The Australian Transport Safety Bureau did not conduct an on-scene investigation of this occurrence. The report presented below was prepared principally from information supplied to the Bureau.
REPORTED INFORMATION
On 4 December 2004, at approximately 1407 western standard time, a Robinson Helicopter Company R22 (helicopter) became airborne from the helipad adjacent to runway 06 left (L)/24 right (R) at Jandakot Airport. The helicopter departed in a south-westerly direction parallel to runway 24 and continued on that track. The pilot reported that he planned to depart the Jandakot circuit area to the south-west of the airport at 1,000 ft. While the helicopter was climbing on that south-westerly track, a Cessna 172R (C172) became airborne off runway 24R at Jandakot. The Jandakot control zone was operating under the General Aviation Airport Procedures (GAAP) at the time of the occurrence.
The C172 pilot reported that he had planned to depart the Jandakot circuit area on a north-westerly track. That track required a right turn from runway 24R, across the track of the departing helicopter. When the two aircraft were at an altitude of approximately 600 ft, the pilot of the C172 reported to the Jandakot aerodrome controller (ADC) that he had a helicopter in sight to his right. The ADC advised the pilot of the C172 to pass behind the helicopter. The pilot of the C172 acknowledged that broadcast and commenced a right turn.
The Aeronautical Information Publication (AIP) ENR 1.1, 25.1.1 stated that:
A pilot must:
- sight and maintain separation from other aircraft whilst operating in a GAAP control zone;
- comply with ATC instructions while ensuring that separation is maintained from other aircraft;
- advise ATC immediately if unable to comply with a control instruction;
- advise ATC if unable to sight, or if sight lost of, other aircraft notified as traffic.
The AIP ENR 1.1, 26.1 stated that:
Traffic information shall be issued by ATC when:
- the pilot of one aircraft was required to give way to, follow, or otherwise adjust the aircrafts flight path relative to that flown by another aircraft.
The ADC did not pass traffic information to the pilot of the C172 when he cleared that aircraft for take-off, because he believed there would be sufficient spacing to allow the C172 to pass behind the helicopter.
The instructor pilot of the helicopter reported that the C172 was in his 10 oclock position at the same altitude when the C172 pilot requested a right turn. He also reported that once the C172 pilot commenced the right turn, both aircraft would have collided if he had not taken evasive action that involved a rapid descent and a steep turn.
The pilot of the C172 reported that the helicopter was in his 2 oclock position when he requested the right turn. He subsequently commenced the right turn because he considered that it was safe to do so. He believed he would pass behind, and well clear of, the helicopter.
The ATSB was unable to determine the proximity of the two aircraft from recorded radar data due to the radar coverage limitations in the Jandakot circuit area. Therefore, the ATSB was unable to resolve the difference between the recollections of the helicopter pilot and the C172 pilot.