July 19, 2016

AT&T has launched an experimental 5G cell phone system in the Austin, TX, area, which operates on a frequency immediately next to the frequencies used by aircraft radio altimeters.

AT&T engineers believe the 5G tests will not impact aircraft operating to and from Austin-Bergstrom International Airport (AUS), said Bob Lamond, NBAA director of air traffic services and infrastructure, but NBAA recommends that operators remain vigilant for any possible interference.

NBAA urges members operating in the area to closely monitor the performance of their radio altimeters, and immediately notify ATC should they experience any interference.

AT&T will have three phases of testing over approximately three years. The inaugural phase, which began July 18, is expected to end Aug. 26, 2016. Subsequent test phases have not yet been published.

While any interference should be immediately reported on frequency, pilots are asked to contact Andrew Roy, from Aviation Spectrum Resources, Inc., via email at ACR@asri.aero after landing.

To receive the experimental FCC license, AT&T conducted an analysis using generic altimeter performance specifications, said Roy. The analysis found that the 5G tests would not affect performance “unless in extremely close proximity to the transmitting tower (even with a safety margin applied).”

The 5G base station is located at 30°23’27.48″N, 97°45’5.12″W, and covers an area of 5 kilometers from this center point. One of the requirements of the experimental license is that AT&T is responsible for avoiding interference and must modify its emissions, if needed.