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GPS interference testing will affect large swath of Alaska airspace

Colleen Mondor

The Federal Aviation Administration released a flight advisory last week concerning scheduled GPS interference testing based in the Big Delta area. From Aug. 11-24, GPS testing may result in unreliable or unavailable signals ranging outward from Big Delta to 365 nautical miles and up to 40,000 feet.

Centered at 634714N/1455152W or the BIG VOR 173 degree radial at 014NM, the tests will affect the surrounding area as follows:

• Within a 340 nautical mile radius to an altitude of 40,000 feet and higher
• Within a 293 nautical mile radius to an altitude of 25,000 feet and higher
• Within a 214 nautical mile radius to an altitude of 10,000 feet and higher
• Within a 192 nautical mile radius to an altitude of 4,000 feet and higher
• Within a 114 nautical mile radius to an altitude of 50 feet and higher

Pilots are encouraged to report all GPS anomalies in the area during testing to Anchorage Center to assist in measuring the extent of signal degradation.

Notices to Airmen (NOTAMS) will be issued and updated throughout the testing period. Pilots flying through the area should check NOTAMS frequently as testing periods may change. The FAA advises that NOTAMS will be issued 24 hours in advance of all testing.   The current scheduled times for the testing are as follows:

Aug. 11: 9:50 a.m. - 12:30 p.m.
Aug. 12-15: 4:15 p.m. - 5:15 p.m. and 9:50 a.m. - 12:30 p.m.
Aug. 16: 4:15 p.m. - 5:15 p.m.
Aug. 18: 9:50 a.m. - 12:30 p.m.
Aug. 19-21: 4:15 p.m. - 5:15 p.m. and 9:50 a.m. - 12:30 p.m.
Aug. 22: 4:15 p.m. - 5:15 p.m.

Update: The government agency conducting the testing is the Department of Defense, based in Fort Greeley. For more information, see this website.

Contact Colleen Mondor at colleen@alaskadispatch.com.