What happened
On the morning of 8 November 2023, a collision occurred between two Cessna 172M aircraft on Taxiway Delta at Wonderboom Airport (FAWB). The first aircraft, ZS-SPO, was being operated by a student pilot for training purposes. The second aircraft, ZS-SLY, was occupied by two pilots preparing for a private flight to Vereeniging Airport.
While taxiing toward the Runway 11 holding point, the student pilot encountered ZS-SLY stationary on the taxiway, as the crew was performing engine power checks. Unsure of how long the checks would last, the student pilot attempted to maneuver around the stationary aircraft. During this movement, the left wingtip of ZS-SPO struck the right wingtip of ZS-SLY. The impact caused minor damage to both aircraft, but no injuries were reported to the occupants of either plane.
The investigation
An investigation by the SACAA AIID established that the incident took place under clear, visual meteorological conditions. The investigation examined the movements of both aircraft and the procedures in place at the aerodrome. It was noted that while the student pilot was following instructions from air traffic control to proceed via Taxiway Foxtrot and across Runway 06, the encounter occurred on Taxiway Delta.
Investigators looked into the operational environment at Wonderboom Airport, noting that because there is no designated run-up area near Runway 11, pilots frequently use Taxiway D for engine power checks. The investigation also reviewed the flight experience of the pilots, noting the student pilot had approximately 40 total flying hours, while the pilot of the stationary aircraft had 123 hours.
Findings
- The primary cause of the collision was the left wing of ZS-SPO impacting the right wing of the stationary ZS-SLY.
- A significant contributing factor was that the student pilot misjudged the clearance distance between the two aircraft wings during the maneuver.
- The lack of a designated engine run-up area near Runway 11 led to the use of a taxiway for power checks, which increased the risk of conflict with taxiing traffic.
- The investigation suggested that taxiing around stationary aircraft may have become a normalized deviation in local operations.