Robinson R44 II Accident at Mossel Bay Aerodrome (ZS-HFW)

Accident Overview and Flight History On 14 April 2009, a Robinson R44 II helicopter, registration ZS-HFW, operated by George Sky Aviation (Pty) Ltd, was involved in an accident at Mossel Bay Aerodrome (FAMO). The aircraft was on a training flight from George Aerodrome (FAGG) to Mossel Bay Aerodrome. The flight was a conversion training exercise for a student pilot, which included procedures for operating with the hydraulic system deactivated. ## Operational Details and Loss of Control The pilot-in-command was a 43-year-old commercial pilot with 245.1 total flying hours and 61.9 hours on type. The student pilot was 55 years old with 142.6 total hours and 1.0 hour on type. During the training, the student pilot was required to deactivate the hydraulic switch. Following this, the student reported that the controls felt stiff. The instructor pilot explained that the hydraulic system needed to remain off for the exercise. The student pilot managed to establish a hover above the threshold of runway 09 at Mossel Bay Aerodrome. After holding a steady hover for a short period, the student began to lose control of the aircraft. The instructor instructed the student to reactivate the hydraulic switch, which is located on the student's side of the cyclic control. The student pilot froze on the controls and did not activate the switch in time, resulting in the helicopter impacting the ground vertically at approximately 20 feet above ground level. ## Aircraft Condition and Meteorological Factors The aircraft was a 2006-manufactured Robinson R44 II with serial number 11340. At the time of the accident, the airframe had 629.8 hours. The engine was a Lycoming IO 540-AE1A5. The helicopter was not fitted with a cockpit voice recorder or flight data recorder, as these were not required for this type of aircraft. Meteorological conditions at the time of the accident were favorable, with a surface wind of 012 degrees at 5 knots and visibility reported as CAVOK. The temperature was 25 degrees Celsius. The helicopter's center of gravity was within limits, and the aircraft was capable of hovering in ground effect up to a pressure altitude of 9,700 feet. ## Investigation Findings and Probable Cause The helicopter was destroyed during the impact, with damage to the airframe, skids, tail boom, and main and tail rotors. There was no evidence of a pre- or post-impact fire. Both occupants were properly restrained with three-point safety harnesses and sustained no injuries. The probable cause of the accident was the helicopter's vertical impact with the ground following the pilot's loss of control during a hover. A contributory factor was the failure of the instructor to react by taking over control of the helicopter, as the aircraft could be flown with the hydraulic switch in the off position.