7-minute lag from real airplane position


I live in the country, about 150 miles from the DFW area, and have a pretty open sky with which to observe high-altitude flights, which out here are pretty isolated.

I’ve noticed now with very clear consistency that there is a 7-minute lag between when the flight passes and when FlightAware shows it being there. It’s even more delayed with Flight Explorer AVWeb Edition, which lags by 11 minutes!

I know this is not Flight Explorer (and I’ll put the question to them too), but I remember when I was using them 3 years ago there was no lag at all. I would see a FedEx DC-10 on the map, look up with binoculars, and there it was! Now I’m having to wait for the radar returns to paint the plane over my house with both systems.



Please see the FAQ, How live is FlightAware’s tracking and status data?

The FAA says it’s for “security” although nobody is really able to define what this secures or how, if you’re wondering.


Understandable in today’s ‘terrorized’ culture, but it’s puzzling that the data wasn’t delayed in 2002/2003. I’ll await AvWeb’s response since it’s their system that was fine earlier but lags now.



I guess is so that you can’t just look at the current plane over head then go out and look at it throught the sites of a SAM.

Glad you’re only using binoculars :wink:


Usually, you can calcualte 8 miles a min. Do the math…it would have already traveled 56 miles in 7 mins. Would it still be visible if the weather was unlimited an no obstructions? Maybe if it had a contrail.


Does anyone have an actual reference for the delay requirement? Is it in the U.S. Code, or a FAR, or elsewhere in the CFR, or an Executive Order, or what? I’m wondering since it’s been stated in different form in various forums and mailing lists, and there seems to be a lot of folklore involved in these things. It would be good to see the actual legal requirement in black and white.

I mention this since, as a plane spotter, various officials, including police, private security, etc., have tried to tell me, “There’s a federal law against photographing aircraft!” and variations of that sort, including “It’s illegal to possess an aviation band scanner!” and similar. I’m not claiming the delay requirement is equally bogus, but I’d love to see the actual text.


The 5 minute delay is part of the contract requirements for an ASDI Class II feed. The DOT’s website about ASDI has more information.
The delay added by FlightAware to process the flight ranges from 5 to 60 seconds, so we usually say 5 - 6 minutes.


A lot of interesting reading at that site, thanks.