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An ATSB report has found that a recent airspace incident was both an 'airprox' and a 'serious incident' and that after taking evasive action, a Cirrus SR20 and a Cessna 172 aircraft passed about 200 metres horizontally and 50 ft vertically from each other.

The Cirrus, operating under the instrument flight rules (IFR), was approaching the Cowes VHF omnidirectional radio range (VOR) navigation aid for instrument flight practice in visual meteorological conditions. A Cessna 172 aircraft, operating under the visual flight rules (VFR), was also conducting navigation aid practice using the Cowes VOR and non-directional radio beacon. Both aircraft were operating outside controlled airspace (in class G airspace), but within air traffic control radar coverage.

The pilot of the Cirrus contacted air traffic control and requested and obtained traffic information for his descent to 2,000 ft about an unverified aircraft operating at 1,900 ft in the area. The Cirrus pilot tried unsuccessfully to establish radio contact with the aircraft.

When approaching the Cowes VOR, the Cirrus pilot saw an aircraft on a reciprocal track at the same approximately 2,000 ft altitude. At about the same time, the Cessna pilot saw the Cirrus. Both pilots took evasive action. The pilots reported that the two aircraft passed about 200 metres horizontally and 50 ft vertically from each other.

The ATSB investigation found that the Cessna pilot had been on the radio frequency for operations within 40 NM south and south-east of Melbourne Airport. Consequently he was unable to hear the Cirrus pilots broadcasts and develop an awareness of a possible conflict.

The radio frequency for the Cowes area was not published on the charts being used by the Cessna pilot. Airservices Australia had published an interim Frequency Planning Chart, which published the appropriate Air Traffic Services class E and class G radio frequencies, before this occurrence. However, the Cessna pilot did not receive the chart until sometime in July 2004 after this incident.

Airservices Australia advised the ATSB that it will re-introduce the publication of en route class G and class E radio frequencies and frequency boundaries on Aeronautical Information Publication charts effective 25 November 2004.

The full investigation report (200402065) is available from the website, or from the Bureau on request.

Media contact: 1800 020 616
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Last update 01 April 2011