Double line on FR24

[susier]

Not sure if this link will work, but basically, there appears to be a double line following this plane:


Flightradar24.com - Live flight tracker!


I haven't noticed this before. Does anyone know what it means?

[susier]

Ah. Showing as a single line on the link.

I have a screen shot but don't have permission to upload attachments. Sorry.


Here is a link to it on Flickr:


https://www.flickr.com/photos/871298...posted-public/

[HEATHROW DIRECTOR]

Still looks like a single line to me..

[susier]

It's not! Honest : ) Look at the bit directly above Calais. Two lines. They merge for most of the flight, but the line is thicker than usual, and they separate just there.


I wish I could zoom in and screenshot it again but it's disappeared now.

[DaveReidUK]

The An-12 in question doesn't transmit its position as it's not fitted with ADS-B.

So FR24 attempts to calculate it using a technique called Multilateration, based on the time difference between transponder signals arriving at different receivers.

That will be where the double tracks are being introduced.

[susier]

Thank you...I'm still puzzled as to why there is a double line, though.

A great number of A/C appear to be tracked on T-MLAT but I just haven't noticed this particular phenomenon before.

I think you are probably right, but if that's the case why does it not happen more often?