Rv-9 pilot reported the failure of the garmin GNS480 waas GPS antenna caused the failure of the othe...

Narrative:

I experienced a failure of the garmin GNS480 waas GPS antenna in flight. The antenna failed in such a manner as to create spurious emissions that caused all other GPS antennas on my aircraft to also lose signal. The garmin GNS480 antenna on my aircraft is a GA-35 antenna approved for use with this unit. When the loss of position integrity occurred; I turned off the garmin GNS480 unit. Upon doing so; all other GPS receivers in my aircraft resumed normal operation. Immediately upon returning power to the garmin GNS480; all GPS receivers would again lose position lock. This repeatable sequence; and reports of similar failures including garmin communique #5; led me to the conclusion that the GA-35 antenna had failed in the same manner.I'm filing this report because; in my aircraft; the garmin GNS480 feeds GPS data to a trig tt-22 ads-B transponder; which would have failed ads-B position integrity upon failure of the GPS. While I was not in ads-B rule airspace (I was in airspace classes east and G for the duration of the event); I felt compelled to submit a report anyway in case of a future investigation of this incident. Had I been on an IFR flight plan; this would have been a reportable loss of navigation.

Original NASA ASRS Text

Title: RV-9 pilot reported the failure of the Garmin GNS480 WAAS GPS antenna caused the failure of the other GPS antennas in his aircraft. The issue was corrected when the pilot turned off the Garmin unit.

Narrative: I experienced a failure of the Garmin GNS480 WAAS GPS antenna in flight. The antenna failed in such a manner as to create spurious emissions that caused all other GPS antennas on my aircraft to also lose signal. The Garmin GNS480 antenna on my aircraft is a GA-35 antenna approved for use with this unit. When the loss of position integrity occurred; I turned off the Garmin GNS480 unit. Upon doing so; all other GPS receivers in my aircraft resumed normal operation. Immediately upon returning power to the Garmin GNS480; all GPS receivers would again lose position lock. This repeatable sequence; and reports of similar failures including Garmin Communique #5; led me to the conclusion that the GA-35 antenna had failed in the same manner.I'm filing this report because; in my aircraft; the Garmin GNS480 feeds GPS data to a Trig TT-22 ADS-B transponder; which would have failed ADS-B position integrity upon failure of the GPS. While I was not in ADS-B rule airspace (I was in airspace classes E and G for the duration of the event); I felt compelled to submit a report anyway in case of a future investigation of this incident. Had I been on an IFR flight plan; this would have been a reportable loss of navigation.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1525294
Time
Date	201703
Local Time Of Day	1201-1800
Place
Locale Reference	EQA.Airport
State Reference	KS
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	RV-9
Operating Under FAR Part	Part 91
Flight Phase	Descent
Route In Use	Direct
Flight Plan	VFR
Component
Aircraft Component	GPS & Other Satellite Navigation
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Instrument Flight Crew Private
Experience	Flight Crew Last 90 Days 20 Flight Crew Total 500 Flight Crew Type 350
Events
Anomaly	Aircraft Equipment Problem Less Severe

Rv-9 pilot reported the failure of the garmin GNS480 waas GPS antenna caused the failure of the other GPS antennas in his aircraft. The issue was corrected when the pilot turned off the garmin unit.