The plane's altitude was around 65m over the stadium. There's no "unexpected turbulence" besides extreme weather conditions that are going to cause an altitude loss of 12m (the closest it got to the stadium) in a plane like Airlink's E190.
At cruising altitude different story because the air is much thinner.
We have photos and we have ADSB data showing the clearance. While more detailed data is needed, the consensus is that they were +-200ft from ground level, which is 60m from ground level.
To repaste from another post of mine -
Flight Radar 24 showed 50ft, but that has to be pressure corrected from 1013hPa.
QNH for Cape Town airport was 1018 hPa. If QNH is higher, the aircraft is higher. The vertical correction is (5x 32ft) higher = 160ft above the displayed altitude (50ft), so the aircraft was at 210ft AMSL.
The base of the DHL Stadium is 13ft AMSL. The DHL Stadium website says it is 50m high (164ft). That means the highest point is 164+13ft (177ft) AMSL. An aircraft height of 210ft gives a clearance of 33ft.
ADSB and Mode S reports height in 25ft blocks. The next 25ft is reported when the aircraft is 13ft above the previous 25ft block.
So 33ft, but somewhere between 21ft and 46ft.
This puts it under the purported 200ft approval from SACAA.
I suspect that the approval was for 200ft *above* stadium, not 200ft above ground level. We need to see plans for what was approved. Even if SACAA approved 200ft from ground level, the planes likely dipped below the 200ft above ground.
A formal enquiry will probably resolve it, if SACAA deems it necessary.