JACKSONVILLE, Fla – FAA flight advisory shows jamming will target airspace 50 feet above the ground, up to 40,000 ft along the SE united States and the northwestern Bahamas.

Navigation guidance, ADS-B, and other GPS services could be affected for up to 400 nautical miles near northern Florida at upper flight levels.

Previous defense systems and preparedness exercises degraded GPS signals in February 2019.

The Aircraft Owners and Pilots Association (AOPA) considers the risks to general aviation navigation highly concerning.

AOPA, reports during previous exercises an aircraft lost navigation capability and did not regain it until after landing.

Other reports have highlighted aircraft veering off course and heading toward active military airspace—and the wide range of reports makes it clear that interference affects aircraft differently. In some cases, recovery from signal interference may not occur until well after the aircraft exits the jammed area.

Any pilots who encounter hazardous interruption of GPS navigation or who have flight-control issues should be aware that they can say the phrase “Stop buzzer” to air traffic control, which initiates the process of interrupting the testing to restore navigation signal reception.

Pilots should only use the phrase when communicating with ATC, or over the emergency frequency 121.5 MHz, if a safety-of-flight issue is encountered during a known GPS interference event.