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Oceanic flights are some of the most rewarding experiences on VATSIM, but they require additional preparation and knowledge. When you cross an ocean, you leave the world of continuous radar coverage and enter airspace where aircraft are separated by time, altitude, and precise routing. This guide covers everything you need to know for a successful oceanic crossing.
Oceanic flights require additional preparation compared to domestic routes. Read this guide thoroughly before attempting your first oceanic crossing. Being unprepared in oceanic airspace can disrupt the flow for controllers managing dozens of transatlantic flights simultaneously.

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What Are Oceanic Procedures

Over the ocean, there are no radar stations. ATC cannot see your aircraft on a radar scope the way they can over land. Instead, separation between aircraft is maintained through:
  • Assigned tracks (specific routes across the ocean)
  • Assigned flight levels (altitude separation)
  • Assigned Mach numbers (speed separation - all aircraft on the same track fly the same speed)
  • Position reports (pilots report their location at each waypoint)
This is called procedural control rather than radar control. It requires precision and discipline from pilots.

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NAT Tracks (North Atlantic Tracks)

The North Atlantic Track System (NAT) is an organized set of routes between North America and Europe. These tracks are published daily and change based on winds and traffic demand.

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How NAT Tracks Work

  • Eastbound tracks are published daily for nighttime crossings (departing North America in the evening, arriving Europe in the morning)
  • Westbound tracks are published daily for daytime crossings (departing Europe in the morning, arriving North America in the afternoon)
  • Each track is identified by a letter (Track Alpha, Track Bravo, Track Charlie, etc.)
  • Tracks are positioned to take advantage of favorable winds (tailwinds eastbound, avoiding headwinds westbound)

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Finding Current NAT Tracks

  • SimBrief automatically includes the current NAT tracks when you generate an oceanic flight plan
  • NAT Track messages are published by Gander and Shanwick and can be found on various aviation websites
  • VATSIM tools like SimAware show active tracks during events
When planning an oceanic flight, use SimBrief and let it select the optimal track for you. It considers current winds, your aircraft type, and preferred flight level to recommend the best route.

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NAT Track Structure

A typical NAT track consists of:
  1. Oceanic entry point - a waypoint on the North American or European coastline (e.g., DOTTY, ALLRY, ELSIR)
  2. Oceanic waypoints - intermediate points across the ocean, defined by latitude/longitude coordinates
  3. Oceanic exit point - a waypoint on the opposite coastline
Your full route includes domestic segments on each side connecting your departure and arrival airports to the oceanic entry and exit points.

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Oceanic Control Stations

Several ATC facilities manage oceanic airspace across the North Atlantic:
StationICAO CodeAirspace Coverage
Gander OceanicCZQXWestern North Atlantic (Canadian side)
Shanwick OceanicEGGXEastern North Atlantic (European side)
New York OceanicKZWYSouthern North Atlantic routes
Santa Maria OceanicLPPOSouthernmost Atlantic routes (Azores region)
Reykjavik OceanicBIRDNorthern Atlantic routes (Iceland region)
On VATSIM, these stations are staffed by volunteers and may not always be online. During major events like Cross the Pond (CTP), you can expect full oceanic coverage. At other times, you may cross the ocean on UNICOM.

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Step-by-Step Oceanic Flight

1

Plan your route

Use SimBrief to generate your flight plan. It will automatically include:
  • The optimal NAT track for your direction and time of day
  • Oceanic entry and exit points
  • Appropriate flight level based on your aircraft and direction of flight
  • Estimated time for each oceanic waypoint
Include your SELCAL code in the remarks field if you have one (format: SEL/ABCD).
2

File your flight plan

File your flight plan on VATSIM well before your departure. For events, file at least 2-3 hours early. Your route should include the full NAT track waypoints.
3

Fly the domestic segment

Depart and fly normally through domestic airspace, communicating with Delivery, Ground, Tower, Departure, and Center as usual.
4

Request oceanic clearance

30 to 40 minutes before reaching the oceanic boundary, request your oceanic clearance from the appropriate oceanic station. This gives ATC time to coordinate your entry into the track system.You can request clearance by voice or CPDLC (if supported).
5

Enter oceanic airspace

At your oceanic entry point, you must be:
  • At your cleared flight level
  • On your assigned track
  • At your assigned Mach number
  • With your transponder on and squawking the assigned code
6

Report position at each waypoint

As you cross each oceanic waypoint, report your position to ATC (by voice or CPDLC). Include your time over the waypoint, flight level, next waypoint, and estimated time at the next waypoint.
7

Exit oceanic airspace

At your oceanic exit point, the oceanic controller will hand you off to the domestic ATC facility on the other side (e.g., Shanwick hands you to Scottish Control, or Gander hands you to Moncton Center).
8

Continue to destination

Resume normal domestic ATC communication for the remainder of your flight.

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Oceanic Clearance

Before entering oceanic airspace, you must receive an oceanic clearance. This is separate from your original IFR clearance and specifies exactly how you will cross the ocean.

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Requesting Clearance by Voice

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What the Clearance Contains

ElementDescription
Clearance limitYour destination airport
TrackThe assigned NAT track (may differ from what you filed)
Flight levelYour assigned cruise altitude for the oceanic crossing
Mach numberYour assigned cruise speed
Entry pointThe waypoint where you enter oceanic airspace
Entry requirementsAltitude and time requirements at the entry point
ATC may assign you a different track or flight level than what you filed. You must comply with the clearance as given. If the assigned flight level or Mach number is outside your aircraft’s capabilities, respond with “Unable” and state the reason.

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Position Reporting

In oceanic airspace, position reports replace radar as the primary means of separation. Reports must be accurate and timely.

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Position Report Format

Each report includes:
  1. Position - the waypoint you are at or have just passed
  2. Time - UTC time you crossed the waypoint
  3. Flight level - your current altitude
  4. Next waypoint - the next point on your route
  5. ETA - estimated time of arrival at the next waypoint
  6. Following waypoint - the waypoint after the next one
Use Hoppie CPDLC for oceanic position reports when available. It is faster, less error-prone, and reduces congestion on the voice frequency. See the SELCAL and CPDLC page for setup instructions.

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Mach Number Technique

In oceanic airspace, all aircraft on the same track at the same flight level fly the same Mach number. This is called the Mach Number Technique and it ensures consistent spacing between aircraft.

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How It Works

  • ATC assigns you a specific Mach number in your oceanic clearance (e.g., Mach 0.82)
  • You must maintain this exact Mach number throughout the oceanic crossing
  • Do not speed up or slow down without ATC approval
  • If you cannot maintain the assigned Mach number (e.g., due to turbulence or aircraft performance), notify ATC immediately

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Requesting a Mach Number Change

Changing your Mach number without clearance in oceanic airspace is a serious issue. It affects separation with aircraft ahead of and behind you on the same track. Always get approval before changing speed.

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SLOP - Strategic Lateral Offset Procedures

SLOP is a safety procedure that allows aircraft to fly slightly off the track centerline to reduce the risk of collision due to navigational errors.

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How SLOP Works

  • You may offset 1 nautical mile or 2 nautical miles to the right of the track centerline
  • You may also fly on the track centerline (no offset)
  • Never offset to the left - this puts you closer to traffic on adjacent tracks
  • No ATC clearance is required to use SLOP
  • You do not need to report your offset to ATC

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Applying SLOP

Most modern FMS systems have a lateral offset feature. Set it to 1R or 2R (1 or 2 nautical miles right) before entering oceanic airspace.
SLOP is optional but recommended. Most real-world airlines require their crews to use a 1 or 2 nautical mile right offset on all oceanic crossings.

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Oceanic Flight Planning Tips

Eastbound flights use odd flight levels (FL350, FL370, FL390) and westbound flights use even flight levels (FL340, FL360, FL380) under RVSM rules in the North Atlantic. SimBrief will suggest an appropriate flight level based on direction and aircraft performance.
NAT tracks are valid for specific time windows. If you depart too early or too late, the tracks may not be active. SimBrief accounts for this when generating your flight plan.
Outside NAT track hours, or if your route does not align with published tracks, you may fly a random route across the ocean. These are defined by latitude/longitude waypoints and must be filed and cleared like any other oceanic route.
Oceanic ATC is most commonly staffed during Cross the Pond (CTP) events and other organized transatlantic events. If you want the full oceanic experience with live ATC, plan your crossing during one of these events.
Know what to do if you cannot maintain your assigned flight level or Mach number. Have alternate flight levels in mind and be ready to communicate any issues to ATC promptly.

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Next Steps

SELCAL and CPDLC

Set up SELCAL and Hoppie CPDLC for oceanic datalink communications

Special Events

Learn about Cross the Pond and other major VATSIM events