Aircraft proximity event between a Piper PA-44, VH-CZH and a Mooney M20, VH-DJU, near Rottnest Island Airport, Western Australia, on 5 October 2013

On 5 October 2013, a Piper PA-44 aircraft, registered VH-CZH (CZH), was enroute to Rottnest Island, from Perth, Western Australia, to conduct instrument flight rules (IFR) navigation aid (navaid) training. On board were a flight instructor and student.

There was other IFR training aircraft on the Rottnest Island common traffic advisory frequency (CTAF) when CZH arrived over the navaid to commence the practice non-directional (radio) beacon (NDB) training. Both the instructor and student made frequent broadcasts on the CTAF to advise other traffic of the aircraft’s position and their intentions. The weather was instrument meteorological conditions and conditions were deteriorating as a large cold front was moving rapidly in from the south-west.

At about 1509 Western Standard Time (WST), as CZH was inbound in the holding pattern at 2,000 ft, Perth Centre air traffic control (ATC) advised the crew that an IFR Mooney M20 aircraft, registered VH‑DJU (DJU), was inbound to Rottnest Island, and would be on descent from 3,000 ft, for instrument navaid training. The estimated time of arrival overhead the NDB would be 1518. The instructor in CZH acknowledged this traffic information.

Shortly after, the instructor and student in DJU requested a descent to 2,000 ft due to severe turbulence at their current level. This descent took DJU from controlled to uncontrolled airspace and thus a change from ATC separation responsibility, to pilot responsibility for maintaining separation in the Rottnest Island area.

When the crew in CZH had not heard from DJU on the CTAF, the instructor tried unsuccessfully to raise them on this frequency. He then contacted ATC on the Perth Centre frequency, who provided traffic information. The pilots subsequently arranged mutual separation

The ATSB SafetyWatch campaign highlights the broad safety concerns that come out of our investigation findings and from the occurrence data reported to us by industry. One of the safety concerns is safety around non-controlled aerodromes. Insufficient communication between pilots, and breakdowns in situational awareness were the most common contributors to occurrences in the vicinity of non-controlled aerodromes.

Aviation Short Investigation Bulletin - Issue 26