FlightAware.com and SkyView - different view


#1

I have several FlightAware alerts for friends with aircraft and been hosting piaware for few years. Saturday I received an email alert that one of my friends was near our home airport, so I looked him up on FA and sure enough he was in the pattern. I live 4mi from the airport with clear view of the sky so ADS-B visibility has always been great.

As I was tinkering with my piaware config I thought I’d compare what I was receiving from FA website and piaware, nothing showed on piaware (ADS-B cloaking on :wink: but there he was on FA. I could see the other aircraft in the pattern on piaware and FA.

There’s one thing unique about my friend’s aircraft (N961M) that may be contributing, under flight details on FA, it says: This flight is restricted from public view.
Unless I login to FA I can only see very old flights, login and I can see his current flights. I’ve asked him if he’s done anything to restrict the access and he indicates he has not.

Couple questions:
What is this restricted from public view all about for a general aviation aircraft? And how did it get that way? I could understand military/government wanting this but why GA, and the owner did nothing? I’ve read in the forums other examples of restricted aircraft but nothing regarding GA.

Could/would this restricted view have anything to do with not having piaware visibility of his aircraft position? I know it wouldn’t affect receiving ADS-B reports but perhaps piaware knows to filter them out of view based on being restricted??

Any suggestions for the dispirit view between PA and FA… I could understand ADS-B reception but I can see other aircraft that were not public restricted. I was mucking about in the db JSON files, customizing some of the aircraft data, perhaps a malformed JSON file could cause this behavior? I’ve thought to try reverting back to original JSON db files to see if that makes a difference but I’d have to wait until my friend is flying to confirm.


#2

PiAware default to only show planes if a message was seen in the last 60 seconds. If no new ADSB messages were seen then the plane is removed from the active plane list. There isn’t any long term storage built into PiAware. If a plane moves out of range it will be removed (planes are only stored in memory and not saved to disk).

Some people have setup a database to store all plane messages OR they would setup a computer to read the data feed and parse the data (something like Virtual Radar Server). Longer term storage on a SD card is not recommended but does work for a few months to a few years.

The restricted view on FA is because the pilot didn’t file a Flight Plan and not because they are GA. To view these flights a user needs to be logged into FlightAware and go into their account settings and click “show position only flights”. Position only flights are ones without a Flight Plan. These planes are normally flying under VFR.

There isn’t anything blocking piaware planes from showing up on the Skyview map. Most likely the plane was gone by the time you looked (you can change the "time to live’ timeout from the default 60 seconds).


#3

Thank you for clarification on restricted view, that makes total sense, and I missed the obvious troubleshooting steps of verifying others are the same, including my own flights. Mystery solved.

As to timeout, where is this configured? I found one in planeObject.js under lookup_aircraft_seen function, it’s set to 300 (seconds?)

What you describe would explain what I experienced but would not have been expected give my close proximity. Does FA only use ADS-B feeders? (someone else could see him but not me) or are there other sources such as TRACON radar?


#4

Actually I forgot where the value for time to live is set. I think it is a dump1090 setting and not the webpage setting.

dump1090-fa writes out the tracks to /var/run/dump1090
The webpage process the .json files for display.

Does FA only use ADS-B feeders?

FlightAware has many sources of data. Some sources are preferred over others for display on Flightaware.com .We use FAA radar (this includes TRACON) if there is no ADSB. This is because radar is accurate to a few Km while ADSB is accurate to a few meters (ADSB uses GPS for lat lon positions).

(someone else could see him but not me) or are there other sources such as TRACON radar?

Skyview is for ADSB, Mode-S , and MLAT. It usually only display messages your site is able to see directly.

If you click on a plane in Skyview it will display the RSSI (relative signal strength Indicator). Values higher than -2dB and lower than -40dB are hard to see. The gain setting can be used to see farther or closer. (default values is max gain).