Local Flight Data Positioning Accuracy

[Skymaster]

Good morning everyone,

I believe that my home position is set accurately having used a variety of sources to verify it and that it should be in degrees and decimal minutes.

I recently saw on the box an approaching Fedex MD11 which, when abeam my house, I guessed would be about at 6 miles or so in an easterly direction based upon the view showing on the screen and the known distance to BHX, my "local" airport. As it was almost on me, I dashed outside with 'bins and was therefore somewhat surprised when it flew almost directly overhead with no course changes showing before it left the screen viewing area many miles to the SE.

Is this "error" down to my home position entry or something else - we do not get many overflights where I am so given good conditions things are very easy to pick up but in lesser conditions I need to know where to start looking!

Many thanks

Ron

[Runway 31]

Hi Ron,

I use Google Earth to set my position, you can zoom right in to your home and get very accurate details.  Also remember to use decimal for your location.

Hopefully this may help.

Alan

[RodBearden]

Hi Ron and welcome to the forum.

Another thing to remember that aircraft with older technology navigation systems can send wrong positional data. You are best to do a visual check with a more modern aircraft like later model A330 A340, A380, B77L, etc that use GPS rather than older inertial navigation systems.

I often see older aircraft like B733s missing the runway by miles when landing!

Hope that helps

Rod

[delconair]

Hello Rod,
                You have just answered the question I was about to ask. Last night I followed a number of aircraft, mainly easyjet into Glasgow however, there was one I believe a "Tom"....Flt, ahead of an easy. The latter landed miles to the north of Glasgow, and parallel to the easy which was spot on. I thought I may have being having problems with the latest radarbox updated version (3).Now I know different. Ta...
                                              Delconair. 

[RodBearden]

Delconair - it's a common problem that has been discussed many times on the forum.

An interesting by-product of the accuracy of GPS systems is that the few light aircraft that have ADS-B fitted always feed it with GPS, so their position is always spot-on.

Rod

[Skymaster]

Thanks for the replies guys

Ron