From the CASA consultation report:
More than eighty per cent of respondents to the discussion paper supported establishing MULTICOM 126.7 MHz as the frequency to use in low level airspace.
Clearly the likelihood of increased congestion on 126.7 should have been considered, both by respondents and CASA's assessors of the proposal.
The problem occurred during the Class G Demonstration way back in 1998.
A partial quote from that report:
2.2 Operational Safety Factors
- The operation of the national advisory frequency was associated with regular occurrences of frequency congestion and over-transmission. The extent of those problems fluctuated from day to day, but on average did not decrease significantly over the period of the demonstration.
- Pilot workload generally increased during the demonstration, particularly for single-pilot instrument flight rules operations. The main factor contributing to the higher workload was the need for pilots to use multiple radio frequencies.
Theoretically, the VHF range for aircraft to aircraft both @ 5000ft is about 140km
