Flying in Oceanic Airspace

What's the difference between normal ATC, and Oceanic ATC?

Normal ATC throughout Australia (Brisbane Centre, Melbourne Centre, Sydney Approach, etc.) rely on radar to determine where an aircraft is in the air. This could be through ADS-B, MLAT, or good ol' SSR.

Over the ocean, it's not as easy to place a radar down and hope that it doesn't float away... Therefore, there is no radar. This non-radar airspace is controlled by oceanic ATC.

In short, normal ATC has radar and covers over land (Sometimes referred to as Domestic ATC). Oceanic ATC, doesn't have radar and rely on other methods to depict where aircraft are in the world.

 

Where does Oceanic ATC cover?

In Australia, the OCA (Oceanic Control Area) is where all oceanic ATC takes place. This area is covered by multiple sectors:

In the Brisbane FIR (YBBB), we have BN-TSN_FSS (Tasman) covering the Tasman Sea up to the Coral Sea:

This during special events, this standard sector splits further into BN-COL_FSS (Coral) covering the northern part of the Coral Sea, BN-FLD_FSS (Flinders) covering the southern part of the Coral Sea, and BN-HWE_FSS (Howe) covering the Lord Howe Island area (Which is equipped with ADS-B, will touch on later)

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In the Melbourne FIR (YMMM), we have ML-IND_FSS (Indian) covering the Indian ocean and all south of Australia down to Antarctica:

This during special events, this standard sector splits further into ML-INE_FSS (Indian East) covering the north west of Port Headland and Karratha, up to the southern part of Jakarta, and ML-INS_FSS (Indian South) covering south of Australia down to Antarctica.

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Now that we know where they are, how do you communicate to Oceanic ATC:

First things first; The all OCAs in Australia are controlled from Brisbane, so all oceanic controllers in Australia are called "Brisbane Radio", there is no "Melbourne Radio", so yes, ML-INx_FSS is called "Brisbane Radio".

Now that that's out of the way, let's get down to business.

When domestic ATC hands you off to an Oceanic controller, the handoff will sound similar to this:

BN-MDE_CTR: "Qantas 151, crossing PLUGA, identification terminated, report your position to Brisbane Radio on 128.6, g'day"

Or, if you are using CPDLC:

BN-MDE_CTR: "Qantas 151, continue with Brisbane on Datalink, monitor VHF primary 128.6, g'day"

So what does this mean?:

"Crossing PLUGA, identification terminated": Once you're overhead the waypoint "PLUGA", you are no longer within range of radar, and we can no longer identify you.

"Report your position to Brisbane Radio on 128.6": Once you're overhead the waypoint "PLUGA", provide Brisbane Radio with a position report on frequency 128.6.

"Continue with Brisbane on Datalink": Remain in CPDLC contact with Brisbane (YBBB) and do not log off.

"Monitor VHF primary 128.6, g'day": Monitor frequency 128.6, you are not required to transmit any position reports.

 

Now, communicating to oceanic:

When making initial contact:

QFA151: "Brisbane Radio, Brisbane Radio, Qantas 151 with position." Note: It is good practice to state the callsign of the station you are calling twice.

At this point, Brisbane Radio will respond in one of two ways:

BN-TSN_FSS: "Qantas 151?" Note: When a controller says your callsign alone, it's either an acknowledgement of a previous transmission or an indication for you to go ahead. In this case, it's "Go ahead."

Or

BN-TSN_FSS: "Qantas 151 Brisbane accepts primary guard this frequency. Secondary 122.1, standby for a SELCAL check" 

So what does this mean?:

"Brisbane accepts primary guard this frequency": This frequency can be used in place of the standard guard frequency, 121.500.

"Secondary 122.1": If you are unable to reach me on this frequency, then try again on 122.1.

"Standby for a SELCAL check": Please wait before transmitting, I am about to test your SELCAL system.

 

If your SELCAL check is okay, meaning you have received the SELCAL alert, then you should respond with:

QFA151: "Brisbane Radio, Qantas 151 SELCAL check okay."  Meaning you have received the SELCAL alert.

After this point, Brisbane Radio should be ready for a position report:

BN-TSN_FSS: "Qantas 151, go ahead with position."

Now for the hard part, the position report...

 

What are position reports?

Position reports are how ATC can determine where you are. Position reports contain estimates for waypoints, speeds, altitudes and any other information. Because there is no radar over the ocean, ATC relies on time-based separation and reports from the pilots. ATC has no way of determining where you are unless you specifically tell them.

The standard format is:

Current/Previous waypoint name and the time which you crossed that point.

Current flight level.

Mach number if assigned by ATC.

Your next waypoint and estimate for that point.

The waypoint after that.

VATPAC provides a nice tool for pilots to help put together position reports: https://vatpac.org/pilots/pilot-tools/oceanic-reporting-tool/

 

Let's look at some examples:

Example 1:

QFA151 (Qantas 151) from Sydney to Wellington enters oceanic airspace at waypoint PLUGA. Not using CPDLC and equipped with a SELCAL code of CP-RS.

BN-MDE_CTR: "Qantas 151, Crossing PLUGA, identification terminated, report your position to Brisbane Radio on VHF 128.6, g'day"

QFA151: "Report position to Brisbane Radio on 128.6, Qantas 151, g'day"

QFA151 tunes to 128.6

QFA151: "Brisbane Radio, Brisbane Radio, Qantas 151 with position."

BN-TSN_FSS: "Qantas 151 g'day, Brisbane accepts primary guard this frequency. Secondary 122.1, standby for a SELCAL check" 

Brisbane Radio broadcasts the CP-RS SELCAL code over the frequency.

QFA151s radio alerts the pilot that a SELCAL was received.

QFA151: "SELCAL check okay, Qantas 151."

BN-TSN_FSS: "Qantas 151 go ahead with position?" 

QFA151: "Qantas 151 is position PLUGA at time 0627, flight level 380, estimating VELKU at 0655, SASRO next."

BN-TSN_FSS: "Qantas 151." Note: Unlike other FIRs, Australian ATC (YMMM and YBBB) are not required to read back your position report.

Qantas 151 will continue to provide position reports each time they reach a new point along the route until back within radar coverage and identified.

Brisbane Radio can use your position report to build an image of where you are. The image below is from BN-TSN, the circles are aircraft identified on Mode-C, and the boxes are approximate positions based on the pilots' position reports:

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Example 2:

QFA151 (Qantas 151) from Sydney to Wellington enters oceanic airspace at waypoint PLUGA. Using CPDLC and equipped with a SELCAL code of CP-RS.

BN-MDE_CTR: "Qantas 151, continue with Brisbane on Datalink. Monitor VHF primary 128.6"

QFA151: "Continue with Brisbane on Datalink, monitor 128.6, Qantas 151, g'day"

QFA151 tunes to 128.6 and monitors that frequency.

QFA151 and YBBB remain in contact through CPDLC and ATC can obtain automatic position reports through CPDLC. The pilots must monitor the frequency for SELCAL alerts and are not required to provide position reports through voice.

Brisbane Radio can now use CPDLC/ADS-C to retrieve your position through ACARS. Triangles are aircraft whose position is sent through CPDLC using ADS-C:

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Example 3:

QFA151 (Qantas 151) from Sydney to Wellington has entered oceanic and is requesting a step climb to FL400.

QFA151: "Brisbane Radio, Brisbane Radio, Qantas 151."

BN-TSN_FSS: "Qantas 151?"

QFA151: "Brisbane Radio, Qantas 151, request climb to FL400"

BN-TSN_FSS: "Qantas 151 climb to FL400, requirement to reach FL400 by VELKU, report reaching." Note: QFA151 must reach FL400 at or before VELKU. This prevents conflicts when in the middle of an altitude change over a point. They are also asked to report reaching FL400, so ATC can determine when they are level at FL400

QFA151: "climb to FL400, requirement to reach FL400 by VELKU, will report reaching, Qantas 151"

QFA151 reaches FL400.

QFA151: "Brisbane Radio, Brisbane Radio, Qantas 151."

BN-TSN_FSS: "Qantas 151?"

QFA151: "Brisbane Radio, Qantas 151, reaching FL400"

BN-TSN_FSS: "Qantas 151."

 

Example 4:

BN-TSN_FSS detects a conflict between QFA151 (Qantas 151) and ANZ132 (New Zeland 132). QFA151 is using CPDLC, ANZ132 is not and is using the SELCAL code FS-CH.

Brisbane Radio broadcasts the FS-CH SELCAL code over the frequency.

ANZ132s radio alerts the pilot that a SELCAL was received.

ANZ132: "Brisbane Radio, New Zeland 132 answering SELCAL."

BN-TSN_FSS: "New Zeland 132 climb to reach non-standard FL360 by VELKU, report reaching."

ANZ132: "Climb to reach non-standard FL360 by VELKU, will report reaching, New Zeland 132"

Or:

Brisbane Radio sends a message QFA151 via CPDLC, telling the pilots to descend to FL350 and report when reaching.

QFA151 receive and acknowledge the message on their FMC. They then begin their descent.

Once QFA151 have reached FL350, they send a message to Brisbane Radio via CPDLC stating they have reached FL350.

 

How can I help ATC when flying?

  1. Fly with the correct UTC time set in your simulator. Since ATC rely on your estimates, they must be in the correct UTC time. Before connecting to VATSIM, make sure your time of day and your aircrafts UTC clock are set to the correct UTC time. You can find the current UTC time on Google, vPilot (Flight plan window), or even on your phone's clock!
  2. Prepare your position reports beforehand. Before you cross your next position, have your position report ready and prepare to give it to ATC. You can use VATPACs oceanic tool (https://vatpac.org/pilots/pilot-tools/oceanic-reporting-tool/), or if you're flying Boeing, you can go to your FMCs PROGress page, and then to the POS REP page.
  3. Use CPDLC. CPDLC (Controller Pilot DataLink Communication) is a form of communication between pilots and controllers which uses ACARS and satellite data. ATC can use CPDLC to issue instructions through the onboard flight computers. The messages are in plain text and are easier to read than a radio transmission. It can be much easier to manage than a cluttered frequency and can save time when making requests to ATC both domestic and oceanic. VATSIM doesn't support CPDLC natively, but the VATPAC TAAATS simulation supports the Hoppie ACARS/CPDLC system. The pilot client can be found here: http://www.hoppie.nl/acars/prg/air/
  4. Find your SELCAL code. Each aircraft has a unique SELCAL (Selective Calling) code assigned to it. SELCAL is used to "Ping" a pilot when ATC needs them, so they the pilots don't have to listen to the poor quality of the radio throughout their oceanic crossing, they can just wait for the SELCAL alert from ATC, then start paying attention to the radio. You can use http://www.airframes.org/ to find the SELCAL code for your aircraft. You can enter your SELCAL code when connecting using vPilot, or if you're using X-Plane, you can use xSelcal: https://forums.x-plane.org/index.php?/files/file/35528-xselcal/
  5. Make sure ATC is ready for your position report. When providing a position report, make sure ATC is ready by saying  "Brisbane Radio, Brisbane Radio, Qantas 151 with position." then wait for Brisbane Radio to give you the go-ahead for the report. This makes sure Brisbane Radio is ready to take the report.
  6. Tell ATC when your ETAs update by more than 2 minutes. If your ETA changes by more than 2 minutes from the time you told ATC with your position report, you must provide ATC with a "Revised Estimate". Eg:

QFA151: "Brisbane Radio, Brisbane Radio, Qantas 151."

BN-MDE_CTR: "Qantas 151?"

QFA151: "Brisbane Radio, Qantas 151, revised estimate for VELKU 0502z"

BN-MDE_CTR: "Qantas 151."

 

Identification near Lord Howe Island (LHI):

Lord Howe Island has an ADS-B receiver based on the Island. This means that any aircraft within range can be identified, and are not required to pass position reports. ATC will indicate this by telling you whether or not you are identified.

The grey circle around Lord Howe Island is the ADS-B range of the receiver.

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When BN-HWE_FSS ("Brisbane Radio", Howe), they will cover most of this area.

 

Non-radar in Domestic Airspace:

The BN-TRT_CTR sector (Territory), BN-ARA_CTR sector (Arafura) and BN-KIY_CTR sub-sector (Kimberly) lack radar coverage in their northern areas towards the WAAF FIR (Ujung Control). This results in a control service similar to Oceanic ATC, however, there are no SELCAL checks or procedures, secondary frequencies, or guard override frequencies. The red line depicts where radar coverage may be lost/regained:

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CPDLC can still be used and the controller callsign will remain as "Brisbane Centre".

 

More info:

CPDLC: Controller Pilot DataLink Communication: A text-based communication system between pilots and ATC utilising ACARS. Typically accessed through the MCDU/DCDU or MFD.

https://en.wikipedia.org/wiki/Controller–pilot_data_link_communications

ADS-B: Automatic Dependent Surveillance-Broadcast: Highly accurate radar data containing much more information than standard Mode C transponders.

http://www.airservicesaustralia.com/projects/ads-b/how-ads-b-works/

ADS-C: Automatic Dependent Surveillance-Contract: A CPDLC position reporting system set up by ATC. Sends aircraft position and altitude details to ATC depending on their requirements.

https://www.skybrary.aero/index.php/Automatic_Dependent_Surveillance_-_Contract_(ADS-C)

SELCAL:  Selective Calling: A unique tone assigned to each aircraft, which when broadcast over the currently tuned radio frequency, will alert the pilots.

https://en.wikipedia.org/wiki/SELCAL

Radar images from EuroScope/TAAATS and AccuMap-Project .

 

Thanks to Eoin Motherway for this detailed tutorial.