Narrative:

As I was working a radar position during a time period of heavy WX, multiple aircraft were on vectors for approach and I was trying to provide WX advisories according to ASR-9 6 level WX returns. The WX returns were not accurate according to aircraft. Aircraft were flatly refusing to enter clear or low level WX echo areas due to their airborne radar information. Other aircraft were flying right through level 4-5 WX echoes reporting no problems. We have had previous problems with this system. Approximately 2-3 months ago, I noticed a problem with the WX returns and the source was tracked to an automatic circular polarization circuit. The same problems were noted on this occasion. The linear polarization circuits were showing substantially fewer returns than the circular polarization circuits. On the first occasion, airways facilities replaced a card in the ASR-9 and then had to re-do a clear day map to set the WX return levels. On this occasion, 2 radar technicians, multiple controllers, 2 supervisors and others witnessed the events. The system was logged out on apr/fri/03. The lead radar technician for the ASR-9 advised the morning of apr/sat/03 that the tests for intensities checked normal. He agreed the WX circuits are not right, but can do nothing about it. I advised him of the chaos and hazardous conditions that not having accurate WX causes. He replied that the technicians at bhm requested an ASR-9 optimization check, but were refused. We display ASR-9 data on stars displays (ARTS or stars). I advised the technician that I felt very strongly about the situation. He said he knew how I felt and hoped we could get a radar optimization specialist down to fix the system. WX services are a high priority service to all aircraft. If this situation is not resolved, some of our younger controllers who don't have the experience are going to take somebody through a level 5 or 6 thunderstorm and they are not going to come out. The situation I had with this the other day was horrible. I had aircraft turing on their own, refusing headings and generally avoiding areas of level 1 and 2 returns that were actually much higher. I just didn't know what they were because of the ASR-9 situation. We also have ghost level 2 WX echoes that will display on the stars display, but will not be shown as an available WX intensity to select. This has also been witnessed and verified. We have vectored aircraft around these returns and the pilots have verified the return was false. I wanted to report this situation to ASRS so that these safety related sits can be monitored and or trended. Callback conversation with reporter revealed the following information: reporter advised circular polarization issue was resolved. The error was determined as a failure in the electromechanical gate switch in the circular polarization circuitry. WX would activate the automatic circular polarization circuitry, but would fail to fully engage, even though indicating the activation was completed. The controller advised that the problem was initially idented in jan/03. The controller advised that maintenance initially thought the clear air map was the problem. The controller alleged that it took months for management and maintenance to arrive at the conclusion that a radar optimization evaluation was required to identify the real problem.

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Original NASA ASRS Text

Title: BHM CTLR ALLEGES ASR-9 CIRCULAR POLARIZATION ANOMALY ERRORS IN PAINTING LEVEL 5-6 WX ECHO RETURNS ON CTLR STARS DISPLAY.

Narrative: AS I WAS WORKING A RADAR POS DURING A TIME PERIOD OF HVY WX, MULTIPLE ACFT WERE ON VECTORS FOR APCH AND I WAS TRYING TO PROVIDE WX ADVISORIES ACCORDING TO ASR-9 6 LEVEL WX RETURNS. THE WX RETURNS WERE NOT ACCURATE ACCORDING TO ACFT. ACFT WERE FLATLY REFUSING TO ENTER CLR OR LOW LEVEL WX ECHO AREAS DUE TO THEIR AIRBORNE RADAR INFO. OTHER ACFT WERE FLYING RIGHT THROUGH LEVEL 4-5 WX ECHOES RPTING NO PROBS. WE HAVE HAD PREVIOUS PROBS WITH THIS SYS. APPROX 2-3 MONTHS AGO, I NOTICED A PROB WITH THE WX RETURNS AND THE SOURCE WAS TRACKED TO AN AUTOMATIC CIRCULAR POLARIZATION CIRCUIT. THE SAME PROBS WERE NOTED ON THIS OCCASION. THE LINEAR POLARIZATION CIRCUITS WERE SHOWING SUBSTANTIALLY FEWER RETURNS THAN THE CIRCULAR POLARIZATION CIRCUITS. ON THE FIRST OCCASION, AIRWAYS FACILITIES REPLACED A CARD IN THE ASR-9 AND THEN HAD TO RE-DO A CLR DAY MAP TO SET THE WX RETURN LEVELS. ON THIS OCCASION, 2 RADAR TECHNICIANS, MULTIPLE CTLRS, 2 SUPVRS AND OTHERS WITNESSED THE EVENTS. THE SYS WAS LOGGED OUT ON APR/FRI/03. THE LEAD RADAR TECHNICIAN FOR THE ASR-9 ADVISED THE MORNING OF APR/SAT/03 THAT THE TESTS FOR INTENSITIES CHKED NORMAL. HE AGREED THE WX CIRCUITS ARE NOT RIGHT, BUT CAN DO NOTHING ABOUT IT. I ADVISED HIM OF THE CHAOS AND HAZARDOUS CONDITIONS THAT NOT HAVING ACCURATE WX CAUSES. HE REPLIED THAT THE TECHNICIANS AT BHM REQUESTED AN ASR-9 OPTIMIZATION CHK, BUT WERE REFUSED. WE DISPLAY ASR-9 DATA ON STARS DISPLAYS (ARTS OR STARS). I ADVISED THE TECHNICIAN THAT I FELT VERY STRONGLY ABOUT THE SIT. HE SAID HE KNEW HOW I FELT AND HOPED WE COULD GET A RADAR OPTIMIZATION SPECIALIST DOWN TO FIX THE SYS. WX SVCS ARE A HIGH PRIORITY SVC TO ALL ACFT. IF THIS SIT IS NOT RESOLVED, SOME OF OUR YOUNGER CTLRS WHO DON'T HAVE THE EXPERIENCE ARE GOING TO TAKE SOMEBODY THROUGH A LEVEL 5 OR 6 TSTM AND THEY ARE NOT GOING TO COME OUT. THE SIT I HAD WITH THIS THE OTHER DAY WAS HORRIBLE. I HAD ACFT TURING ON THEIR OWN, REFUSING HDGS AND GENERALLY AVOIDING AREAS OF LEVEL 1 AND 2 RETURNS THAT WERE ACTUALLY MUCH HIGHER. I JUST DIDN'T KNOW WHAT THEY WERE BECAUSE OF THE ASR-9 SIT. WE ALSO HAVE GHOST LEVEL 2 WX ECHOES THAT WILL DISPLAY ON THE STARS DISPLAY, BUT WILL NOT BE SHOWN AS AN AVAILABLE WX INTENSITY TO SELECT. THIS HAS ALSO BEEN WITNESSED AND VERIFIED. WE HAVE VECTORED ACFT AROUND THESE RETURNS AND THE PLTS HAVE VERIFIED THE RETURN WAS FALSE. I WANTED TO RPT THIS SIT TO ASRS SO THAT THESE SAFETY RELATED SITS CAN BE MONITORED AND OR TRENDED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR ADVISED CIRCULAR POLARIZATION ISSUE WAS RESOLVED. THE ERROR WAS DETERMINED AS A FAILURE IN THE ELECTROMECHANICAL GATE SWITCH IN THE CIRCULAR POLARIZATION CIRCUITRY. WX WOULD ACTIVATE THE AUTO CIRCULAR POLARIZATION CIRCUITRY, BUT WOULD FAIL TO FULLY ENGAGE, EVEN THOUGH INDICATING THE ACTIVATION WAS COMPLETED. THE CTLR ADVISED THAT THE PROB WAS INITIALLY IDENTED IN JAN/03. THE CTLR ADVISED THAT MAINT INITIALLY THOUGHT THE CLR AIR MAP WAS THE PROB. THE CTLR ALLEGED THAT IT TOOK MONTHS FOR MGMNT AND MAINT TO ARRIVE AT THE CONCLUSION THAT A RADAR OPTIMIZATION EVALUATION WAS REQUIRED TO IDENT THE REAL PROB.

Data retrieved from NASA's ASRS site as of July 2007 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.