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The unexpected position of wires, glare from the sun, and ineffective reconnaissance led to an Apex Helicopters-operated Robinson R44 striking wires and crashing, according to a new report from the Transportation Safety Board of Canada (TSB).
The lone pilot on board sustained serious injuries in the crash, which took place on July 25, 2021, in Brantford, Ontario.
According to the Sept. 29 investigation report, the R44 pilot was conducting an airborne reconnaissance that morning before spraying the fields at altitudes of less than 100 feet (30 meters) above the crops. Shortly after the first spray run, the aircraft struck wires at the southeastern part of the field and crashed about 270 feet (82 meters) away.
“The wires that were struck were significantly less prominent [than two other sets of wires in the area],” the TSB report stated. “Instead of running along a roadside or the church driveway, they ran along the edge of a corn field, which is not where pilots expect to see them, nor where they focus on scanning for hazards.”
The wires were also lower than other nearby wires, and the bases of the poles carrying them were obscured by corn.
Accident investigators said the pilot’s vision may have been impacted by the position of the sun, which, just after sunrise, was almost directly in front of her flight path.
The sun’s glare, in addition to a possible film of spray fluid, dirt, or debris on the helicopter’s windshield, could have played a role in affecting the pilot’s forward visibility that morning, according to the report.
“The pilot likely would have had to focus her attention to the side of or below the direct sunlight to avoid looking into the glare,” the TSB report stated. “When flying low to the ground in a helicopter, not being able to see straight ahead makes detection of objects, such as wires, very difficult.”
Investigators also called attention to the terrain, which sloped down from west to east and lowered in elevation by about 30 feet (nine meters). Recreating the final moments of the flight that morning, accident investigators assumed the pilot would have been descending during the spray run, focusing her attention on the changing altitude and reducing the time she had to detect and avoid the wires.
And because the wires were strung between poles that were 38 feet (11 meters) above ground, it was likely they weren’t visible above the horizon until late in the spray run.