South African Airways (SA, Johannesburg O.R. Tambo) has confirmed that management has launched an internal investigation into the mainline carrier's commercial relationship with its Mango Airlines (MNO, Johannesburg O.R. Tambo) subsidiary.

In a statement confirming Mango CEO Nico Bezuidenhout's impending departure (for rival Fastjet (Dar es Salaam)), the state-owned enterprise (SOE) said an investigation into the manner in which certain routes were allocated from SAA to Mango, to the detriment of the mainline carrier, was currently underway. The move, it said, had effectively hurt SAA’s commercial interests and financial performance.

Additionally, SAA spoke about how it had subsidized Mango's operations by leasing it a fleet of ten B737-800s at a significantly discounted rate while continuing to pay market-related premiums to their lessor.

"We draw no immediate conclusions on this about who may be held accountable for this as the investigation will possibly shed light on the matter," the airline said.

Bezuidenhout, who was SAA's interim CEO in 2013 and then again in 2015, has been credited with Mango's strong financial performance which has seen it posting profits for eight out of the last ten years.

As such, SAA's parting statement is seen as an attempt to smear his legacy by implying Mango's success was purely a result of mainline subsidization and cherry-picked routes as opposed to his managerial competency.

Bezuidenhout assumes his position as Chief Executive Officer (CEO) at Fastjet with effect from August 1.