Narrative:

On ILS final approach to 18L at memphis, we had the runway in sight at about 1000 ft AGL. Drifting fog, clouds, and light rain made keeping the runway in sight at all times doubtful, so I told the copilot that I would stay on the gauges. At about 500 ft AGL, 2 red lights came on on my instrument comparator, as well as the copilot's comparator. Our attention was immediately drawn to the red lights and then to the ILS raw data. About the time we had concluded that we had no course or GS guidance, tower advised that they had ILS warnings and if we did not have the runway in sight to go around. Looking up, we were exactly lined up with the parallel taxiway just to the right of the runway. We had been told to expect one departure prior to our arrival, and sitting right in the middle of the taxiway was an airplane, as if in takeoff position. Thinking we were still lined up with the runway, we called runway in sight and were cleared to land. Our attention was completely concentrated on the aircraft ahead of us since he did not appear to be rolling. As I prepared mentally for a go around I told the copilot to advise the tower of the airplane on the runway. Although concentrating on the airplane on the ground, the whole picture felt wrong to me. When the tower responded that there was no airplane on the runway, I immediately realized what was wrong with the picture, looked slightly left and saw the runway in full view. Tower told us to go around. But we advised the runway in sight and they cleared us to land. We were above 200 ft AGL and a smooth transition and landing was made. Low visibility combined with the distraction of an 'aircraft on the runway' kept us from seeing the runway when we first went visual. Localizer failure and red lights in the cockpit at a very inopportune time caused us to drift slightly right as we analyzed the situation. Having the runway dimly in sight at 1000 ft AGL, and expecting a departure prior to our arrival, contributed to our confusion. The deck was stacked against us, but an accident was not about to happen as nothing felt right about what we were seeing and we were just about to go around for another try.

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Original NASA ASRS Text

Title: ARPT PROBLEM ILS CREATES A PROBLEM FOR ACR FLC IN HDG TRACK DEV THAT NEARLY RESULTED IN ACFT LNDG ON TAXIWAY.

Narrative: ON ILS FINAL APCH TO 18L AT MEMPHIS, WE HAD THE RWY IN SIGHT AT ABOUT 1000 FT AGL. DRIFTING FOG, CLOUDS, AND LIGHT RAIN MADE KEEPING THE RWY IN SIGHT AT ALL TIMES DOUBTFUL, SO I TOLD THE COPLT THAT I WOULD STAY ON THE GAUGES. AT ABOUT 500 FT AGL, 2 RED LIGHTS CAME ON ON MY INST COMPARATOR, AS WELL AS THE COPLT'S COMPARATOR. OUR ATTN WAS IMMEDIATELY DRAWN TO THE RED LIGHTS AND THEN TO THE ILS RAW DATA. ABOUT THE TIME WE HAD CONCLUDED THAT WE HAD NO COURSE OR GS GUIDANCE, TWR ADVISED THAT THEY HAD ILS WARNINGS AND IF WE DID NOT HAVE THE RWY IN SIGHT TO GAR. LOOKING UP, WE WERE EXACTLY LINED UP WITH THE PARALLEL TAXIWAY JUST TO THE R OF THE RWY. WE HAD BEEN TOLD TO EXPECT ONE DEP PRIOR TO OUR ARR, AND SITTING RIGHT IN THE MIDDLE OF THE TAXIWAY WAS AN AIRPLANE, AS IF IN TKOF POS. THINKING WE WERE STILL LINED UP WITH THE RWY, WE CALLED RWY IN SIGHT AND WERE CLRED TO LAND. OUR ATTN WAS COMPLETELY CONCENTRATED ON THE ACFT AHEAD OF US SINCE HE DID NOT APPEAR TO BE ROLLING. AS I PREPARED MENTALLY FOR A GAR I TOLD THE COPLT TO ADVISE THE TWR OF THE AIRPLANE ON THE RWY. ALTHOUGH CONCENTRATING ON THE AIRPLANE ON THE GND, THE WHOLE PICTURE FELT WRONG TO ME. WHEN THE TWR RESPONDED THAT THERE WAS NO AIRPLANE ON THE RWY, I IMMEDIATELY REALIZED WHAT WAS WRONG WITH THE PICTURE, LOOKED SLIGHTLY L AND SAW THE RWY IN FULL VIEW. TWR TOLD US TO GAR. BUT WE ADVISED THE RWY IN SIGHT AND THEY CLRED US TO LAND. WE WERE ABOVE 200 FT AGL AND A SMOOTH TRANSITION AND LNDG WAS MADE. LOW VISIBILITY COMBINED WITH THE DISTR OF AN 'ACFT ON THE RWY' KEPT US FROM SEEING THE RWY WHEN WE FIRST WENT VISUAL. LOC FAILURE AND RED LIGHTS IN THE COCKPIT AT A VERY INOPPORTUNE TIME CAUSED US TO DRIFT SLIGHTLY R AS WE ANALYZED THE SITUATION. HAVING THE RWY DIMLY IN SIGHT AT 1000 FT AGL, AND EXPECTING A DEP PRIOR TO OUR ARR, CONTRIBUTED TO OUR CONFUSION. THE DECK WAS STACKED AGAINST US, BUT AN ACCIDENT WAS NOT ABOUT TO HAPPEN AS NOTHING FELT RIGHT ABOUT WHAT WE WERE SEEING AND WE WERE JUST ABOUT TO GAR FOR ANOTHER TRY.

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.