National CFZ network: A Canadian alternative?

24 April 2013 / by the GAA team / Consultation, Safety

One of our readers with experience of flying in Canada has contributed the following:

“In Canada, unattended airfields are on the same frequency, which is 123.2, like our 119.1. But they only use it within 5 nm from the unattended airfield. Outside of that 5 nm, we go onto a transit frequency of 126.7 which is used for air-to-air and everyone should be on that.

Best part is, if you are wanting to talk to someone at a Flight Information Region, it is on the same 126.7 air-to-air as well but you hit the transmit button (I think it is 7 times within 3 or 4 seconds) and it sounds like you are making a phone call, which it is: a cellphone link via aviation frequency. You get connected to flight service and talk as per normal on the radio. Everyone in the area can hear the conversation; all the while you are maintaining a listening watch on the air-to-air, it’s all on the one frequency. Once your conversation is over, flight service closes the link so they don’t get bugged with the general air-to-air radio calls and chit-chat.

[Editor: This cell service is only available in mountainous areas, which is of particular interest to us Kiwis…]

Flight Service can also open the link in a specific area to give out reports and warnings etc.

This way, there are only two frequencies (Airfield or Transit) and it is clear when to be on those frequencies, yet still get all the information you want when needed with the one radio box. These same frequencies are used right throughout Canada, as I understand it, in Class G airspace.

Which is unlike NZ, where here we have about 10 or 11 different frequencies throughout the country to get general flight information when in transit in Class G airspace. What we could do in those 10 or 11 areas: be all on the same frequency still, but have a phone call link as in Canada, to talk to Christchurch Info.”

In response to this, GAA has done some preliminary research on the Canadian equivalent of FISCOM.

The Canadians are in the process of re-designing their Flight Information Service and have identified their problems as:

♦ In most areas of the country FISE services (Flight Information Service En-Route) were provided on one frequency, 126.7 MHz.

♦ This is also the frequency designated for use by pilots (both VFR & IFR) to broadcast their position and intentions while operating in uncontrolled airspace. A large demand for FISE service in combination with high levels of pilot broadcasts has resulted in frequency congestion and interference on 126.7 MHz. This has an impact on the safety of flight operations. In addition, some RCOs (Remote Communication Outlets) are close enough that they interfere with each other or result in coverage overlap while in some areas of the country there are large gaps in RCO coverage.

The Remote Communication Outlet System

A Remote Communications Outlet (RCO) uses VHF transmitters/receivers to provide a remote communications link between pilots and Air Traffic Services (ATS) facilities. Flight service specialists at Flight Information Centre (FIC) facilities use the RCOs to communicate with pilots and provide the following services:

♦ FISE (Flight Information Service Enroute), which includes the provision of aviation weather information, NOTAMs, accepting flight plans, position reports and pilot reports (PIREPs)

♦ Aeronautical broadcast service, which consists of broadcasting information that could impact flight safety but that may not have been available to the pilot prior to takeoff, such as SIGMETs and urgent PIREPs

♦ Communication searches by flight service specialists to determine the status of an overdue aircraft and

♦ Relay IFR clearances, wind and altimeter information to conduct an instrument approach and special VFR authorisations at aerodromes within control zones.

The solution to the Canadian problem

To resolve the safety concerns and to improve the overall provision of flight information service, NAV CANADA is redesigning the RCO system as follows:

♦ Five frequencies dedicated to FISE (122.375, 123.275 MHz, 123.375 MHz, 123.475 MHz and 123.55 MHz) will be used for most RCO sites.

Note that radios do not need to display to three decimal places to use these new frequencies. For instance 123.275 = 123.27 (See TC AIM – COM 5.3)

♦ RCOs will be located approximately 220 nm apart, along airways, air routes and VFR flyways. The 220 nm separation guideline was based on a requirement for a pilot to get a weather information update once an hour while flying an aircraft at 3000 feet above ground at 120 knots. In mountainous areas, spacing of RCOs will be closer in
order to meet coverage requirements for VFR flyways in valleys.

♦ At most RCO sites where a discrete FISE frequency has been established, FIC flight service specialists will no longer monitor 126.7 MHz. However, they will have the ability to transmit and receive on 126.7 MHz, when required, to provide the aeronautical broadcasting service (safety messages such as SIGMET, urgent PIREP) and to conduct communication searches for overdue aircraft. Note that when the FIC selects 126.7 MHz, the FISE frequency transceiver is activated also, resulting in simultaneous broadcast on both frequencies. RCO sites with this configuration for 126.7 MHz will be published in the CFS and on maps and charts as “126.7 (bcst)”.

♦ At a few sites where lower traffic levels and less demand for FISE permits, 126.7 MHz will remain the sole frequency for both FISE and aeronautical broadcasts.

♦ Some new RCOs will be established and some will be decommissioned in order to provide more uniform and effective en route communications coverage.

Rather than re-invent the wheel, as we are apt to do in our New Zealand CAA, some more research should be carried out into the way the Canadian system works, to determine if it may be an alternative solution to our problems.