• CASA's NPRM would expand the size of CTAF areas and mandate 126.7 in en route Glass G airspace below 5000 feet. (CASA)
    CASA's NPRM would expand the size of CTAF areas and mandate 126.7 in en route Glass G airspace below 5000 feet. (CASA)

CASA will not go ahead with the new Multicom rules after the industry failed to support the proposal.

The NPRM proposed a move to a 126.7 frequency for all VFR Class G movements below 5000 feet and Common Terminal Area Frequencies (CTAF) of 40 nm wide.

"Overall, 42.8% of survey respondents supported the proposal and 57.2% of respondents did not support the proposal," CASA said in an announcement released today. "Respondents raised a number of important issues and concerns requiring further consideration.

"Due to the lack of support and issues raised during consultation, CASA will not implement this proposal.

"In acknowledgement of the broad support for the MULTICOM 126.7 component of this proposal, CASA is developing a new option that will be released for consultation later this month."

Over 1000 people responded to the call for feedback, and raised many Issues including:

  • the extent of overlapping CTAFs
  • frequency congestion, either on MULTICOM 126.7 or within expanded CTAF areas
  • irrelevant transmissions from neighbouring aerodromes in expanded CTAF areas
  • procedures for inbound calls
  • radio carriage and workload implications for hang gliders and paragliders.

The response from VFR pilot Michael Lewis highlights one of many issues people had with the NPRM.

"IFR flights will not be able to hear possible confliction transmissions unless they are monitoring the frequency on a second radio," Lewis said in his response. "A common CTAF will lead to frequency saturation. Pilots will not hear weather warnings broadcast on Centre frequency unless they have a second radio.

"Just because pilots are flying below 5000 ft does not change the overall safety benefits of all aircraft monitoring the area frequency. This proposal is dangerous and ill conceived."

IFR pilot James Mitchell supported the proposal broadly, but expressed reservations on how it would be work practically.

"I do however question as to how this would work with aerodromes close together having different radio frequencies, partictularly a registered aerodrome alongside one that is unregistered.

"For example, Groote Eylandt has a CTAF frequency of 126.0 whereas Bickerton Island, which is 19 nm from Groote and being an unregistered aerodrome, has a frequency of 126.7. In this sceneraio would the unregistered aerodrome adopt the 126.0 frequency because it is within a 20 nm radius of Groote or would it still retain 126.7?

"My concern would be that if it did retain the 126.7 frequency, then it wouldn't be possible to monitor and broadcast on 126.0, 126.7 and area VHF in most GA aircraft, which would be required for IFR flights under the proposed changes."

Industry sources believe that CASA's new proposal will be a "back-to-the-future" solution, hinting at a possible return to a similar system to that which existed before the NPRM was released.

More information on the NPRM status and consultation feedback is on the CASA website.



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