A publication of the National Air Traffic Controllers Association
Issue link: http://natca.uberflip.com/i/889675
• Mobile (MOB) ADS - B IOC 11/15 ADS - B Avionics Issues: An issue not screened by automation systems but an important assumption for future ADS - B dependent applications is the broadcast call sign of the user. ADS - B aircraft reports include this information, and automation systems c ompare to the filed call sign . When a mismatch occurs a Call Sign Mismatch (CSMM) alert can be generated. The SBS Article 114 work group has recommended disabling CSMM a lerts across all automation platforms. The issue has been highlighted in Equip 2020 meetings since ADS - B dependent applications (CAVS, Advanced Interval Management, etc.) are de pendent on this functionality. Monthly tracking continues to trend upward. 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, bureaucr acy, and legal constraints. These issues occur when standards for installation or configuration within aircraft or ground systems are not met. ADS - B is a cooperative surveillance source relying on the position information determined onboard the aircraft. 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 a n effective, efficient response mechanism is needed. The Agency has deployed additional mitigations including enhanced validation and a No Services Aircraft List (NSAL). Enhanced validation has a limited effect (15nm around a Te rminal Radar) on these issue s. Other validation techniques are also being investigated. Governance of th e NSAL has been a big concern. There is no formal governance at the moment and issues are being deal t with on a case - by - case basis. NATCA is working with the Agency to streamline this process, potential ly via an automated mechanism. The end result needs to be an effective means of identifying bad actors and reacting as close to real time as possible. SBS Article 114 work group discussions resulted in all B787 aircraft being placed on the NSAL. These aircraft have a latent avionics issue that causes false position information to b e displayed to the controller. This has alarmed several facilities and caused both SCT and NCT to demote ADS - B in their sort cell priorities. United and a few other foreign carriers have implemented a Boeing Service Bulletin that remedies the issue. Flight Standards verified the implementation, and all parties have now agreed to remove Unite d B787 aircraft from the NSAL. All other B787 aircraft will remain on the NSAL until verification of the Service Bulletin is received. Two events in August 2017 highlighted the inability to react effectively or efficiently to identify avionics problems. On Aug . 9, an ADS - B equipped Embraer 170 demonstrated extremely err atic tra cking within Houston Approach. The track was showing a zigzag or starburst behavior and actually split into four separate tracks at one point; three of which h ad identical full data blocks. The SBS Performance Monitor did flag the aircraft as non - c ompliant, but this data is currently only used post event . Flight Standards indicated they would qui ckly reach out to the operator. On Aug . 16, the same aircraft repeated it's bad tracking behavior at Potomac Appr oach while on Final to Dulles. The tracking left the