The reporter has raised a safety concern in relation to Broome CTAF airspace, in particular the risk of mid-air collision with aircraft departing Broome outside tower operating hours and switching to other frequencies.
As an airport with a large number of daylight general aviation Visual Flight Rules (VFR) tourism and charter operations, Broome experiences a 'rush' of departures in the 30 minutes after first light most mornings. This often results in more than 10 aircraft of varying categories departing in quick succession, often crewed by low experience pilots. While this is manageable, communication with other aircraft is an issue.
The primary concern raised is these aircraft are making a broadcast at 10 NM Broome (regardless of level passing or climbing, some stay below 5,000 ft) stating 'Aircraft xxx is 10 NM Broome changing to 126.7 and then switching from the Broome CTAF frequency to organise their own separation whilst they are operating in Class G and in some instances Class E airspace and not in the vicinity of an uncontrolled aerodrome. Furthermore, many of these aircraft are flying along busy Instrument Flight Rules (IFR) routes, albeit lower, between Broome and Fitzroy Crossing, and Broome and Derby. These tracks also place the aircraft in direct conflict with Broome Runway 28 Instrument Approach Procedure (IAP) waypoints which is especially of concern in the wet season.
For those VFR aircraft in Class E this is in direct contradiction to ENR 1.1 - 3.2 and those operating above 5,000 ft AMSL in Class G are contravening ENR 1.4- 4.1 whilst limiting the usefulness of IFR aircraft radio calls required by ENR 9.9 (refer below).
Aeronautical Information Publication (AIP) Australia
ENR 1.1- 3.2 VFR Flights in Class E Airspace
3.2.1 VFR flights entering Class E airspace do not require a clearance, but mat may receive a Surveillance Information Service (SIS), where available, on request (see GEN 3.3 section 3.3).
3.2.2 VFR flights entering and operating in Class E airspace should:
a. avoid published IFR routes, where possible;
b. monitor the appropriate Class E frequency and announce if in potential conflict; and
c. take appropriate action to avoid potential conflict.
3.2.3 Pilots of VFR fights should avoid IFR holding patterns.
9.9 Descent from Controlled Airspace
9.9.1 Before descending from controlled into Class G airspace and before separation with any aircraft operating near the base of controlled airspace can be compromised, the pilot in command of an IFR flight must report position, level, intentions and estimate for next position/destination to the Air Traffic Service (ATS) unit providing services in Class G airspace. If the report is made using High Frequency (HF) radio, a broadcast must be made on the appropriate Very High Frequency (VHF) frequency.
The reporter understands the concerns of the operators which is not to block up the area frequency to facilitate their separation, however this cannot take precedence over the AIP rules and if it does start to clog up the area frequency then the need for a separate frequency will have to be looked at like occurs in the North and East Kimberley (which we will monitor and broadcast on).
The reporter believes an education session by CASA is required to address this as past attempts to bring up these issues with the operators directly have been unsuccessful.
CASA recognises the critical importance of understanding airspace user experiences to ensure the safety, efficiency, equitable access, and continuous improvement of the Australian airspace system. The use of the REPCON scheme to raise concerns about user experiences severely limits the ability of CASA to explore those concerns, as such we encourage the reporter to contact CASA directly.
Please see the regulator (CASA) response above.