Aircraft proximity event involving two R22 Helicopters, VH-HQJ and VH-IAY, and an unknown aircraft, 48 km east of Broome, Western Australia, on 16 September 2014

On the 16 September 2014, two Robinson R22 helicopters, registered VH HQJ and VH-IAY, were conducting aerial mustering operations about 26 NM east-north-east of Broome, Western Australia. The two R22 pilots were working together, and had planned mutual separation using relevant ground features in the area of operations. The two R22 pilots were also in radio contact on a company radio, and monitoring the multicom frequency. There was lifting fog in the area at the time, with some clear patches emerging.

At about 0745 Western Standard Time, the pilot of one of the R22s observed a light aircraft in close proximity, and advised the pilot of the other R22 that was operating some distance away. That pilot immediately looked in the direction that he thought the light aircraft may have appeared, and observed a single-engine light aircraft travelling at low level in an easterly direction. He witnessed the aircraft bank sharply towards the north, perhaps in response to having sighted the other R22 which was operating almost directly beneath the flight path of the light aircraft. Following what appeared to be an evasive manoeuvre, the light aircraft resumed its easterly track, still at low level. One of the R22 pilots tried to make contact with the pilot of the light aircraft on the multicom frequency, but without response. The light aircraft continued out of sight towards the east, and the two R22s resumed their aerial mustering operation.

Without a report from the pilot of the light aircraft, the full circumstances surrounding the incident are unclear. Nonetheless, this incident demonstrates the importance of effective communications and an effective lookout, even at low level when other aircraft may be unexpected. Furthermore, pilots should avoid operating at low level in areas where other aircraft may be engaged in aerial mustering or similar operations.

Aviation Short Investigations Bulletin - Issue 39