A publication of the National Air Traffic Controllers Association
Issue link: http://natca.uberflip.com/i/977826
ADS - B Avionics Issues: An issue not screened by automation systems but an important assumption for future ADS - B dependent applications is the br oadcast call sign of the user. ADS - B aircraft reports include this information, and automation systems comp are it to the filed call sign. When a mismatch occurs a Call Sign Mismatch (CS MM) alert can be generated. The issue has been highlighted in Equip 2020 meetings since ADS - B dependent applications (CAVS, Advanced Interval Management, etc.) are dependent on this functionality. Monthly track ing continues to trend upward. The SBS Arti cle 114 work group has recommended disabling CSMM alerts across all automation platforms. A flight test was conducted Feb . 27 to examine the effect of ADS - B Duplicate I CAO Address on ERAM and STARS. Engineering assumptions have always been that when this condition occurs with two aircraft within 6nm, the SBS network would either drop the tracks, swap the tracks or o ther. The initial results of the flight test show the events are much more conservative. Test aircraft as far apart as 50nm were still dropp ed from the network and pr esented as radar only targets. The SBS Article 114 work group has concluded that Duplicate ICAO Address alerts are n ot worthwhile for controllers. They will still be available for Flight Standards compliance monitoring efforts. N ATCA SBS continues to work with the Agency toward a more proactive approach to ADS - B avionics issues that result in position error. Though these are infrequent occurrences, the Agency's ability to respond has been hampered by a lack of resources, bureaucracy, and legal constraints. These issues occur when standards for installation or configuration within aircraft o r ground systems are not met. ADS - B is a cooperative surveillance source relying on the position information determined onboard the air craft. Multiple ATSAP reports have been file d on the known issues to date. Controllers and facilities are encouraged to report any identified events through ATSAP and any other mechanism. In order to reduce the number of safety compromising events in the NAS an effective, efficient response mechanism is needed. The Agency has deployed additional mitigations including enhanced validation (EV) and a No Services Aircraft List (NSAL). The NSAL (aka "blacklist") is effective in dealing with chronic non - compl iant aircraft, but it lacks t he ability to respond quickly. As such it will likely always be needed as a backstop to com pliance or enforcement issues. Any issue identified and reported immediately takes a minimum of one day to place the aircraft on the NSA L. Enhanced validation (EV) shows the most promise operationally as it is a real - time response to invalid ADS - B targ ets. The latest update to EV already deployed within 15nm around a Terminal Rad ar has shown positive results. Additional EV techniques are being analyzed, including expanding the range beyond 15nm and further increasing the responsiveness. SBS Engineering is working diligently with Harris to incorporate these changes with additional EV parameters in 2018. With 2020 approaching, rapidly, the se changes are needed sooner than later to limit the sporadic effects of non - compliant avionics. SBS Article 114 work group discussions resulted in all B787 airc raft being placed on the NSAL. These aircraft have a latent avionics issue that causes false p osition information to b e displayed to the controller. This has alarmed several facilities and caused both