On 31 October 2012, the pilot of a Robinson R22 helicopter, VH-HOA, was conducting mustering operations at Innamincka Station, South Australia on a hot, cloudless day.

The helicopter had been assisting ground personnel move a large mob of cattle through sandy and swampy terrain.  The pilot was tasked with flying a low-level east-west grid pattern well behind the main herd, checking for stray cattle.

The pilot’s visibility through the windscreen had deteriorated during the day, due to a build-up of dust, sand and mud. During his final run, the pilot conducted a right turn from west to east over the edge of Lake Marradibbadibba. Although wearing sunglasses, the pilot received significant sun-glare from the water. He became disoriented and did not detect a rate of descent. The helicopter contacted the water and sank. The pilot exited the helicopter without injury and swam to shore.

The effect of sun-glare when relying on visual cues has contributed to a number of accidents, and has been documented in US Federal Aviation Administration research report Sunlight and its association with aviation accidents.

Aviation Short Investigation Bulletin – Issue 15