What happened
On 14 August 2011, two Piaggio P166S Albatross aircraft, registered as ZS-NJX and ZU-MMI, departed Tzaneen Aerodrome for Rand Airport. The aircraft were flying in formation as part of a private flight, likely transporting passengers following an airshow held in Tzaneen the previous day.
During the flight, the aircraft entered an area of thick, low-level clouds. A witness in the Lekgalametse Valley reported seeing the aircraft fly overhead before they disappeared into the cloud cover, followed shortly by the sound of a loud impact. The two aircraft struck a mountain at an elevation of approximately 5030 feet AMSL. A post-impact fire destroyed both airframes, and all 13 people on board—comprising two pilots and 11 passengers—were fatally injured.
The investigation
SACAA AIID investigators examined the wreckage and recovered communication transcripts. The investigation established that both aircraft were operating within their weight limits and that the engines were under power at the moment of impact, suggesting no mechanical failure was responsible.
Investigators noted that the minimum sector altitude (MSA) for the area was 9300 feet, significantly higher than the 5030 feet at which the collision occurred. Communication transcripts between the two pilots revealed an uncertainty regarding whether it was safe to transit the valley. Furthermore, the investigation found that no flight plans had been filed for either aircraft, and the wreckage was not located until two days after the accident due to adverse weather conditions.
Findings
- The primary cause of the accident was controlled flight into terrain.
- The pilots were flying in low cloud conditions that obscured the terrain.
- There was a lack of proper flight planning, as no flight plans were filed.
- The pilots demonstrated an element of doubt regarding the safety of transiting the valley, yet proceeded into the obscured area.