The Australian Transport Safety Bureau (ATSB) has issued a warning about circuits at uncontrolled airports after completing an investigation into the collision of an aeroplane and a helicopter at Caloundra.
Guimbal Cabri G2 VH-LTO and Extra 300 VH-EXR were both operating at Caloundra in September last year when they collided on the runway after landing. No-one was hurt but both aircraft were damaged.
The ATSB report found that the pilots in EXR were not aware that LTO had completed a stop-and-go on runway 12 and was still occupying the runway. The Extra struck the helicopter from behind, embedding the G2's left skid in the leading edge of the wing and destroying the propeller. The G2 suffered several strikes from the Extra's prop.
“The ATSB found the pilots of the Extra did not expect the helicopter to join the 1000-foot circuit pattern, and did not assimilate the helicopter pilot’s radio calls into their mental models of the current operations at the airport," said ATSB Director Transport Safety Stuart Macleod. "As a result, they were not aware that the helicopter was ahead of them in the circuit."
The ATSB also identified that, on the final leg of the circuit, the pilots of EXR were focused on a Sling 2 in the circuit ahead of the helicopter, and which they had been in radio communications with. The pilots had nominated themselves as No.2 for landing.
“While the pilots visually scanned the runway prior to landing, they were not aware of the helicopter’s presence, and they perceived a different aircraft to be the next ahead of them in the circuit, which resulted in them not sighting the helicopter and continuing the approach to the runway,” Macleod said.
The high nose attitude of the Extra on landing also obscured the Cabri ahead of them on the runway.
“Around CTAF and uncontrolled airports there is the possibility of aeroplanes and helicopters conducting movements that might not be considered commonplace," Macleod said. "This investigation highlights that multiple options are available to helicopters at non-towered airports, including the active 1000 ft circuit pattern.
“The alerting provided by radio broadcasts at non-towered airports such as Caloundra greatly assists the process of sighting traffic that might be a collision risk.
“This accident reinforces that, even for experienced pilots, visual identification of unknown traffic is difficult.”
The full accident investigation report is on the ATSB website.