Due to it's remoteness from the rest of the world, a high percentage of flights in New Zealand airspace travel in Oceanic Airspace. This FAQ will outline what to do when flying in Oceanic Airspace.
Oceanic Flight Information Regions
The oceanic area in VATSIM Oceania Region is split up into six different regions as depicted:
Entering & Leaving Oceanic Airspace
Entry into Oceanic Controlled Airspace (OCA) is usually occurs at around 150-200nm from the coast, depending on the centre/approach controller's requirements. Inbound aircraft are usually handed off no later than 150nm from the coast, however this is again at the controller's discretion.
Unless otherwise indicated or instructed, maximum speed below 10,000ft is 250 KIAS.
All Oceanic FIRs: Transponder should squawk last assigned code, or code 2000 if none assigned.
RVSM (Reduced Vertical Separation Minima)
All Brisbane, Auckland, Tahiti and Nadi oceanic airspace has been designated RVSM (Reduced Vertical Separation Minima) airspace, with new aircraft cruising levels as shown in the images below. Aircraft capable of RVSM are to note this capability in their flightplan. Vertical separation between two RVSM-equipped aircraft is 1000ft, however should only one or none of the aircraft have RVSM capability, 2000ft should still be used. Lateral separation remains unaffected. See image below for table of RVSM cruising levels. Pilots should be aware of the need to re-plan their cruise levels should they transition between RVSM and non-RVSM airspace.
Subject to traffic, the controller may issue an aircraft with a Block Clearance between two flight levels. When this is issued, the aircraft may operate at any altitude between the two levels, even if it is not a standard flight level (e.g. FL347 for a block clearance between FL310 and FL370). During the position reports, the pilot must announce that he is "In the block between FLxxx and Flxxx," but the exact level at which he/she is flying need not be reported.
The controller must ensure that there is a minimum longitudinal (horizontal) separation of 15 minutes or more between aircraft on the same or crossing tracks, as well as a minimum of 2,000ft vertical separation. Horizontal separation can be obtained by ensuring that, in the case of two aircraft flying the same track in the same direction and level, the first aircraft's estimate for the NEXT common position is at least 15 minutes earlier than the following aircraft's estimate for that same position. If a discrepancy is found it is up to the controller to either ask for a level change or to impose a mach number restriction on the following aircraft.
Most aircraft you will see in the VATNZ region will be Australian or New Zealand Registered:
- New Zealand: ZK- prefix e.g. ZKDEF
- Australia: VH- prefix, e.g. VHABC
(note there is no hyphen in the ATC Callsign)
Alternatively, Flight Number Callsigns (FNCs) will be used. They consist of the airline's two letter designator, followed by the flight number. Here are some examples which you are likely to find in the VATPAC region.
- VIRGIN AUSTRALIA: VOZ - e.g. VOZ83 - Virgin Australia Flight 83 (Voice - Velocity 83).
- QANTAS: QFA - e.g. QFA100 = Qantas Flight 100 (Voice - Qantas 100).
- AIR NEW ZEALAND : ANZ - e.g. ANZ123 = Air New Zealand Flight 123 (Voice - New Zealand 123).
- EMIRATES: UAE - e.g. UAE406 = Emirates Flight 406 (Voice Emirates 406)
Oceanic Air Traffic Control Procedures
Oceanic Air Traffic Control is essentially quite simple. At each waypoint along the aircraft's track, the pilot makes a position report to the oceanic centre giving his time over the waypoint, the estimated time over the next waypoint, and the name of the waypoint after that. He will also give his mach number, groundspeed, wind and temperature details, though the weather details are optional in some cases (they are not required for VATPAC ops). The following is a sample position report.
Pilot: Auckland Radio, New Zealand 83 position on 128.9
(New Zealand 83 is calling Auckland on frequency 128.6 to give his report)
ATC: New Zealand 83, Auckland, go ahead.
Pilot: New Zealand 83 is position ANULI at time zero two, Flight Level 350, estimating VIROG at four two, IGEVO next. Mach decimal 84, groundspeed 510. Wind 160 diagonal 15, temperature minus 25. Go ahead.
(New Zealand 83 is at position ANULI at time 1002 (UTC) at FL350. He will pass position VIROG at 1042 (UTC) and the next position after that is IGEVO. He is flying at Mach .84, and his groundspeed is 510 knots. The wind at his position is 160 degrees at 15 knots and the temperature is -25 degrees Celsius)
ATC: New Zealand 83 roger Auckland.
SELCAL on VATSIM
When ATC wishes to communicate with an aircraft, they will send a single SELCAL message to the flight. All aircraft monitoring that channel receive the SELCAL broadcast, which consists of two tones, but only the intended recipient will hear the "Ding Dong" of an incoming message. When alerted by SELCAL, the crew then turn up their radio to communicate with ATC. The crew must then ensure that the message is intended for them, responding using ICAO recommended radio procedures.