Air carrier pilot reported concerns with the periodic jamming of GPS signals by the military in the ...

Narrative:

The FAA has issued facsfacsd 17-02 advisory for GPS testing by our military. While I understand the need to test GPS performance; since aviation is dependent upon GPS for essential navigation; purposeful degradation of GPS navigation systems impairs aviation safety. The FAA is on schedule to continue the disablement of a majority of our ground based navigation systems; including vors; creating a dependence upon GPS and GNS system. GPS provides amazing capabilities for enroute and terminal operations.the continued testing of GPS degradation in the western us dramatically affects aviation navigation. This recent advisory is a good example of impact on a wide area of our country. As a professional pilot I have been affected by this activity while in flight; losing GPS navigation signals in class a airspace. When the signals are lost the autopilots also disconnect from navigation mode; resulting in a dangerous situation. After signal restoration; if the pilot does not notice that the ap is now in roll mode; this may result in nonconformance with the established flight plan.the broad time periods for testing also affects a very large time frame; which makes it nearly impossible for the pilots to accommodate. Imagine a pilot using the Q or T routes; or using GPS for approved NAVAID navigation or approaches and having the GPS signal degrade to the point of being unusable. This can have a direct impact on aviation safety.

Original NASA ASRS Text

Title: Air carrier pilot reported concerns with the periodic jamming of GPS signals by the military in the Southwest United States and its effect on flight safety.

Narrative: The FAA has issued FACSFACSD 17-02 advisory for GPS Testing by our military. While I understand the need to test GPS performance; since aviation is dependent upon GPS for essential navigation; purposeful degradation of GPS navigation systems impairs aviation safety. The FAA is on schedule to continue the disablement of a majority of our ground based navigation systems; including VORs; creating a dependence upon GPS and GNS system. GPS provides amazing capabilities for enroute and terminal operations.The continued testing of GPS degradation in the Western US dramatically affects aviation navigation. This recent advisory is a good example of impact on a wide area of our country. As a professional pilot I have been affected by this activity while in flight; losing GPS navigation signals in Class A airspace. When the signals are lost the autopilots also disconnect from NAV mode; resulting in a dangerous situation. After signal restoration; if the pilot does not notice that the AP is now in ROLL mode; this may result in nonconformance with the established flight plan.The broad time periods for testing also affects a very large time frame; which makes it nearly impossible for the pilots to accommodate. Imagine a pilot using the Q or T routes; or using GPS for approved NAVAID navigation or approaches and having the GPS signal degrade to the point of being unusable. This can have a direct impact on aviation safety.

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	1447444
Time
Date	201705
Local Time Of Day	1201-1800
Environment
Light	Daylight
Aircraft 1
Make Model Name	Commercial Fixed Wing
Person 1
Function	Captain
Qualification	Flight Crew Instrument Flight Crew Flight Instructor Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 80 Flight Crew Total 10400

Air carrier pilot reported concerns with the periodic jamming of GPS signals by the military in the southwest united states and its effect on flight safety.