Aircraft tracking way off actual route

CJW

New Member
#1
My son and his family flew down to Alicante from Gatwick last Thurday (Easyjet flight no EZY8667). I decided to track the last part of their flight and followed it down from north Spain expecting it to turn into Alicante when it got down there. I was surprised to see it continue to fly south in a straight line until it got almost to the south coast of Spain when it suddenly disappeared off the screen. As I always thought that the tracking was pretty accurate I must admit I started to wonder what had happened (even thought of a hijack, amazing what goes through your head). I sent them a text and much to my relief got a reply about 30 mins later. I can only assume that when the plane disappeared from the screen it was because it had landed but how did planefinder show it continuing to fly south and not track it into Alicante. Anyone any ideas please?
 
#2
Hi CJW,

Many commercial aircraft have ADS-B (Auto Dependent Surveillance-Broadcast) equipment onboard which broadcasts information such as location, altitude, heading, speed and squawk etc. Plane Finder works by receiving ADS-B data from the aircraft via an ADS-B Ground-Based Station. This information is then sent to Plane Finder servers and this is displayed on your screen. Without an ADS-B receiver at the location in which the aircraft is flying, Plane Finder cannot detect and display information for the aircraft flying in that location.

I had a look at the area around Alicante and there is no coverage around the airport. This means that no new data is available for your flight (EZY8667) to appear on Plane Finder when it was nearing Alicante Airport. There was coverage on an earlier stage of its flight and flight details are updated every 30 seconds (approx.) An aircraft may fly into and out of areas of ADS-B coverage many times in one single flight.

The reason in why you continued to see the aircraft fly in a straight line, pass the airfield and suddenly disappear from the screen is because there is a 'Flight Estimation' function which Plane Finder uses to estimate the location of an aircraft when there is no coverage around in the airspace that the aircraft was flying in. This function is very good in estimating the position of an aircraft as it is at the cruising stage of its flight. However, this function proves to be a inaccurate estimation as the aircraft is in its landing stage of its flight.

Plane Finder continued to track EZY8667's flight as it flew into an area without an ADS-B receiver. As you would have seen, the plane flew in a straight line without any other adjustments. After some time, the data would 'time out' as it would be inaccurate and the plane would simply disappear from the screen. You would have seen the 'Last Updated' line of the aircraft's information bar drag from 2 minutes to something like 10 or even 27 minutes.

If you had the 'Disable Flight Estimation' option disabled in the Plane tab of the Settings, EZY8667 would have not flown mysteriously off course and seem as though it were hijacked. Instead, it would stay in its last known position before changing position as new data was received for the plane. In your case, it would have stopped north-west of the airport and stay there until it 'timed out' and disappeared there.

There is not a quick fix to the problem. This problem can only be solved when someone in the area around Alicante offers to share ADS-B data with Plane Finder and significantly improve Plane Finder's coverage around that airport. The only thing that we can do now is wait!

I hope this solves your problem and please don't hesitate to ask me any more queries that you may have.

For your reading: http://planefinder.net/about/ads-b-how-planefinder-works/

All the Best for you and your Son's Family! ;)

Shine Wang :D
 
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