Mysterious interference causes planes to reroute in Texas

Aviation advisory warns of ‘anomolies that are dramatically impacting GPS’

A Southwest Airline plane flies past Reunion Tower on 4 April, 2013 in Dallas, Texas (Getty Images)

A mysterious GPS interference in Texas has forced aviation authorities to reroute flights and close a runway.

The Federal Aviation Administration (FAA) is currently investigating the issue with the global-positioning system used by aircraft, though claims that there is “no evidence of international interference”.

Dallas-Fort Worth International Airport temporarily closed one of its runways after GPS signals in the area became unreliable on Monday.

The possible signal-jamming impacted a 40-mile stretch of airspace, according to an Automatic Terminal Information Service (ATIS) advisory issued by the FAA.

Another advisory issued by the Air Traffic Control System Command Center warned pilots that they may need to revert to using “older ground navaid based arrivals and radar vectors” if their GPS signal was not functioning correctly.

“[Dallas-Fort Worth] is experiencing GPS anomalies that are dramatically impacting GPS,” the advisory stated.

“The cause is yet unknown. The length of this outage is therefore unpredictable and will remain in effect until further advised.”

A service that monitors GPS interference published a map of the impacted region, showing an area stretching right over the cities of Dallas and Fort Worth, as well as a second smaller area just north of Wichita Falls.

The interference began at around 1pm local time on Monday, according to GPSjam.org operator John Wiseman, who added that ground GPS signals were also affected.

A similarly mysterious incident occurred in Denver in January, when local Air Traffic Control issued a notice advising pilots about GPS problems.

The latest incident in Texas did not appear to be related to any military activity, according to Mr Wiseman, nor was it likely to have come from a solar flare due to the limited size of the area impacted.

“GPS uses an extremely low-power signal and can be easily jammed,” he tweeted. “Unfortunately my guess is that we’ll never know what caused this.”