An Air Tractor pilot's attention was likely diverted by a spray system warning before their aircraft struck the ground during a spray run near Bourke, NSW, an ATSB final report details.
Commencing their first spray run of the day on the morning of 10 February 2024, the pilot activated the AT‑502 aircraft's spray system to disperse herbicide on the unsown field, but data reviewed during the ATSB investigation indicated that no spray flow was recorded.
"This likely triggered a visual warning on the Satloc spray system's display in the cockpit, and it was likely the pilot's attention was momentarily diverted, before the aircraft inadvertently descended into the field," ATSB Chief Commissioner Angus Mitchell said.
The descent led the aircraft's left main wheel to touch down near the edge of the field, with the aircraft travelling for a further 27 m before both landing gear wheels struck an irrigation levee that ran perpendicular to the end of the field.
The wreckage of the destroyed aircraft was found inverted in an adjacent cotton field, at the end of a ground scar and wreckage trail that aligned with the final data point recorded on a track of about 160°. The pilot was fatally injured, and the aircraft was destroyed.
Subsequent wreckage examination by ATSB transport safety investigators indicated the aircraft originally contacted the ground nose down, before coming to rest inverted. No pre‑impact defects were identified, nor was there evidence of bird strike or in‑flight break-up.
GPS data from the Satloc system showed that the aircraft was positioned at a height between 10 ft and 22 ft above ground level when the spray system was activated at the start of the run, but no spray flow was recorded.
For 40 seconds, the aircraft maintained the same heading during the run tracking in a south‑easterly direction with a ground speed between 112 kt and 115 kt and a height between 4 ft and 22 ft. A final data point recorded the aircraft as having a ground speed of about 115 kt, a height of up to 7 ft and maintaining heading.
Shortly after this point, the aircraft contacted the ground.
"This tragic accident is a reminder that unexpected alerts can divert a pilot's attention from the primary task of flying the aircraft," Mr Mitchell said.
In this accident, with the aircraft flying at 120 kt and around 10 ft, in one second the aircraft would travel around 60 m, and even the smallest change in attitude could be imperceivable but still result in a collision with terrain.
"Given the limited height and time available during low‑level operations, even a momentary change in focus of attention can have a significant consequence," Mr Mitchell continued.
"When possible, pilots should climb the aircraft when receiving any unexpected alerts, before conducting troubleshooting of a potential system failure at a safer height."
You can find here the final report: Collision with terrain involving Air Tractor AT-502, VH‑AQW, 17 km south-west of Bourke Airport, New South Wales, on 10 February 2024
