Mode Aviation
Reference No. AR2020-00046
Date reported 18 July 2020
Concern title Frequency congestion at Ballina/Byron Gateway aerodrome contributing to frequency congestion
Concern summary

Certified air/ground radio service (CA/GRS) at Ballina/Byron Gateway aerodrome contributing to frequency congestion.

Industry / Operation affected Aviation: Airspace management
Concern subject type Aviation: Airspace

Reporter's concern

Multiple reporters contacted the ATSB with concerns that the CA/GRS has contributed to the increased frequency congestion at and around Ballina.

The reporters believe that the CA/GRS was introduced with the primary purpose of enhancing the safety of regular passenger transport (RPT) operations by providing relevant traffic information, and that the benefits of CA/GRS was for pilots to receive traffic information in specific terms for their flight, which enhances their ability to see and avoid potentially conflicting traffic. However, the reporters believe that CA/GRS operators at Ballina (Ballina Radio) routinely unnecessarily overuse the radio, passing traffic to every aircraft (and vehicle) that calls on the Ballina CTAF, which often results in over transmission of aircraft calls at Ballina, Lismore and Casino. Multiple examples were provided.

The reporters acknowledge that pilots of large RPT aircraft have an increased workload and enhanced responsibility to their passengers to ensure safety at non-controlled aerodromes. High movement volumes of general aviation and recreational aircraft can increase the risk of an airborne collision by increasing likelihood through exposure, and it is acknowledged that the CA/GRS concept appears as a risk mitigation in theory; however, in practice this becomes untrue.

One reporter acknowledged that some pilots also often relay irrelevant information on the CTAF, which contributes to the over transmissions, and there is a general lack of appropriate radio use and terminology that contributes to the frequency congestion.

The reporters state that the current CA/GRS paradigm is that all known traffic is provided to all aircraft individually as they make first contact either on taxi or inbound. This is in contrast to the controlled airspace paradigm where only traffic applicable to the flight route that requires visual acquisition by the pilot is passed. The former can result in significant transmission time to pass the details of aircraft call sign, aircraft type, position, level and intentions for each piece of traffic within 10 NM. Frequency congestion is further increased as this information is repeated as each aircraft makes first contact. After traffic information is received, pilots continue to make normal broadcasts and conduct mutual de-confliction.

Operator's response (Operator 1)

The aerodrome operator did not respond to the REPCON. However, the CA/GRS unit advised it is apparent that the issue is frequency congestion caused by four, at times, reasonably busy uncontrolled aerodromes being on the same CTAF, compounded by the location-dependant coverage that affects pilots in the CTAF  being able to hear all radio calls.

The reporters have incorrectly suggested that the CA/GRS is the problem due to their lack of understanding of the overall aviation system in place in the area.

Part of the problem relates to the location and content of calls made by pilots. All pilots make different calls, some standard, others vague and non-specific that require detailed questioning.

CASA’s CAAP 166 defines the mandatory and suggested calls for pilots to make which if followed would eliminate many of the problems reported here.

CA/GRS concur that with four aerodromes on the one CTAF there are situations where available time to transmit is limited. In addition, CA/GRS and pilots cannot hear the pilot of an aircraft call on the ground at other locations, making an over-transmit situation unavoidable.

A retransmit facility would overcome the over transmissions to a large extent and allow pilots and CA/GRS to make timely transmissions during busy periods.

Regulator's response (Regulator 1)

The OAR has undertaken a review to assess the claims made in the REPCON. The purpose of the review was to identify the issues affecting the stakeholders, the effectiveness and compliance with the mandatory radio broadcast requirements within the Ballina Broadcast Area, evaluate the impact the CA/GRS has on operations and explore alternative means of enhancing safety for airspace users.

The OAR has sought input from Airservices regarding some of the potential solutions to the issues raised by the stakeholders. The OAR will take steps accordingly to address the issues raised by the stakeholders upon receipt of that advice.

ATSB comment

Airservices is proposing to introduce enhanced traffic services, in Class G airspace, through the provision of the Surveillance Flight Information Service (SFIS) at selected regional non-towered aerodromes across Australia.

The SFIS is the provision of traffic information to IFR/IFR, IFR/VFR, and VFR/VFR aircraft operating within a CASA declared broadcast area using the aerodrome’s discrete CTAF.

All aircraft operating in the aerodrome’s broadcast area will be required to comply with existing CTAF and Class G rules and recommendations. Aircraft will also be required to broadcast their intentions, to enable the SFIS controller to provide aircrew with an enhanced traffic service, improve situational awareness, and reduce cockpit workload when operating in close proximity, during busy times.

The target implementation date for Ballina, New South Wales and Mangalore, Victoria is 12 August 2021, subject to standard regulatory processes and approvals.

More information can be found at Surveillance Flight Information Service | Engage Airservices (airservicesaustralia.com)

Last update 06 July 2021