Narrative:

The FAA has mandated the use of ads-B for separation by controllers in the state of alaska at anchorage ARTCC. Until recently it was not certified to be used with radar/transponder targets. The fact was unknown to the controllers who separated ads-B (green targets) from transponder (yellow targets) using the basic 5 miles separation. The management staff were aware that the controllers were unknowingly using illegal separation for over 4 years but did not address this because; as they stated; the alternative was to discontinue ads-B on the radar. In about march 2006; when controllers addressed the issue; the agency turned the ads-B off. The ads-B was returned to controller scopes on june/thur/2006; and an ads-B 'box' was displayed. The purpose of the box was to show controllers the only area where the ads-B was being displayed. Magically controllers are now allowed to separate yellow targets from green targets using 5 miles. The advent of the box has not addressed the safety issues that have been identified for years. It is time someone outside the agency looks at the system and its many safety issues. It is the intent of the FAA to expand this problematic system to other large areas of the state for separation purposes without attempting to fix it. The following is a synopsis of the safety problems that have been identified by controllers. Aircraft are constantly and continuously 'conflicting with itself.' this causes the conflict alert horn to sound and give a visual 'ca' flashing on the controller's radar scope. The hazardous effect is that due to the great number of nuisance alarms while working traffic; the controllers tend to ignore the alarm to keep up other duties in a busy environment. The agency explained that it was a known error occurring in a known area. In fact; controller discrepancy reports for the weeks in july document it in 6 different areas. The agency blames the problem as a tracking issue within micro-earts two sensors; primary and secondary radar returns. The reality is that this does not happen to an aircraft that is not ads-B equipped. The agency deflects the blame by concluding that 'while this is not an ads-B anomaly; ads-B is a contributing factor.' the agency admits the problem must be resolved but has no fix or implementation date. For some unknown reason to us; a data block flashes 'ICAO' on the radar scope. The agency blames it on pilot error in the cockpit. The controller must do a computer entry on the radar target to make it go away. The explanation that the pilot is doing something with the avionics is not verifiable by the agency and appears to be a best guess to why it happens. A new box around the ads-B area which segregates the ads-B from being displayed outside the box is now displayed on the radar scope. Aircraft without a functioning transponder have been erroneously tracked outside the box as an ads-B target. The agency explanation of the new anomaly does not explain why the target is shown outside the ads-B only box. Additionally; the most serious problem is the system allows data from one aircraft to xfer to another aircraft without controller input or knowledge. In these instances; an aircraft that goes into coast mode (approach to airports) because the radar stopped tracking them; can have their data tag picked up by an unassociated ads-B aircraft and begin tracking that aircraft. The system now shows the first non ads-B aircraft as now having ads-B. The agency claim that this is normal is absurd. Data tag swaps are unacceptable anywhere else in the system. The agency claim that this is a micro-earts problem is incorrect. Micro-earts should be modified to correct this if ads-B is to be integrated into micro-earts. This would be akin to putting a 40 inch monitor into a console where a 30 inch monitor should be and saying it is the console's problem. Controllers have been instructed that they must be aware of using radar separation on aircraft that are leaving the ads-B area without a transponder. The target will disappear leaving the box. There is no way for a controller to know that an aircraft is ads-B equipped without a transponder. There is no equipment suffix forads-B. Controller workload and complexity has been complicated by the fact that an aircraft mode C altitude must be verified every time the aircraft data block turns from ads-B (green) to radar (yellow) and vice versa. This requires more frequency xmissions between controller/pilot. There are numerous instances of aircraft having the discrete code in the transponder with the matching code in the ads-B box. The ads-B; when displayed on the controller scope will only show 1200 and appear as a VFR target in near the exact position and altitude as the radar displayed target. Air taxi operators have been known to put 'ads-B only displays 1200' in the remarks section. The agency explained this as pilot error and modified the system so the pilot was required to reset his ads-B code. With the problem still occurring; the agency continues to say it is pilot error but no explanation what the error is. Aircraft that are not ads-B equipped but have xponders are not being displayed or filtered from appearing on the radar scopes both in and outside the confines of the ads-B box. This does not happen to all aircraft. It is a small percentage but an unacceptable number. These aircraft should be displayed as transponder targets on the scope. They are departing bethel or other areas in the 'ads-B box' and exiting the box both laterally and vertically. The top of the box is 6000 ft. Some climb out of the roof of the box. The aircraft is now at 12000 ft and should be displayed. It does not appear on the scopes until crossing the lateral confines of the box and then magically appears as a radar target. Again; the agency claim that this is an m-earts problem is not correct. It is the addition of the ads-B box that appears to be causing the problem. These problems have been labeled by the ads-B reps in the building as 'workarounds.' they are somewhat manageable (not acceptable) when they are in an isolated area at bethel. To spread these safety issues to other areas is not acceptable and should not be allowed on aug/sat/2006; as the agency order states. We have been told these issues are not ads-B problems time and time again; including in a 'read and initial' the facility put out in july. The truth of the matter is that all of these problems are because of the use of the ads-B equipment. If that is not the case; we need to start looking at the other parts of the system that they are blaming (pilots; radars; micro-earts; controllers).callback conversation with reporter revealed the following information: the reporter indicated that the FAA pressure to make ads-B work is continuing and added that this system; was in their opinion; close to 85 percent successful. The reporter restated that the problem was not associated with micro-earts; as alleged by the FAA; but was the interface between the ads-B and the micro-earts. The reporter again stated the concern; that until the problems are resolved; the ads-B should not be implemented in other areas of the ATC system.

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Original NASA ASRS Text

Title: ZAN CTLR EXPRESSED CONCERN REGARDING ACFT SEPARATION USING FAA MANDATED ADS-B EQUIP AND PROCS.

Narrative: THE FAA HAS MANDATED THE USE OF ADS-B FOR SEPARATION BY CTLRS IN THE STATE OF ALASKA AT ANCHORAGE ARTCC. UNTIL RECENTLY IT WAS NOT CERTIFIED TO BE USED WITH RADAR/XPONDER TARGETS. THE FACT WAS UNKNOWN TO THE CTLRS WHO SEPARATED ADS-B (GREEN TARGETS) FROM XPONDER (YELLOW TARGETS) USING THE BASIC 5 MILES SEPARATION. THE MANAGEMENT STAFF WERE AWARE THAT THE CTLRS WERE UNKNOWINGLY USING ILLEGAL SEPARATION FOR OVER 4 YEARS BUT DID NOT ADDRESS THIS BECAUSE; AS THEY STATED; THE ALTERNATIVE WAS TO DISCONTINUE ADS-B ON THE RADAR. IN ABOUT MARCH 2006; WHEN CTLRS ADDRESSED THE ISSUE; THE AGENCY TURNED THE ADS-B OFF. THE ADS-B WAS RETURNED TO CTLR SCOPES ON JUNE/THUR/2006; AND AN ADS-B 'BOX' WAS DISPLAYED. THE PURPOSE OF THE BOX WAS TO SHOW CTLRS THE ONLY AREA WHERE THE ADS-B WAS BEING DISPLAYED. MAGICALLY CTLRS ARE NOW ALLOWED TO SEPARATE YELLOW TARGETS FROM GREEN TARGETS USING 5 MILES. THE ADVENT OF THE BOX HAS NOT ADDRESSED THE SAFETY ISSUES THAT HAVE BEEN IDENTIFIED FOR YEARS. IT IS TIME SOMEONE OUTSIDE THE AGENCY LOOKS AT THE SYSTEM AND ITS MANY SAFETY ISSUES. IT IS THE INTENT OF THE FAA TO EXPAND THIS PROBLEMATIC SYSTEM TO OTHER LARGE AREAS OF THE STATE FOR SEPARATION PURPOSES WITHOUT ATTEMPTING TO FIX IT. THE FOLLOWING IS A SYNOPSIS OF THE SAFETY PROBS THAT HAVE BEEN IDENTIFIED BY CTLRS. ACFT ARE CONSTANTLY AND CONTINUOUSLY 'CONFLICTING WITH ITSELF.' THIS CAUSES THE CONFLICT ALERT HORN TO SOUND AND GIVE A VISUAL 'CA' FLASHING ON THE CTLR'S RADAR SCOPE. THE HAZARDOUS EFFECT IS THAT DUE TO THE GREAT NUMBER OF NUISANCE ALARMS WHILE WORKING TFC; THE CTLRS TEND TO IGNORE THE ALARM TO KEEP UP OTHER DUTIES IN A BUSY ENVIRONMENT. THE AGENCY EXPLAINED THAT IT WAS A KNOWN ERROR OCCURRING IN A KNOWN AREA. IN FACT; CTLR DISCREPANCY RPTS FOR THE WEEKS IN JULY DOCUMENT IT IN 6 DIFFERENT AREAS. THE AGENCY BLAMES THE PROBLEM AS A TRACKING ISSUE WITHIN MICRO-EARTS TWO SENSORS; PRIMARY AND SECONDARY RADAR RETURNS. THE REALITY IS THAT THIS DOES NOT HAPPEN TO AN ACFT THAT IS NOT ADS-B EQUIPPED. THE AGENCY DEFLECTS THE BLAME BY CONCLUDING THAT 'WHILE THIS IS NOT AN ADS-B ANOMALY; ADS-B IS A CONTRIBUTING FACTOR.' THE AGENCY ADMITS THE PROB MUST BE RESOLVED BUT HAS NO FIX OR IMPLEMENTATION DATE. FOR SOME UNKNOWN REASON TO US; A DATA BLOCK FLASHES 'ICAO' ON THE RADAR SCOPE. THE AGENCY BLAMES IT ON PLT ERROR IN THE COCKPIT. THE CTLR MUST DO A COMPUTER ENTRY ON THE RADAR TARGET TO MAKE IT GO AWAY. THE EXPLANATION THAT THE PLT IS DOING SOMETHING WITH THE AVIONICS IS NOT VERIFIABLE BY THE AGENCY AND APPEARS TO BE A BEST GUESS TO WHY IT HAPPENS. A NEW BOX AROUND THE ADS-B AREA WHICH SEGREGATES THE ADS-B FROM BEING DISPLAYED OUTSIDE THE BOX IS NOW DISPLAYED ON THE RADAR SCOPE. ACFT WITHOUT A FUNCTIONING XPONDER HAVE BEEN ERRONEOUSLY TRACKED OUTSIDE THE BOX AS AN ADS-B TARGET. THE AGENCY EXPLANATION OF THE NEW ANOMALY DOES NOT EXPLAIN WHY THE TARGET IS SHOWN OUTSIDE THE ADS-B ONLY BOX. ADDITIONALLY; THE MOST SERIOUS PROB IS THE SYSTEM ALLOWS DATA FROM ONE ACFT TO XFER TO ANOTHER ACFT WITHOUT CTLR INPUT OR KNOWLEDGE. IN THESE INSTANCES; AN ACFT THAT GOES INTO COAST MODE (APCH TO ARPTS) BECAUSE THE RADAR STOPPED TRACKING THEM; CAN HAVE THEIR DATA TAG PICKED UP BY AN UNASSOCIATED ADS-B ACFT AND BEGIN TRACKING THAT ACFT. THE SYSTEM NOW SHOWS THE FIRST NON ADS-B ACFT AS NOW HAVING ADS-B. THE AGENCY CLAIM THAT THIS IS NORMAL IS ABSURD. DATA TAG SWAPS ARE UNACCEPTABLE ANYWHERE ELSE IN THE SYSTEM. THE AGENCY CLAIM THAT THIS IS A MICRO-EARTS PROB IS INCORRECT. MICRO-EARTS SHOULD BE MODIFIED TO CORRECT THIS IF ADS-B IS TO BE INTEGRATED INTO MICRO-EARTS. THIS WOULD BE AKIN TO PUTTING A 40 INCH MONITOR INTO A CONSOLE WHERE A 30 INCH MONITOR SHOULD BE AND SAYING IT IS THE CONSOLE'S PROB. CTLRS HAVE BEEN INSTRUCTED THAT THEY MUST BE AWARE OF USING RADAR SEPARATION ON ACFT THAT ARE LEAVING THE ADS-B AREA WITHOUT A XPONDER. THE TARGET WILL DISAPPEAR LEAVING THE BOX. THERE IS NO WAY FOR A CTLR TO KNOW THAT AN ACFT IS ADS-B EQUIPPED WITHOUT A XPONDER. THERE IS NO EQUIP SUFFIX FORADS-B. CTLR WORKLOAD AND COMPLEXITY HAS BEEN COMPLICATED BY THE FACT THAT AN ACFT MODE C ALT MUST BE VERIFIED EVERY TIME THE ACFT DATA BLOCK TURNS FROM ADS-B (GREEN) TO RADAR (YELLOW) AND VICE VERSA. THIS REQUIRES MORE FREQ XMISSIONS BETWEEN CTLR/PLT. THERE ARE NUMEROUS INSTANCES OF ACFT HAVING THE DISCRETE CODE IN THE XPONDER WITH THE MATCHING CODE IN THE ADS-B BOX. THE ADS-B; WHEN DISPLAYED ON THE CTLR SCOPE WILL ONLY SHOW 1200 AND APPEAR AS A VFR TARGET IN NEAR THE EXACT POSITION AND ALT AS THE RADAR DISPLAYED TARGET. AIR TAXI OPERATORS HAVE BEEN KNOWN TO PUT 'ADS-B ONLY DISPLAYS 1200' IN THE REMARKS SECTION. THE AGENCY EXPLAINED THIS AS PLT ERROR AND MODIFIED THE SYSTEM SO THE PLT WAS REQUIRED TO RESET HIS ADS-B CODE. WITH THE PROB STILL OCCURRING; THE AGENCY CONTINUES TO SAY IT IS PLT ERROR BUT NO EXPLANATION WHAT THE ERROR IS. ACFT THAT ARE NOT ADS-B EQUIPPED BUT HAVE XPONDERS ARE NOT BEING DISPLAYED OR FILTERED FROM APPEARING ON THE RADAR SCOPES BOTH IN AND OUTSIDE THE CONFINES OF THE ADS-B BOX. THIS DOES NOT HAPPEN TO ALL ACFT. IT IS A SMALL PERCENTAGE BUT AN UNACCEPTABLE NUMBER. THESE ACFT SHOULD BE DISPLAYED AS XPONDER TARGETS ON THE SCOPE. THEY ARE DEPARTING BETHEL OR OTHER AREAS IN THE 'ADS-B BOX' AND EXITING THE BOX BOTH LATERALLY AND VERTICALLY. THE TOP OF THE BOX IS 6000 FT. SOME CLB OUT OF THE ROOF OF THE BOX. THE ACFT IS NOW AT 12000 FT AND SHOULD BE DISPLAYED. IT DOES NOT APPEAR ON THE SCOPES UNTIL CROSSING THE LATERAL CONFINES OF THE BOX AND THEN MAGICALLY APPEARS AS A RADAR TARGET. AGAIN; THE AGENCY CLAIM THAT THIS IS AN M-EARTS PROB IS NOT CORRECT. IT IS THE ADDITION OF THE ADS-B BOX THAT APPEARS TO BE CAUSING THE PROB. THESE PROBS HAVE BEEN LABELED BY THE ADS-B REPS IN THE BUILDING AS 'WORKAROUNDS.' THEY ARE SOMEWHAT MANAGEABLE (NOT ACCEPTABLE) WHEN THEY ARE IN AN ISOLATED AREA AT BETHEL. TO SPREAD THESE SAFETY ISSUES TO OTHER AREAS IS NOT ACCEPTABLE AND SHOULD NOT BE ALLOWED ON AUG/SAT/2006; AS THE AGENCY ORDER STATES. WE HAVE BEEN TOLD THESE ISSUES ARE NOT ADS-B PROBS TIME AND TIME AGAIN; INCLUDING IN A 'READ AND INITIAL' THE FACILITY PUT OUT IN JULY. THE TRUTH OF THE MATTER IS THAT ALL OF THESE PROBS ARE BECAUSE OF THE USE OF THE ADS-B EQUIP. IF THAT IS NOT THE CASE; WE NEED TO START LOOKING AT THE OTHER PARTS OF THE SYSTEM THAT THEY ARE BLAMING (PLTS; RADARS; MICRO-EARTS; CTLRS).CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR INDICATED THAT THE FAA PRESSURE TO MAKE ADS-B WORK IS CONTINUING AND ADDED THAT THIS SYSTEM; WAS IN THEIR OPINION; CLOSE TO 85 PERCENT SUCCESSFUL. THE RPTR RESTATED THAT THE PROB WAS NOT ASSOCIATED WITH MICRO-EARTS; AS ALLEGED BY THE FAA; BUT WAS THE INTERFACE BETWEEN THE ADS-B AND THE MICRO-EARTS. THE RPTR AGAIN STATED THE CONCERN; THAT UNTIL THE PROBS ARE RESOLVED; THE ADS-B SHOULD NOT BE IMPLEMENTED IN OTHER AREAS OF THE ATC SYSTEM.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.