Investigators were still conducting an investigation into two smoke incidents involving the South African Civil Aviation Authority’s Cessna Citation II flight-inspection jet before its fatal loss near George.

There is no immediate evidence of a connection between the incidents – on 7 and 8 November last year – and the 23 January crash, but the SACAA had yet to reach conclusions on the cause.

In its preliminary findings the SACAA said the crew had executed a go-around at Wonderboom airport on 7 November and reported smoke in the cockpit.

After landing an inspection of both engines revealed no oil visible on the dipstick of the left-hand Pratt & Whitney JT15D-4 engine.

Maintenance personnel performed checks and, after a ground run on both powerplants, signed off the defect and returned the jet to service.

But during the take-off roll from Lanseria airport the following day, the crew again experienced smoke in the cockpit and aborted the departure. Both main landing-gear tyres deflated during the incident.

The preliminary inquiry does not identify a reason for the smoke incidents – although it says there was no evidence of fire. It states that the Citation’s certificate of airworthiness was valid to 30 October 2020.

None of the three crew members of the aircraft survived after it crashed in mountainous terrain after taking off from George airport on 23 January.