Viewpoint: Collateral Effects Of GPS Jamming

Industry trade groups are seeking to deal with issues related to the intentional jamming of Global Positioning Systems (GPS) for defense exercises and have asked the Department of Defense and the FAA for a briefing. 

While we recognize the military’s need to simulate loss of GPS, the growing practice is causing issues for pilots such as myself. 

One night near Crawford, Texas, cruising at FL310, my GPS failed. I was flying an SF50 Vision Jet Generation Two. I turned to my CFO and confidentially stated, “Don’t worry; we have a backup.”

But switching to backup, I also got a fail message. If there was any weather, we were above it with a bright star field. I could see no reason why two independent GPS units with two separate antennas would fail simultaneously. And I wasn’t sure what to do. 

Being in RVSM airspace, a GPS fail felt like an excellent reason to inform ATC and request an immediate descent, if not declare an emergency. 

When I called ATC to report the GPS failure, several airliners joined the conversation and reported the same issue. One stated categorically it was GPS jamming. 

ATC did not order me to descend, and all seemed business as usual. As it was later in the evening, there was not much flight-level traffic, and I did not perceive any collision safety risk, but I was anxious concerning RVSM operations. What to do with an instrument fail in RVSM? 

Any altimeter or altitude control system or altitude alerter fails, and your actions are well defined; call it in and request clearance out of RVSM airspace. 

The experience has had lingering consequences for my aircraft.

For example, our Vision Jet forgot its N Number identifier on this flight in this timeframe. I later learned this is caused by a transponder failover with a potential conflict of ADS-B settings.

I’m not familiar with GPS jamming methods, but it took several conversations with Cirrus Maintenance Personnel to reset the ADS-B /Transponder settings to cure our airframe’s amnesia. There did seem to be lasting flight deck impact from this encounter requiring intervention to restore. 

I can appreciate the security requirement to jam GPS signals, but perhaps this could be done with consideration for the integrity of the U.S. airspace system. 

Richard Kane is Chairman and CEO of Verijet, based in Boca Raton, Florida.