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AOPA to co-chair study of GPS-outage impact AOPA to co-chair study of GPS-outage impact 

AOPA will co-chair an industry committee the FAA has called upon to study the impact of intentional GPS outages on flight operations-an issue of growing concern as the air traffic system becomes more dependent on core satellite-based navigation.

Photo by Mike Fizer.
Photo by Mike Fizer.

The FAA adopted an AOPA request that the Radio Technical Commission for Aeronautics (RTCA) assign its Tactical Operations Committee to assess the effects of planned GPS interference events on aviation. The FAA called for recommendations from the panel within the first quarter of fiscal year 2018.

Defense Department training and security exercises requiring intentional GPS and ADS-B interference are increasing, and “have a significant impact on General Aviation given the large size of the impacted area and the vagueness of the published description,” AOPA said in a summary the association has published of the issue’s impact on GA.

“In most cases, pilots are unclear on these interference events and their impact. The lack of detailed information can hinder adequate preflight planning and result in the unnecessary cancellation of flights. These incidents are receiving greater attention and raising questions as to how the [National Airspace System] can transition to primarily satellite-based technology if this technology will be routinely disrupted,” AOPA noted.

The lack of detail has produced notices to airmen about outages that “describe geographic GPS interference areas that are the size of multiple states and do not indicate likelihood of impact.” The notams are not always accompanied by a graphic, or an explanation of how the area of impact was calculated, AOPA said.

Also missing has been information about weather conditions that would cause a planned outage event to be called off.

“We need better information as we transition to a performance-based-navigation airspace system,” said Rune Duke, AOPA director of government affairs for airspace and air traffic. “Pilots want to know that their investments in ADS-B and wide area augmentation system, or WAAS, technology are going to produce the required returns.”

During a recent interference event conducted by the military in Alaska, a Pilatus PC-12 single-engine turboprop lost all GPS navigation capability, Duke said, adding, “It is important that pilots check notams, and if a pilot chooses to fly through an affected area, to have a backup plan.”

In its letter to RTCA, the FAA cited an AOPA survey of pilots that found that more than one-third had experienced a curtailment of GPS availability in flight.

More than 60 percent of those surveyed were concerned about the impact of intentional interference, and many pilots find notam alerts of exercises or outages to be “ineffective.”

Recommendations for improvements should address the alerting system, and propose guidance and training materials for air traffic controllers and pilots, the FAA said.

The private, nonprofit RTCA works in response to FAA requests “to develop comprehensive, industry-vetted and endorsed recommendations for the Federal government on issues ranging from technical performance standards to operational concepts for air transportation,” according to the organization’s website.

Another effort AOPA co-chaired, to improve the graphical charting of temporary flight restrictions, is moving forward as the FAA works to implement Tactical Operations Committee recommendations, the agency told the committee at its June 22 meeting.

Dan Namowitz

Dan Namowitz

Associate Editor Web
Associate Editor Web Dan Namowitz has been writing for AOPA in a variety of capacities since 1991. He has been a flight instructor since 1990 and is a 30-year AOPA member.
Topics: NextGen, Avionics, WAAS