Grand Central Aerodrome, at GPS coordinates S25°59.380' E28°08.035', elevation 5325 feet.
Personnel
The instructor held a valid Commercial Pilot Licence, a Grade 2 Helicopter Instructor Rating, and an Instrument Rating. He was 35 years old with 1102.8 total flying hours, including 358.9 hours on type. The student pilot was a licensed pilot undergoing training.
Probable Cause
The South African Civil Aviation Authority determined that the probable cause of the accident was that the tail rotor impacted an ant hill during a low-level flight. A contributory cause was the failure of the instructor and the student to look out for obstacles.