Australian investigators have been unable to identify the object involved in an airprox with a de Havilland Canada Dash 8-300 on approach to Perth in March.
But it has not discounted the possibility that it was an unmanned aerial vehicle, although no military UAV activity was taking place at the time.
Operated by Skippers Aviation, the turboprop had been flying at about 3,800ft some 23km north-east of Perth when the crew saw a bright strobe-light directly in front of them.
“The light appeared to track towards the aircraft and the crew realised that the light was on an unknown object, possibly an unmanned aerial vehicle,” says the Australian Transport Safety Bureau.
It passed the Dash 8 with a separation of about 100ft vertically and 20m (65ft) horizontally, as the crew took evasive action by turning west. There was no alert from the aircraft’s collision-avoidance system.
The crew stated that the unknown object was “cylindrical in shape and grey in colour”, says the ATSB, adding that it was flying at 3,700ft within controlled airspace.
Although airspace below 3,500ft was a restricted military zone, the Australian Defence Force was not operating any unmanned aerial vehicles – nor aware of any in the region – at the time of the 19 March event.
None of the Dash 8’s occupants was injured. The ATSB says it was “not able to confirm the details of the object” nor identify any UAV operator.