ILS approach lines up with taxiway lands runway.

Attributes
ACN	193108
Time
Date	199110
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : mem
State Reference	TN
Altitude	agl bound lower : 400 agl bound upper : 400
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : mem tower : mem tower : ric
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : cfi pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 190 flight time total : 4500 flight time type : 925
ASRS Report	193108
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

The aircraft was on ILS approach to airport. At approximately 400 ft AGL, instrument compare warning illuminated, and flags appeared on localizer and GS indication. At this point both pilots had the runway in sight, however visibility was low with fog. The distraction of the instrument warning and unreliable localizer and GS indication caused both pilots to focus their attention inside the cockpit for a few seconds. When this occurred there was a small amount of confusion and discussion between the pilots. When the pilots looked outside again, there appeared to be an aircraft on the runway. This was actually an aircraft on a taxiway. The aircraft was now lined up with a taxiway, instead of the active runway. The tower issued a warning and the crew then spotted the runway. The aircraft was still in position for a normal landing, requiring a small left correction. The confusion created by the cockpit indications allowed the pilot to let aircraft heading wander slightly to the right. Low visibility (reported by tower at 4 mi) prevented immediate detection of flight crew error.

Original NASA ASRS Text

Title: ILS APCH LINES UP WITH TAXIWAY LANDS RWY.

Narrative: THE ACFT WAS ON ILS APCH TO ARPT. AT APPROX 400 FT AGL, INST COMPARE WARNING ILLUMINATED, AND FLAGS APPEARED ON LOC AND GS INDICATION. AT THIS POINT BOTH PLTS HAD THE RWY IN SIGHT, HOWEVER VISIBILITY WAS LOW WITH FOG. THE DISTR OF THE INST WARNING AND UNRELIABLE LOC AND GS INDICATION CAUSED BOTH PLTS TO FOCUS THEIR ATTN INSIDE THE COCKPIT FOR A FEW SECONDS. WHEN THIS OCCURRED THERE WAS A SMALL AMOUNT OF CONFUSION AND DISCUSSION BTWN THE PLTS. WHEN THE PLTS LOOKED OUTSIDE AGAIN, THERE APPEARED TO BE AN ACFT ON THE RWY. THIS WAS ACTUALLY AN ACFT ON A TAXIWAY. THE ACFT WAS NOW LINED UP WITH A TAXIWAY, INSTEAD OF THE ACTIVE RWY. THE TWR ISSUED A WARNING AND THE CREW THEN SPOTTED THE RWY. THE ACFT WAS STILL IN POS FOR A NORMAL LNDG, REQUIRING A SMALL L CORRECTION. THE CONFUSION CREATED BY THE COCKPIT INDICATIONS ALLOWED THE PLT TO LET ACFT HDG WANDER SLIGHTLY TO THE R. LOW VISIBILITY (RPTED BY TWR AT 4 MI) PREVENTED IMMEDIATE DETECTION OF FLC ERROR.

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.