Signals May Be Unreliable April 7-15

GPS testing is scheduled for much of the central U.S. next week, which may result in unreliable or unavailable GPS signals.

According to an FAA NOTAM delivered to the media, the testing will be centered on the 013 degree radial of the VULCAN VORTAC near Birmingham, AL at 61 nautical miles April 07 – 15 between 0600Z – 1000Z.

NAV GPS (AFSMO GPS 18-22) (including WAAS, GBAS, and ADS-B) may not be available during the period within a 239 nautical mile radius of the center as follows:

• 239 nautical mile (nm) radius from FL400-UNL
• 191 nm radius at FL250
• 121 nm radius at 1,000 feet
• 82 nm radius at 400 feet AGL
• 35 nm radius at 50 ft AGL

Pilots are encouraged to report anomalies only when ATC assistance is required.

The NOTAMs discussed in this advisory may change with little or no notice. Pilots are advised to check NOTAMs frequently for possible changes prior to operations in the area. NOTAMs will be published at least 24 hours in advance of any GPS tests.

(Image provided with NOTAM)

FMI: www.faasafety.gov/files/notices/2018/Apr/AFSMO_18-22_GPS_Flight_Advisory.pdf