Created Wednesday, Mar 9th 2022 21:17Z, last updated Wednesday, Mar 9th 2022 21:17Z
A Kulula Boeing 737-800, registration ZS-ZWF performing flight
MN-500 from Durban to Lanseria (South Africa) with 108 passengers and 6 crew, was on a visual approach to Lanseria's runway 07 when the crew received a TCAS Resolution Advisory. The crew continued their approach and landed without further incident.
A DC-3 registration ZS-ASN was on a simulated RNAV (GNSS) approach to runway 07 about 8nm before the runway threshold and 500 feet below the Boeing when both aircraft TCAS systems issued resolution advisory instructing the DC-3 to descend.
On Mar 9th 2022 South Africa's CAA released their preliminary report summarizing the sequence of events:
During initial contact with FALA air traffic control (ATC), the ZS-ASN aircraft requested a simulated Area Navigation (RNAV)/Global Navigation Satellite Systems (GNSS) approach for Runway 07 (RWY 07). The ATC approved the request and cleared the aircraft to route to position LA1N1, below FALA Terminal Control Area (TMA) at an altitude of 6400' (feet) and on a query nautical height (QNH) of 1021. Upon reaching LA1N1, ATC cleared the aircraft for the simulated approach and advised that they report at 6 nautical miles (nm) final approach for RWY 07.
About 2 minutes and 8 seconds later, the ZS-ZWF aircraft contacted FALA ATC and requested a right visual approach for RWY 07. The ATC asked ZS-ZWF to report their radial DME LIV crossing, which was radial 215 and 14 DME. After about 20 seconds, ATC cleared ZS-ZWF for right visual approach RWY 07 at a QNH of 1021 as well as instructed them to report at 5nm final approach and that they reduce speed to the minimum safe approach.
After 1 minute and 32 seconds, ATC called and asked ZS-ASN aircraft to break off the approach to the left and re-join the late left downwind RWY 07. The ZS-ASN reported that they were 8nm final approach. They found this confusing as they were getting ready to call at 6nm final approach as previously requested. They asked for confirmation on the north bound turn, and downwind reporting. The ATC affirmed “turn left now, continue routing north”. The ATC then told ZS-ZWF to continue approach and also made the crew aware of a DC 3 aircraft that was breaking off to their left, routing north. The pilot of ZS-ZWF told ATC that he has visual of traffic.
The ZS-ASN stated that as they commenced the turn to the north, the Airborne Collision Avoidance System/Traffic Collision Avoidance System (ACAS/TCAS) displayed a Resolution Advisory (RA) with the instruction to descend immediately. A descent was initiated by the ZS-ASN crew. The ZS-ZWF aircraft approached from behind the ZS-ASN and was approximately 500' (feet) above at the time.
A few seconds later, the RA was cancelled on the aircraft, now clear of the threat. A minute and 9 seconds later, the ZS-ASN called ATC and stated that they were climbing back to their last assigned altitude of 6400' (feet) and that they had encountered an RA.
Meanwhile, the ZS-ZWF aircraft told ATC that they were on final approach. ATC told them to continue approach RWY 07 and that there was traffic which was about to vacate the runway. The ZS-ASN told the ATC that they were repositioning to late left downwind; ATC acknowledged and asked if they still wanted the GNSS/RNAV approach; the ZS-ASN opted to cancel but continued with the circuits. The ATC then cleared ZS-ZWF to land on RWY 07 and gave them the surface wind. The ZS-ASN aircraft completed three circuits before landing.
After the serious incident, the ZS-ZWF crew stated that 2nm before position LA1F1 whilst turning for final approach, they had a RA warning instructing them to climb. Corrective action was taken and, once they were clear of the traffic, they continued with final approach and landed on RWY 07.
Both aircraft were not damaged during this serious incident and both pilots, crew and passengers were not injured.
