Limitations

By design there is only so much LiveTraffic can achieve

The Basis is Live Flight Tracking Data

The prime principle of LiveTraffic is: LiveTraffic puts a plane where external tracking data demands it to be. Tracking data provides a position with a timestamp, about every 10-30 seconds per plane. LiveTraffic makes sure that at that reported point in time the plane is exactly at that reported position. Inbetween any two tracking data points, LiveTraffic needs to interpolate data at its own discretion. Eventually, LiveTraffic recalculates a plane's position with every drawing frame of X-Plane, ie. several dozen times per second!

The tracking data received from the channels, however, ...

• can and will be inaccurate,

• never includes all planes in the air,

• is geographically restricted to the coverage the channels provide,

• often misses moving planes on the ground as ADS-B receiver coverage is more difficult the lower a plane flies,

• provides by design only positional data every few seconds but no reliable paths or vectors,

• does not include situational or configuration info (pitch, roll; gear, flaps, ...).

Check your coverage first

• OpenSky Network Explorer

• ADS-B Exchange Global Radar

• The RealTraffic app provides an integrated radar view, see here for an example

You will at maximum see the same aircraft as show on their pages. Quite some big US airports have comparably bad data coverage, e.g. KSFO, KATL, KLGA, even KJFK.

Ground coverage is very much limited by the fact that the earth is round and ADS-B signals travel like all radio signals do: like a straight line: The radio signals an aircraft on the ground sends out can only be received by ground-based receives, which are very close to the aircraft, ie. very near to the airport. The signals cannot be received by receives behind the horizon or behind countless obstacles like buildings or forests. Good ground coverage requires that somebody operates an ADS-B receiver close to the airport.

Implications on simulated aircraft

The data inaccuracy inevitably leads to some aircraft

• not sticking exactly to taxi routes on the ground,

• touching down before or after the beginning of the runway,

• disappearing after roll-out (see autoland...it's actually a feature to prevent them from disappearing even earlier during approach, LiveTraffic will never simulate taxiing to the gate without having proper tracking data),

• missing the runway by a few meters or even landing off-site,

• appearing and disappearing at will,

• performing funny maneuvers like full circles or flying extremely slow,

• missing from the scenery due to limited coverage, which most often happens to exactly those flights you'd really really like to follow.

Also, there will be (next to) no parking aircraft at the gates as transponders are usually switched off by that time and aircraft are no longer trackable.

There is an awful lot of data cleansing and take off / landing prediction in LiveTraffic, which tries try smoothing all of these effects, and we'll keep working on it...but it only works so far. In general, OpenSky seems to be a bit more accurate than ADS-B-Exchange.

As of now, LiveTraffic takes the following ground features into account:

• Ground altitude is always considered as per scenery.

• Runway detection for auto land is in as per v1.24.

• Sinve v1.5, LiveTraffic also reads and uses taxiway and gate/ramp information (see here)

I will not follow up on issues like "I once saw an aircraft that...".

If you find a pattern, though, like "Many planes around KXYZ, especially in the evening, tend to blablabla", then you would have time to switch log level to Debug, activate position logging, maybe even network raw data logging, and shoot some meaningful screenshot including an a/c info window, see Tips on Testing. And then I can follow up.

There is a small time lag between reality and LiveTraffic's aircraft display.

For the above mentioned processing LiveTraffic needs data. The more it is allowed to "look into the future" the better it is able to smoothen especially take off and landing. This buffering period, which is equivalent to the time lag as compared to reality, is configurable in the Advanced Settings and defaults to 90 seconds. There is an FAQ for more background on why buffering is needed.

There is no sound coming from LiveTraffic planes.

All you hear is your own engines. As sound support is very high effort both in implementation and in getting open source sound samples, sound is not a functionality to come anytime soon.

Live aircraft will ignore your own plane.

Live aircraft will be where reality puts them regardless of your plane's position. They simply fly or drive through you if you are in the way. That can look funny if you are stopping short at the beginning of the active departure runway and a A380 performs its take-off roll through you.

You may, however, impersonate an existing plane and take over its queue position!

There can be only one Multiplayer client

The Highlander issue: LiveTraffic is a multiplayer client like XSquawkBox, X-IvAp, Swift, or PilotEdge are as well. All of them want to take control of the so-called multiplayer aircraft, also known as AI aircraft. These are the up to 19 additional aircraft X-Plane offers as a standard feature. They are not needed for drawing planes into the sky, but they are needed to create blibs on TCAS screens (see Installation/X-Plane Setting).

If multiple of those multiplayer clients are active only the first one will get access to the multiplayer planes and controls what is seen on TCAS displays, the others fail. X-Plane starts up plugins in alphabetical order of folder name...the first one wins.

Users of multiple clients are long used to moving plugins in and out of the plugins folder, e.g. to a plugins_decatived folder, before starting X-Plane. LiveTraffic tries to play nice (see notes on parallel operation) but has no control over how other clients behave. And they often acquire access to the multiplayer planes but never release them if not deactivated the hard way in the plugin admin.

Other Limitations

TCAS display implementations in add-on planes vary and are beyond my control. LiveTraffic uses the same underlying library to display additional aircraft as XSquawkBox does. If there are issues with XSquawkBox or X-IvAp the same will apply to LiveTraffic. However, I received much positive feedback, so chances aren't too bad.

You can't talk to real life air traffic control.

Just saying...you might be able to listen in some areas using services like Live ATC, but no chance to interact. It means that if you intend to line up with the chain of aircraft approaching a busy runway you have to find and maintain your spot yourself. Same goes for take off. Good luck!

LiveTraffic's flight modelling doesn't yet work for helicopters, baloons, or the like.

It is optimized for commercial jet and turbo prop planes. Should be OK for GA aircraft, might work for other fixed-wing aircraft, but will definitely fail for other types. Other types will still apear in the sky (their representation certainly depend on the installed CSL libraries), but LiveTraffic will do a bad job in supporting them to take off or land.

If you can't live with these limitations please don't try LiveTraffic. You might be disappointed.

LiveTraffic is no videocast from your favorite airport. It will not at all reflect the skilled maneuvers, with which Q400 pilot's achieve impressive landings in crosswind storm conditions.

LiveTraffic will fill your sky and (to a certain extend) airports with planes as they are operating in real life. It's one more bit of realism in your simulator. If you find that pretty cool then LiveTraffic is worth a try!