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Mode Aviation
Reference No. AR201400080
Date reported 19 September 2014
Concern title The use of Multicom(126.7) versus Area Frequency
Concern summary

The concern related to the lack of understanding by CASA as to the implication of minor changes to the AIP to aviation in regional areas.

Industry / Operation affected Aviation: General aviation
Concern subject type Aviation: Airspace

Reporter's concern

The reporter expressed a safety concern relating to the lack of industry education and consultation which was conducted by CASA when changes were made to the procedures in the Aeronautical Information Package (AIP) in 2013.

This was a minor change in the wording within the procedures requiring pilots to make broadcasts on the Area frequency, at aerodromes which are not marked on maps, rather than the Multicom frequency, 126.7 Mhz.

The reporter believes that this change has had far reaching implications in remote area flying. As this change has not been widely publicised within the broader aviation community; it has led to the situation where pilots who have not been informed of the changes, broadcasting on Multicom 126.7 and pilots who are aware of the changes using the Area frequency. The reporter advised that due to the lack of education and awareness activity, most pilots across Northern Queensland, where the reporter routinely flies, operate on the Multicom frequency 126.7 at all times when operating below 5,000 ft, unless within the vicinity of an airfield with a designated common traffic frequency (CTAF). This is to maintain situational awareness due to the high number of approved landing areas (ALAs) on properties in remote areas. The reporter advised that although the AIP requires operation on the Area frequency, except when operating in the vicinity of designated CTAF areas, broadcast areas or airfields marked on charts, they have elected to operate on the Multicom frequency because that is what nearly all other traffic is routinely operating on.

This is further complicated by AIP Enroute (ENR) 1.1 21.1.10 which states that aircraft may maintain a listening watch on other than Area VHF for operations below 5,000 ft in Class G airspace such as parachuting, gliding, agricultural operations and circuit training or local flights at non-controlled aerodromes. This does not specify what frequency pilot’s should be broadcasting on and further creates a situation where pilots operating at bush strips can legally be broadcasting on other than Area frequency, while those following the new procedure will be maintaining a listening watch on Area frequency.

Reporter comment: These changes, along with the lack of an education campaign, have created a situation where no-one is sure which frequency to use when operating below 5,000 ft in remote areas to ensure they are operating on the same frequency as other nearby aircraft.

Regulator's response (Regulator 1)

In respect of the issue of radio broadcast frequencies at non-controlled aerodromes it should be noted that for VFR aircraft, VHF radio is only required for: operations above 5,000 ft AMSL, at aerodromes where carriage and use of radio is required; or for operations in reduced VMC (AIP ENR 1.4 4 refers). As a result, CASA has provided guidance to ensure where VFR pilots of VHF equipped aircraft are maintaining a listening watch and where necessary making broadcasts, they do so on a frequency that other aircraft in the vicinity are also monitoring.

CASA has noted the reporter’s assertion that most pilots across a broad geographical area are operating on multicom below 126.7 while flying cross country. CASA does not recommend that VFR aircraft do this. The reason is multicom is not a frequency that can be monitored by air traffic control. As a result, when pilots of VFR aircraft are monitoring this frequency they are unable to receive an air traffic service such as safety alerts or a surveillance information service. These services are provided on Area frequency.

It is acknowledged that AIP ENR 1.1 21.1.10 could be taken to be inconsistent with the CASA advice for frequency use for circuit training and local flights at non-controlled aerodromes. However, it should not be read to suggest that transiting flights may maintain a listening watch on multicom or any other frequency other than Area VHF. Nonetheless, CASA is amending this paragraph for consistency with recent amendments.

CASA has taken a number of steps to ensure the aviation community is aware of its policy for radio broadcasts at non-controlled aerodromes as follows:

  • Amended relevant sections of the AIP;
  • Revised CAAPs 166-1 and 166-2 to reflect the policy;
  • Updated the relevant pages and products on its website and deleted outdated material;
  • Run a campaign through nationwide seminars by CASA Aviation Safety Advisers;
  • Placed articles in recent CASA Briefings – August 2014 ‘Get on the right frequency at unmarked aerodromes’ and September 2014 ‘No reports of area frequency congestion’; and
  • Issued a NOTAM to raise awareness of the changes prior to their incorporation while changes have been made.

CASA is also preparing articles for its bi-monthly publication Flight Safety Australia and producing a safety promotion video on the CASA YouTube channel explaining the policy.

The situation the reporter has described does sound like a broadcast area, and CASA has provided guidance in much of the education material listed above how such an area can be established to provide a common frequency for a number of aerodromes.





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Last update 15 May 2015