View Full Version : Double line on FR24
susier
22nd Nov 2015, 08:33
Not sure if this link will work, but basically, there appears to be a double line following this plane:
Flightradar24.com - Live flight tracker! (http://www.flightradar24.com/CVK7025/80cacac)
I haven't noticed this before. Does anyone know what it means?
susier
22nd Nov 2015, 08:36
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/87129860@N04/23176779406/in/dateposted-public/
HEATHROW DIRECTOR
22nd Nov 2015, 08:58
Still looks like a single line to me..
susier
22nd Nov 2015, 09:08
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
22nd Nov 2015, 10:06
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
22nd Nov 2015, 10:28
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?