On 22 Apr, at 10Am, I watched a small, fixed-wing, single-engine turboprop aircraft orbit over my neighborhood for about 2 hours. I estimate its altitude at about 5,000 ft. It flew near-perfect circles, arriving at exactly the same point overhead exactly every 300 seconds. The location, less than 10 miles from IAD, is clearly within rhe Consolidated Potomac TRACON. None of the real-time tracking sites (FlightAware, ...) showed any aircraft flying that pattern, so I concluded that it was either not squawking ADS-B or Mode S, or that the web sites were requested to not track the flight.

I've seen this same behavior several times over the past few years with the orbit centered over different nearby areas.

How can I find out what this flight was doing or who it was?

  • $\begingroup$ Have you called the TRACON and asked them? $\endgroup$
    – Ralph J
    Commented Apr 26 at 14:53
  • $\begingroup$ Yes. I called. TRACON said they "could not divulge that information." Considering the area being observed and the aircraft, I doubt it was a local police operation- they usually use rotorcraft anyway. More likely a DHS training operation or some local tech company testing a new sensor of some sort. Still, it would be interesting to know what it was all about. $\endgroup$
    – Chucko
    Commented Apr 26 at 15:39
  • $\begingroup$ As discussed ADSBx is helpful, but in controlled airspace they are usually talking to tower or approach. “Idaho” is one call sign they use. $\endgroup$ Commented Apr 27 at 3:44

1 Answer 1


Your options are fairly limited. If you think it was broadcasting ADS-B or Mode S, you can check on one of the sites that does not respect requests to not publish ADS-B data, like ADS-B Exchange. You could even set up your own ADS-B receiver if you want to make sure your area has good coverage in the future.

Failing that, you could do an exhaustive search through LiveATC recordings to try to identify communications they made. If you believe it may be police or similar you may also be able to find recordings people made of local police scanners and other public communications.

The most sure way is the most low tech. Next time the aircraft passes by, go read its tail number with a spotting scope or a good pair of binoculars!

  • $\begingroup$ Thanks @chris, next time (?) I'll give ADS-B Exchange a look. At the altitude the aircraft was flying, I'd need a tripod-stabilized scope and a better angle than I've managed in the past. $\endgroup$
    – Chucko
    Commented Apr 26 at 19:12
  • $\begingroup$ @Chucko ADS-B Exchange lets you replay older data so you could give it a try now. Though I didn't see anything around KIAD flying a pattern like you described at a quick glance. $\endgroup$
    – Chris
    Commented Apr 26 at 19:36
  • $\begingroup$ I looked in real time, while the airplane was visible directly overhead. There was no ADS-B track displayed on any of several tracking sites. So I'm not surprised that historic replays showed nothing. Either the ADS-B track was being ignored by the tracking sites or, more likely, it was not squawking, alwas operating VFR and being tracked by TRACON as a primary radar target. $\endgroup$
    – Chucko
    Commented Apr 26 at 21:38
  • $\begingroup$ @Chucko Doesn't have to be a primary target. A mode 3/A transponder will not show up on tracking websites either. I mentioned ADS-B Exchange only because they very specifically refuse to ignore any data available to then. Granted they still might not have the data if there was no volunteer with a receiver in range. $\endgroup$
    – Chris
    Commented Apr 26 at 22:57
  • $\begingroup$ Reading the number with binoculars might be difficult, using a digital camera might be easier. Take several still photos and some video zoomed in on the plane, then when back home you can view the images on a computer monitor and zoom in on the registration number and hopefully make it out. A smart phone camera might be good enough, a digital camera with optical zoom probably even better. As for binoculars, see if your pair has a tripod screw hole on the front. If it does you can buy an inexpensive attachment that lets you mount the binoculars onto a tripod. $\endgroup$ Commented Apr 27 at 10:47

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