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Summary

Summary

Sequence of events

On 6 June 2004, at about 1520 Eastern Standard Time, the pilot of an instrument flight rules (IFR) Cirrus Design Corporation Cirrus SR20 (SR20), registered VH-SJA, was conducting a practice sector 2 entry to the Cowes VHF omnidirectional radio range (VOR) navigation aid in visual meteorological conditions (VMC). The pilot of a visual flight rules (VFR) Cessna Aircraft Company 172P (C172), registered VH-DXX, was also conducting navigation aid practice utilising the Cowes VOR and non-directional radio beacon. The Cowes navigation aids are 54 NM south-east of Melbourne Airport and the pilots were operating outside controlled airspace but within air traffic control radar coverage.

Approximately 8 NM before Cowes VOR, the SR20 pilot requested traffic information for descent to 2,000 ft. The pilot reported that he was given traffic information by the Melbourne Centre controller on a VFR aircraft at an unverified altitude of 1,900 ft. The SR20 pilot broadcast his intentions on the area frequency, 120.0 MHz and the Phillip Island common traffic advisory frequency (CTAF), 119.1 MHz. The pilot did not receive a response.

While approaching the VOR, the SR20 pilot became aware of an aircraft on a reciprocal track at the same altitude of about 2,000 ft. At about the same time, the C172 pilot saw the SR20. Both pilots took evasive action by making high angle of bank right turns. Reports from the pilots indicated that the aircraft passed in close proximity and it was estimated that the distance between the aircraft was 200 m horizontally and 50 ft vertically. The occurrence was classified both as an Airprox1 and a serious incident.

After the aircraft passed, the SR20 pilot attempted to contact the C172 pilot by radio on 120.0 MHz. There was no response from the C172 pilot. Several minutes later, the C172 pilot contacted the Melbourne Centre controller on 120.0 MHz to request traffic information. The controller provided the pilot with traffic information on the SR20.

The C172 pilot reported that he had 135.7 MHz selected at the time of the occurrence. That frequency was the nominated frequency for operating within 40 NM south and south-east of Melbourne Airport. Consequently, he was unable to hear the inbound radio transmissions of the SR20 pilot and develop an awareness of a possible conflict. The C172 pilot stated that the radio frequency of 120.0 MHz and its boundary was not published on the Melbourne Visual Navigation Chart (VNC) or on the Melbourne Visual Terminal Chart (VTC). It was also unclear on the Enroute Chart (Low Level) (ERC-L) what the appropriate frequency for the Cowes area was. The pilot was uncertain as to what frequency should have been selected when conducting airwork in the vicinity of Cowes VOR.

Before this occurrence, Airservices Australia developed an interim Frequency Planning Chart (FPC), which was promulgated by Aeronautical Information Circular (AIC) H4/04 to all licensed pilots with a current medical in March 2004. The FPC published the appropriate Air Traffic Services (ATS) class E and class G radio frequencies. However, the pilot reported that he did not receive the FPC until sometime during July 2004.

Airservices Australia has announced that it will re-introduce the publication of ATS en route class G and class E radio frequencies and frequency boundaries on Aeronautical Information Publication (AIP) charts effective 25 November 2004. Those charts include visual navigation charts, such as the VTC and VNC, and the ERC-L and Terminal Area Charts (TAC). AIC H13/04 provides further information on airspace and frequency management changes.

The difficulties associated with the see-and-avoid principle and the risk of mid-air collisions have been addressed in the following Australian Transport Safety Bureau reports:

  • Bureau of Air Safety Investigation (1991) Limitations of the see-and-avoid principle (BASI Research Report), Canberra: BASI.
  • Australian Transport Safety Bureau (2004) Bankstown midair collision (Aviation Safety Investigation Report 200201846), Canberra: ATSB.
  • Australian Transport Safety Bureau (2004) Flying training accident at Moorabbin (Aviation Safety Investigation Report 200203449), Canberra: ATSB.
  • Australian Transport Safety Bureau (2004) Review of midair collisions involving general aviation aircraft in Australia between 1961 and 2003 (Aviation Research Paper B2004/0114), Canberra: ATSB.
  • Australian Transport Safety Bureau (2004) National Airspace System Stage 2b: Analysis of Available Data (Aviation Research Report B2004/0076), Canberra: ATSB.
  • Australian Transport Safety Bureau (2003) Airprox incident between Cessna 421 and Boeing 737 (Aviation Safety Investigation Report 200304963), Canberra: ATSB.
  • Australian Transport Safety Bureau (2003) Airprox serious incident between Tobago and Boeing 737 (Air Safety Occurrence Report 200305235), Canberra: ATSB.
  • Australian Transport Safety Bureau (2004) Airprox incident between Lancair and Boeing 737 (Aviation Safety Investigation Report 200401273), Canberra: ATSB.

Related Documents: | Media Release |


1 An Airprox is an occurrence in which 2 or more aircraft come into such close proximity that a threat to the safety of the aircraft exists or may exist, in airspace where the aircraft are not subject to an air traffic control separation standard or where separation is a pilot responsibility.

 
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