Niekerkshoop

On 22 April 2014 at approximately 0716Z the Commercial pilot accompanied by a passenger departed Cape Town International Airport (FACT) on an IFR flight to Swartwater in the Limpopo Province. Approximately 16 minutes after take-off with the aircraft climbing through an altitude of 13500 feet to 17000 feet, the Air Traffic Controller advised the pilot that the aircraft’s Mode C transponder started transmitting erroneous altitude data and indicating that the aircraft was descending whereas the pilot thought he was ascending. The pilot notified the ATC that the aircraft was not descending and attempted to rectify the problem by recycling the Mode C transponder that however didn’t resolve the problem. As the transponder information was intermittent during the IFR flight to Swartwater, the ATC requested the pilot to descent to the VFR flight level FL 135. The pilot then requested Area West for approval to ascent to flight level (FL 195) which was approved. It appears that the pilot was unaware that the pitot static tube system that supplies both pitot and static air pressure for the airspeed indicator, altimeter and triple indicator was most probably blocked by dust or sand. The aircraft exceeded the Maximum Structural Air Speed (VNO) of the aircraft and the VNE air speed of 1 hour 44 minutes and 9 minutes respectively. The VNO of 173 airspeed and VNE of 203 airspeed exceedance resulted in the catastrophic inflight breakup of the aircraft. The wreckage was found scattered in a 1.58km path in mountainous terrain. Both occupants on board the aircraft sustained fatal injuries.