Flights into the Dallas area are being forced to take older,
cumbersome routes and a runway at Dallas-Fort Worth International
Airport was temporarily closed after aviation authorities said
GPS signals there aren't reliable.
The Federal Aviation Administration said in an emailed statement
Tuesday it's investigating the possible jamming of the
global-positioning system that aircraft increasingly use to guide them
on more efficient routes and to runways. So far, the agency has found
"no evidence of intentional interference," it said. American Airlines,
the primary carrier at DFW, said the GPS issue is not affecting its
operations. Southwest Airlines, which flies from nearby Love Field, said
it also isn't experiencing any disruptions. The FAA reopened the closed
runway earlier on Tuesday.
The GPS problem -- despite the lack of impact -- highlights the risk of
widespread reliance on the weak GPS radio signals from space used for
everything from timing stock trades to guiding jetliners. The FAA
occasionally warns pilots in advance of military testing that may
degrade the GPS signals and pilots sometimes report short-lived
problems, but the interference in Dallas is atypical, said Dan
Streufert, founder of the flight-tracking website ADSBexchange.com. "In
the US, it's very unusual to see this without a prior notice," Streufert
said in an interview. ADSBExchange.com monitors aircraft data streams
that indicate the accuracy of the GPS signals they are receiving and the
website began seeing problems around Dallas on Monday, he said. The
military has told the FAA it isn't conducting any operations that would
interfere with GPS in that area, said a person familiar with the
situation who wasn't authorized to speak publicly about it. The primary
way FAA's air-traffic system tracks planes is based on GPS, but older
radars and radio-direction beacons have remained in place as backups.