What happened
On the afternoon of 3 November 2021, a commercial pilot was conducting crop-spraying operations at Farm Mooipan in the Free State Province. While operating an Air Tractor AT402B, registration ZS-DZM, the pilot attempted a takeoff from Runway 35. The aircraft was heavily loaded, with the hopper tank at its full 400-US-gallon capacity and containing a pesticide mixture.
During the initial takeoff roll, the aircraft's tail lifted as expected, but upon reaching rotation speed, the pilot applied back pressure on the control stick, causing the tail to drop and touch the ground. The pilot then decided to abort the takeoff and applied maximum braking. Despite this, the aircraft could not be stopped before the end of the gravel runway. The aircraft overran the runway, striking a tree and a brick store room, which caused the aircraft to ground loop. The pilot escaped without injury, though an engine oil line ruptured during the event, causing a small fire that was extinguished with a portable onboard extinguisher.
The investigation
SACAA AIID examined the circumstances surrounding the aborted takeoff and the aircraft's performance. The investigation established that the pilot had very limited experience on this specific aircraft type, having only completed a conversion the previous day. While the pilot was experienced in radial engine aircraft, this was his first operation of a turbine-driven engine aircraft.
Investigators also looked into the operational environment. The runway used was an unlicensed strip with a hard-compacted gravel surface. The investigation found that the pilot did not utilize the hopper dump system to reduce weight during the aborted takeoff, nor did he employ reverse thrust to assist in deceleration. Furthermore, the investigation noted that the pilot had not followed the flight instructor's recommendation to undergo several hours of flight time with an empty or light load to gain familiarity with the new aircraft type.
Findings
- The pilot failed to dump the hopper load or use reverse thrust to decelerate the aircraft during the aborted takeoff.
- Commercial pressure led the pilot to bypass recommended transition training, flying with full loads immediately after conversion.
- The presence of man-made obstructions in the runway overrun area prevented the pilot from avoiding the collision with the tree and building.
- The gravel runway surface contained stones and rocks that could have compromised braking effectiveness.
- The pilot did not account for the impact of high density altitude on aircraft performance.
- There was a lack of oversight from the Air Operator Certificate (AOC) holder regarding the pilot's remote operations.
Safety action
- It is recommended that the farm owner remove all obstructions from the runway overrun area to establish a proper safety area.
- The runway surface should be cleared of stones and rocks to prevent foreign object damage and improve braking.
- The SACAA is advised to conduct inspections of the operator to ensure proper oversight of remote operations.