Narrative:

We were departing/landing to the east. The WX was cavu. I had just relieved the local controller maybe 2-3 mins prior to when the pilot asked about the aircraft that he apparently just passed over. By the sound of his voice, it was obviously within an uncomfortable proximity. There were only 2 aircraft on final at the time. Both had already been cleared to land by the controller I had just relieved. There were no departing aircraft ready for takeoff. Traffic survey (media broadcast traffic reporting) aircraft were flying their normal flight paths. In this case, where they cross our final, they are outside the final approach fix, and 500 ft below the outer ring of our class C airspace. The pilot of aircraft X, a paye, who was inbound for runway 10R said something like 'who was that who just passed 300 ft below me?' at that time he was just outside the FAF (arlig), on a visual approach. The runway 10R GS was OTS. Normally aircraft on a visual approach will stay at or above the glide path, and are therefore at least 700 ft above the standard flight pattern of the traffic survey aircraft. However, in this case, the pilot of aircraft X was well below the normal flight path, and that put him below the lower limit of the outer ring of our class C airspace (2500 ft MSL). He was at 2300 ft MSL when typically he would've been at or above 2700 ft MSL. The traffic survey aircraft fly at 2000 ft MSL. I hadn't considered the implications of the GS being OTS. I was not expecting the pilot to be so low. I do not recall hearing any conflict alert audible alarm. I believe that had I heard a conflict alarm activate, that would have certainly brought my attention to the situation. There was 1 other controller (working ground control), and a supervisor (working clearance delivery) in the cabin attendant. Had they observed the situation (especially if conflict alert was blaring), I firmly believe they would have said something. My inability to see the entire airport movement area was a primary distraction for me. I didn't observe any corrective action taken by the pilot, nor did the pilot advise of any corrective action. Factors affecting the quality of human performance: I am unable to observe vast expanses of the airport movement area while standing in any one location in the tower cabin attendant. To be able to see adequately, I utilize a 14

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Original NASA ASRS Text

Title: CMH LCL CTLR FAILS TO ISSUE TFC RESULTING IN TFC CONFLICT.

Narrative: WE WERE DEPARTING/LNDG TO THE E. THE WX WAS CAVU. I HAD JUST RELIEVED THE LCL CTLR MAYBE 2-3 MINS PRIOR TO WHEN THE PLT ASKED ABOUT THE ACFT THAT HE APPARENTLY JUST PASSED OVER. BY THE SOUND OF HIS VOICE, IT WAS OBVIOUSLY WITHIN AN UNCOMFORTABLE PROX. THERE WERE ONLY 2 ACFT ON FINAL AT THE TIME. BOTH HAD ALREADY BEEN CLRED TO LAND BY THE CTLR I HAD JUST RELIEVED. THERE WERE NO DEPARTING ACFT READY FOR TKOF. TFC SURVEY (MEDIA BROADCAST TFC RPTING) ACFT WERE FLYING THEIR NORMAL FLT PATHS. IN THIS CASE, WHERE THEY CROSS OUR FINAL, THEY ARE OUTSIDE THE FINAL APCH FIX, AND 500 FT BELOW THE OUTER RING OF OUR CLASS C AIRSPACE. THE PLT OF ACFT X, A PAYE, WHO WAS INBOUND FOR RWY 10R SAID SOMETHING LIKE 'WHO WAS THAT WHO JUST PASSED 300 FT BELOW ME?' AT THAT TIME HE WAS JUST OUTSIDE THE FAF (ARLIG), ON A VISUAL APCH. THE RWY 10R GS WAS OTS. NORMALLY ACFT ON A VISUAL APCH WILL STAY AT OR ABOVE THE GLIDE PATH, AND ARE THEREFORE AT LEAST 700 FT ABOVE THE STANDARD FLT PATTERN OF THE TFC SURVEY ACFT. HOWEVER, IN THIS CASE, THE PLT OF ACFT X WAS WELL BELOW THE NORMAL FLT PATH, AND THAT PUT HIM BELOW THE LOWER LIMIT OF THE OUTER RING OF OUR CLASS C AIRSPACE (2500 FT MSL). HE WAS AT 2300 FT MSL WHEN TYPICALLY HE WOULD'VE BEEN AT OR ABOVE 2700 FT MSL. THE TFC SURVEY ACFT FLY AT 2000 FT MSL. I HADN'T CONSIDERED THE IMPLICATIONS OF THE GS BEING OTS. I WAS NOT EXPECTING THE PLT TO BE SO LOW. I DO NOT RECALL HEARING ANY CONFLICT ALERT AUDIBLE ALARM. I BELIEVE THAT HAD I HEARD A CONFLICT ALARM ACTIVATE, THAT WOULD HAVE CERTAINLY BROUGHT MY ATTN TO THE SIT. THERE WAS 1 OTHER CTLR (WORKING GND CTL), AND A SUPVR (WORKING CLRNC DELIVERY) IN THE CAB. HAD THEY OBSERVED THE SIT (ESPECIALLY IF CONFLICT ALERT WAS BLARING), I FIRMLY BELIEVE THEY WOULD HAVE SAID SOMETHING. MY INABILITY TO SEE THE ENTIRE ARPT MOVEMENT AREA WAS A PRIMARY DISTR FOR ME. I DIDN'T OBSERVE ANY CORRECTIVE ACTION TAKEN BY THE PLT, NOR DID THE PLT ADVISE OF ANY CORRECTIVE ACTION. FACTORS AFFECTING THE QUALITY OF HUMAN PERFORMANCE: I AM UNABLE TO OBSERVE VAST EXPANSES OF THE ARPT MOVEMENT AREA WHILE STANDING IN ANY ONE LOCATION IN THE TWR CAB. TO BE ABLE TO SEE ADEQUATELY, I UTILIZE A 14

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.