When Cleveland Cavaliers owner Dan Gilbert flew on his business aircraft to court Lebron James back to the team, aircraft watchers tracked the aircraft’s progress at websites that use ADS-B data to monitor aircraft that don’t pop up on publicly accessible FAA air traffic feeds. News outlets quickly reported Gilbert’s aircraft movements.

This, among other examples of public access to ADS-B information, has privacy advocates up in arms as the technology has the potential to dismantle FAA’s Block Aircraft Registration Request (BARR). Currently, aircraft operators can file for BARR, thereby denying access by unauthorized parties to air traffic control radar surveillance systems that track movements. BARR is used extensively by civilian and law enforcement aircraft operators to prevent stalkers and trackers from monitoring aircraft ID and position.

ADS-B, in contrast, broadcasts unencrypted Mode S transponder ID along with aircraft call sign, type, position and velocity vector. All 630 FAA ADS-B ground stations can receive unencrypted broadcast data, but so can anyone else within line-of-sight transmission range who has a consumer grade ADS-B receiver. Certain websites, such as FlightRadar24.com, already use ADS-B data obtained from such non-aviation sources to identify aircraft and track their positions because the message set isn’t encoded.

Aviation Week asked FAA Administrator Michael Huerta about ADS-B privacy issues at EAA AirVenture. The administrator said that people with mobile phones know that they can be tracked. So, ADS-B users may have to adapt to changing privacy standards as new technologies emerge.

NBAA, EAA, GAMA and other general aviation advocacy groups are deeply concerned about the issue. When asked if ADS-B avionics and ground station equipment needs to be upgraded with an encryption function, similar to the US military’s Link 16 system, Huerta said it’s worth analyzing, but he made no commitment beyond a general review of privacy issues.