What happened
On 19 April 2019, two Boeing 737-800 aircraft, ZS-SJH and ZS-ZWV, were preparing for departures from O.R. Tambo International Aerodrome. The aircraft ZS-ZWV was instructed by ground control to hold short on taxiway Echo to allow ZS-SJH to proceed for a full-length runway departure. During the taxiing process, the crew of ZS-SJH deviated from their assigned path, turning onto taxiway Foxtrot and eventually positioning themselves behind the stationary ZS-ZWV on taxiway Alpha.
In an attempt to maneuver behind the stationary aircraft, the crew of ZS-SJH steered away from the taxiway centerline. This maneuver resulted in a collision where the right-hand winglet of ZS-SJH struck the left horizontal stabilizer of ZS-ZWV. While the crew of ZS-SJH initially reported no contact, a subsequent inspection by ground engineers confirmed damage to the winglet of ZS-SJH and a bent static wick and damaged stabilizer tip on ZS-ZWV. There were no injuries to the occupants of either aircraft.
The investigation
The investigation examined the communications between the flight crews and air traffic control (ATC). It established that ground ATC had provided the crew of ZS-SJH with an alternative routing option via the Delta ramp and taxiway Golf 9 to safely bypass the stationary ZS-ZWV. Although the crew correctly read back this instruction, they chose to proceed via taxiway Alpha instead.
Investigators also reviewed the operational context, noting that ZS-SJH was approximately 15 minutes behind schedule due to various ground delays, including catering and passenger boarding. The crew's decision to taxi behind the stationary aircraft was made under the impression that there was sufficient clearance to pass.
Findings
- The primary cause of the collision was the crew of ZS-SJH electing not to follow the ATC-provided alternate route.
- The crew of ZS-SJH attempted to maneuver behind the stationary ZS-ZWV on taxiway Alpha, leading to the winglet impact.
- The crew's decision-making was influenced by a desire to maintain their schedule despite being behind the stationary aircraft.
- The incident was characterized by a lack of situational awareness and a deviation from standard operating procedures regarding ATC instructions.