Instructions

Overview

Airborne Radar Approach is a tactical display for planning and flying an airborne radar approach to an offshore installation or vessel. It shows your destination, the final approach track (FAT), the clear approach track template, live AIS traffic, and a vertical profile with stepped descent gates.

The app is best experienced when opened as a standalone app on an iPad or iPhone. To install it, open the site in Safari, press the Share button and select Add to Home Screen. Launching from the home screen icon gives a full-screen layout without the browser chrome.

1. Set the destination

In the top bar there are two ways to set a destination:

• Destination (lat / lon) — type coordinates directly, e.g. 60 07.40N 005 25.92E. Press Enter or tab out to commit.
• ICAO lookup — type a 4-letter ICAO code for a known fixed installation or helideck vessel. The position (and magnetic variation for fixed sites) is filled in automatically. For vessels the live AIS position is used.

If you enter raw coordinates, magnetic variation is taken from the nearest fixed installation that has a known value. The source is shown next to the VAR label.

2. Final Approach Track (FAT)

Enter the final approach track in degrees magnetic (1–360°). This is the inbound track to the destination on which the clear approach track template, IAF/FAP/OIP gates, and missed approach geometry are anchored. Arrow up/down step the value by 1°.

3. Minimas

• Minima (ft) — minimum descent altitude, in feet. Used as the lower gate in the vertical profile.
• Minima (nm) — minimum descent distance to the destination, in nautical miles. Accepts decimals (e.g. 0.75 or 0,75).

4. Missed approach

Pick Left or Right to set the missed approach turn direction. The map overlay and the clear approach track template mirror accordingly.

5. Templates and clear sectors

The active clear approach track template is selected in Settings. CHC HS is the default; LT is the same logic but with the FAP at 4 nm.

Clear tracks for each installation can be found in the information panel for that destination — open the info box on the map to read the published clear sectors before committing to a FAT.

6. Working with traffic

All AIS targets shown on the map are clickable. Selecting a target allows you to set it as your new destination — useful when you need to plan for a nearby target, for example diverting to a vessel or installation close to your current destination.

Magnetic variation for the new destination is taken from the nearest fixed installation that has a known value. The source is shown next to the VAR label in the top bar.

7. Map symbols and colour coding

Each target type on the map has a distinct colour so you can tell at a glance what you are looking at and how trustworthy the position is.

• Blue — Fixed installation. Platform or rig with an ICAO code and a fixed, surveyed position. Magnetic variation is taken from this record when used as a destination.
• Pink — Helideck vessel (known). Known helideck vessel with an ICAO code. Position is not fixed — it is updated live from AIS. Pink regardless of fix age so the helideck fleet is always recognisable.
• Green / Orange — Other AIS vessel. Any AIS target that is not a known helideck vessel. Green when the last AIS fix is within the past 5 minutes, orange when older than 5 minutes. The last fix time is shown in the info box when the target is selected.
• Yellow — Fixed obstacle. Charted offshore obstacle. Always yellow — position is fixed and does not rely on AIS.

8. SAR — Search and Rescue

The SAR button (top bar, left of Instructions) opens a dedicated page for locating a vessel by name via live AIS and exporting useful content to ForeFlight.

Start typing a vessel name; matching vessels are listed below the input with bearing and distance from your current position. Press USE on a match to set it as the current approach destination.

• USE also downloads a ForeFlight Custom Content Pack containing the single rescue point — a map layer with a red circle at the vessel position and a user waypoint named RSQPT. Load the pack in ForeFlight and route directly to RSQPT.
• Download rig-pack (button at the top of the SAR page) builds a full ForeFlight Custom Content Pack covering all known fixed installations, moored and moving rigs/ships (with live AIS positions where available) and charted offshore obstacles. Install it in ForeFlight to see the complete offshore picture on the map.

AIS data

AIS (Automatic Identification System) is a maritime tracking system where vessels broadcast identity, position, course and speed over VHF. Coastal receivers aggregate these messages, and this app displays the resulting live picture of traffic around your destination so you can spot conflicts and identify helideck vessels.

SAR aircraft (MMSI starting with 1) are filtered out of the display.

The vector line extending from each AIS target shows the expected position one hour ahead, based on its current course and speed.

AIS data and API are provided by BarentsWatch. Credit and thanks to BarentsWatch for making the feed available.

iPad GPS accuracy

The iPad's internal GNSS receiver typically delivers a horizontal position accuracy of around 3–10 metres in clear sky, which is displayed as the H ± value in the strip below the map.

Vertical accuracy is always worse than horizontal, typically by a factor of 2–3×. This is a geometric property of GNSS: satellites are only visible above the horizon, so the vertical dilution of precision (VDOP) is structurally higher than the horizontal one (HDOP). Expect vertical accuracy in the order of 30–100 feet even when horizontal accuracy looks excellent.

The iPad's own estimate of the vertical accuracy is shown as the V ± value (in feet) in the strip below the map. Note that the reported altitude is ellipsoidal (WGS-84 height above the reference ellipsoid), not barometric and not height above mean sea level. The bias between WGS-84 and MSL alone can be on the order of a hundred feet depending on geographic location.

Operational use: trust the horizontal GPS position for situational awareness and lateral navigation, but never use GPS altitude as a primary vertical reference against minima.

Contact

Found a problem, experienced an error, want to add a clear approach track template, or need to report a missing fixed obstacle? Send an email to mikael.botnen@swedishairservice.se.