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First published March/April 2017. Story updated May 2021.

The airwaves in CFZs are becoming cluttered with irrelevant chit chat, and conversely, some pilots are still flying through MBZs without making reports.

Too much noise

Common frequency zones (CFZs) were established to encourage pilots to use a single frequency within a particular area of airspace.

They signify areas of concentrated aviation activity, especially recreational aviation and are depicted on VNCs with a diamond-shaped boundary marking, and the abbreviation “CFZ”.

It isn’t mandatory to use a radio within a CFZ, but as the CAA’s GAP booklet, New Zealand Airspace, says, “…it would be very poor airmanship not to use the published frequency and not to comply with expected local radio procedures when radio- equipped. As a minimum, pilots should broadcast their position and intentions on entry and exit from a CFZ.”

Despite that, a rising number of pilots use the frequency to have a non-essential yak.

“Pilots should follow appropriate radio discipline,” says Hamish McCoy, CAA Senior Technical Specialist. “Generally, this is making an initial position report when entering which will allow other pilots to know where they are, and their intentions. If another pilot reports on the frequency in the vicinity of where you are operating, then make a position report. Other than that, they should keep quiet, and maintain a listening watch.

“If they want a yarn, the appropriate aircraft to aircraft ‘chat’ frequency, throughout the country, is 128.95 MHz.”

There’s been a rising number in the last decade of what are known as “pilot position reporting deficiency incidents” – 42 in 2006, 112 in 2016. At least some of the total 783 reports between 2006 and so far in 2017 involve inappropriate, or no, broadcasts inside the common frequency zone.

“It’s a fine line how many radio calls a pilot should make in the CFZ,” says Carlton Campbell, CAA Aviation Safety Adviser.

“While pilots should make them at recognised reporting points, and on entering and leaving the CFZ, some pilots make position, height and intention reports far in excess of what is necessary.

“The result of that is a jumble of reports, which can become confusing, and counter-productive to safety.”

Carlton says it’s about making calls to enhance the mental map of other traffic, and not adding to the ‘noise’.

“The other crucial thing to remember is that radio calls do not replace looking out the window. Some pilots seem to think the more calls they make, the safer they’ll be. That is a false sense of security.

“There’s also inappropriate use of the 119.1 MHz frequency, as an enroute frequency, rather than an unattended aerodrome frequency, for which it was established.”

Hamish McCoy says pilots making the proper radio calls on the correct CFZ frequency, should also keep looking outside the cockpit.

“Never assume other pilots know where you are. They could be NORDO, or on another frequency. ‘See and avoid’ still applies.”

The wrong noise

Some pilots say they’re confused about when to say the name of the CFZ – for instance, ‘Rangitikei’ – and when to use the name of an aerodrome within the CFZ – for instance, ‘Feilding’.

The idea is to alert traffic in the same vicinity to look out for you.

“That way,” says Hamish McCoy, “it’s directed communication. Someone on the same frequency but who’s working further away from you, can tune out.

“I’d recommend changing at about 10 NM out. If you’re travelling two miles a minute, you’re only five minutes from being overhead. So using ‘Feilding traffic’ lets those pilots already in the circuit know that you’ll soon be joining them.

“If you’re transiting within 5 to 10 NM of an aerodrome, it’s also good flying practice to give the aerodrome traffic a call, and let them know you’re around.”

Too little noise

If there’s too much ‘noise’ on the CFZ airwaves, in some mandatory broadcast zones (MBZ), there’s too little communication.

While the obligations associated with a CFZ are voluntary, those associated with an MBZ, are, as the name suggests, compulsory.

“Many MBZs have been established at locations where there is scheduled passenger transport aircraft services on IFR operations, such as at Whakatane,” says Hamish McCoy. “That means when those aircraft are descending into, or taking off from, an aerodrome, they’ll know what traffic is in the vicinity. If they’re IMC, they need to be sure that when they break out of cloud, they’ll know where the traffic should be.

“Other MBZs have been established where there are special operations. For instance, at Parakai, where there’s lots of parachuting, or at Whenuapai, which becomes an MBZ when the tower is closed.

“We believe that pilots failing to report their position when they’re inside a mandatory broadcast zone is a problem, because we get regular reporting of such occurrences from Paraparaumu. There’s an aerodrome flight information service provided there and the flight service specialist can see the aircraft flying through the airspace and not making radio contact.

“We have to assume this happens in other MBZs, but where there is no-one based there to witness it happening.

“More importantly, other pilots will assume there is no-one to look out for, if there are no radio calls.”

The maximum interval of time between radio broadcasts varies around the country, so pilots should check, as part of their preflight planning, the visual navigation chart or the enroute section of the AIP.

For added safety, if an aircraft is equipped with anti-collision and/or landing lights, they must be switched on when operating within an MBZ and ensure your transponder is on to be electronically visible to aircraft equipped to see you.

Read rule 91.135 for details of your radio broadcast obligations inside an MBZ.

It’s free

Another under-utilised radio frequency is the FISCOM service.

“Some pilots won’t use it because they think – mistakenly – that Airways charges for the service,” says Hamish.

“But it’s free, and the flight service operator provides invaluable traffic and general information, new NOTAMs, and weather updates. It also guarantees that someone will respond if you have to make an emergency call.”

Whichever frequency pilots are on, Hamish says they should never think radio calls replace keeping a good lookout.

“Again, aircraft may be on different frequencies, without a radio, or just not transmitting. Never stop looking out the window.”

Be aware that IFR aircraft operating outside controlled airspace are not necessarily monitoring the CFZ frequency. This is because the pilots are required to be operating on FISCOM to receive IFR traffic information, and the second radio will be monitoring the control frequency – especially if still within surveillance cover – for updated surveillance flight information.

For more reading, email for a free copy of the booklets Plane Talking and New Zealand Airspace.

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