What happened
On 3 August 1999, an Ayres S2R-T34, registration ZS-LZE, was engaged in firefighting operations near the Bhunya area in Swaziland. The aircraft was tasked with dropping multiple water loads onto a pine plantation fire. While weather conditions were generally fine with moderate winds, the area was obscured by heavy smoke from the active blaze.
During the mission, the pilot attempted an initial approach that was too high. On a subsequent attempt, the pilot successfully released the water load onto the target. However, following the release, the aircraft experienced a severe pitch-up. Witnesses observed the aircraft enter a maneuver resembling a spin, which led to a crash just beyond a hill near the drop site. A post-impact fire subsequently destroyed the wreckage. The pilot, who held a valid commercial license, was the sole occupant and was killed in the accident.
The investigation
An investigation conducted by SACAA AIID, in conjunction with the Swaziland DCA, examined the wreckage and the flight path. Investigators located the left-hand wing tip on the ground near the water release point. Additionally, a large section of the upper left-hand wing skin was found resting atop a pine tree in the same vicinity.
Further examination of the flight path, approximately 120 degrees magnetic from the site, revealed various paint flakes and small debris. This distribution of material suggested that the left-hand wing tip failed while the aircraft was still in flight.
Findings
- The primary cause of the accident was the structural failure of the left-hand wing tip.
- This failure was likely the result of an overload or a stress-overload condition.
- Visibility at the site was significantly compromised by dense smoke from the forest fire.