What happened
On 17 April 2018, an Embraer ERJ-135LR, registration ZS-ALO, was operating a scheduled domestic flight from Cape Town International Aerodrome to Wonderboom Aerodrome. The flight, carrying 3 crew members and 29 passengers, was conducting an IFR approach to runway 29 under visual meteorological conditions.
As the aircraft approached the aerodrome, the crew noted a busy circuit containing several training aircraft. While attempting to position for the approach, the crew found themselves on a late downwind/base leg. During the final approach, the crew observed a Cessna 172, registration ZS-OHN, approximately 2nm ahead of them.
The situation escalated when air traffic control cleared the slower Cessna for a touch-and-go maneuver ahead of the Embraer. Recognizing that the separation between the two aircraft was no longer safe, the crew of ZS-ALO initiated an immediate go-around. To avoid a potential mid-air collision with the slower VFR traffic in the right-hand circuit, the crew executed a non-standard left-hand turn. Following the maneuver, the aircraft re-joined the approach and landed safely without further incident.
The investigation
The investigation examined the sequence of events leading to the loss of separation and the actions taken by both the flight crew and air traffic control. Investigators reviewed the flight's arrival procedures, noting that the crew had to perform a wide teardrop maneuver to join the circuit. The investigation also looked into the instructions provided by the tower, specifically noting that the controller cleared the slower traffic for a touch-and-go despite the presence of the approaching commercial jet. Furthermore, the investigation noted that the air traffic controller did not verify the exact position of the Embraer before issuing the clearance for the preceding aircraft.