The Federal Aviation Administration (FDA) is warning pilots that secret military testing could leave the global-positioning signals (GPS) "unreliable or unavailable" for several days in June, across much of the West Coast. The alert was issues on Saturday, June 4.
The testing based in Southern California already began on Tuesday, June 7. The FAA warned that the tests could affect flight controls for a specific kind of business jet. However, according to experts, the testing shouldn't affect commercial airliners.
According to USA Today, John Cox, a former airline pilot and currently president of consulting firm Safety Operating Systems, said that usually in this kind of situations there "are safeguards in place." He added that air-traffic controllers and pilots will pay attention to any flight abnormalities on planes within the warning area. But in case that any pilot hears by radio about strange GPS signals in a given area, they could just navigate around the problem or adjust altitude in the same way they proceed in case of bad weather, Cox said.
The testing is taking place at Naval Air Warfare Center Weapons Division based in China Lake, California. According to FAA, the testing could affect aircraft within hundreds of miles of the base in case that they flight at least 50 feet off the ground to as high as 40,000 feet above sea level.
The affected area is the shape of an upside-down layer cake. The area is stretching across much of Utah, Idaho, Oregon and Arizona and is has the largest layer 40,000 feet high, spanning Nevada and California.
The Naval Air Warfare Center Weapons Division base said in a statement that the FAA flight advisory was issued in support of routine test, development, evaluation and research "efforts conducted at China Lake." China Lake, which encompasses 1.1 million acres, tests avionics and weapons for tactical aircraft.
According to Digital Trends, FAA did not specify the nature of the tests, since it is a secret military testing. However, based on FAA's statement, tech experts believe that this is some type of test of a jamming device. Some kind of interference is affecting the capability of aircraft to connect to GPS satellites in the area during the testing periods.