FlightAware Discussions

ADSB outage on east coast

Apparently affecting some flights.
Apologies if this is was posted earlier and I missed it.

https://hackaday.com/2019/06/09/gps-and-ads-b-problems-cause-cancelled-flights/

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So apparently ADSB is failing because of the GPS dependency. I thought there was something jamming the 1090 mhz signal. From other research I made apparently “GPS Outage” is misleading, what news outlets are quoting are the “RAIM” maps, which show places where the GPS signal integrity is not perfect.

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As I understand it, the RAIM map is a red herring; the “outages” shown are normal and expected (it’s to do with the number of satellites in view).

The actual problem seems to be specific to certain avionics:

https://www.fly.faa.gov/adv/adv_otherdis.jsp?advn=108&adv_date=06092019&facId=DCC&title=PRE+COORDINATION+OF+NON+TRANSPONDER+EQUIPPED+AIRCRAFT&titleDate=06/09/19

ISSUE: CURRENTLY CERTAIN AIRCRAFT EQUIPPED WITH THE ROCKWELL
COLLINS GPS 4000-100 AND SELECT ADS-B OUT GPS RECEIVERS ARE INDICATING
“ADS-B FAIL, UNAVAILABLE, TCAS FAIL OR TRANSPONDER FAIL” MESSAGES.

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It’s a software issue triggered by the next leap second appearing in the GPS almanac:

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