A B737 captain became disoriented during the transition between a HUD approach to a visual approach....

Attributes
ACN	602395
Time
Date	200312
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : stl.airport
State Reference	MO
Altitude	msl single value : 700
Environment
Flight Conditions	VMC
Weather Elements	Snow
Light	Dawn
Aircraft 1
Controlling Facilities	tower : stl.tower
Operator	common carrier : air carrier
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	descent : approach landing : go around
Route In Use	approach : visual
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tower : stl.tower
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	ground : taxi
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 11000 flight time type : 9500
ASRS Report	602395
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	other anomaly other spatial deviation
Independent Detector	other controllerb other flight crewa
Resolutory Action	controller : issued new clearance flight crew : executed go around
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

We had set up for an approach to runway 12R stl. Winds were 150 degrees at 13 KTS gusts to 23 KTS. We briefed a practice hgs (heads up guidance system), noting that we might not be able to engage aiii mode due to the crosswind. Everything was normal down to the '500 ft aiii mode call.' by the 400 ft call, we realized that the glare on the runway was an aircraft taxiing in our direction, but about to turn off. When he did, there was another aircraft behind him. At that point, we began a go around. At the same time, we got a call from tower to go around. We stayed in the pattern for a left downwind landing to runway 12L. On taxi in, we were given the tower supervisor's number to call at the gate. When I talked to the tower supervisor, I was surprised to hear that the go around was given because it appeared to them that I was lined up on taxiway a. The whole approach flashed before my eyes. How could that be? We had the ILS frequencys tuned, I was on the HUD. We had it all covered. Then doubt started sinking in. What were those aircraft doing on the 'runway?' as I write this, I still don't know for sure what I was lined up with. I followed the HUD cues down to about 300 ft where I decided to stow the HUD and concentrate on the crosswind landing ahead. If I was lined up on taxiway a, it must have happened on the switch from the HUD to all visual. Concentrating on the aircraft on the 'runway,' the crab angle and the rising sun reflecting off the snow were all factors that contributed to the potential error.

Original NASA ASRS Text

Title: A B737 CAPT BECAME DISORIENTED DURING THE TRANSITION BTWN A HUD APCH TO A VISUAL APCH. THE CAPT LINED UP WITH AN OCCUPIED TXWY RESULTING IN A GAR.

Narrative: WE HAD SET UP FOR AN APCH TO RWY 12R STL. WINDS WERE 150 DEGS AT 13 KTS GUSTS TO 23 KTS. WE BRIEFED A PRACTICE HGS (HEADS UP GUIDANCE SYS), NOTING THAT WE MIGHT NOT BE ABLE TO ENGAGE AIII MODE DUE TO THE XWIND. EVERYTHING WAS NORMAL DOWN TO THE '500 FT AIII MODE CALL.' BY THE 400 FT CALL, WE REALIZED THAT THE GLARE ON THE RWY WAS AN ACFT TAXIING IN OUR DIRECTION, BUT ABOUT TO TURN OFF. WHEN HE DID, THERE WAS ANOTHER ACFT BEHIND HIM. AT THAT POINT, WE BEGAN A GAR. AT THE SAME TIME, WE GOT A CALL FROM TWR TO GO AROUND. WE STAYED IN THE PATTERN FOR A L DOWNWIND LNDG TO RWY 12L. ON TAXI IN, WE WERE GIVEN THE TWR SUPVR'S NUMBER TO CALL AT THE GATE. WHEN I TALKED TO THE TWR SUPVR, I WAS SURPRISED TO HEAR THAT THE GAR WAS GIVEN BECAUSE IT APPEARED TO THEM THAT I WAS LINED UP ON TXWY A. THE WHOLE APCH FLASHED BEFORE MY EYES. HOW COULD THAT BE? WE HAD THE ILS FREQS TUNED, I WAS ON THE HUD. WE HAD IT ALL COVERED. THEN DOUBT STARTED SINKING IN. WHAT WERE THOSE ACFT DOING ON THE 'RWY?' AS I WRITE THIS, I STILL DON'T KNOW FOR SURE WHAT I WAS LINED UP WITH. I FOLLOWED THE HUD CUES DOWN TO ABOUT 300 FT WHERE I DECIDED TO STOW THE HUD AND CONCENTRATE ON THE XWIND LNDG AHEAD. IF I WAS LINED UP ON TXWY A, IT MUST HAVE HAPPENED ON THE SWITCH FROM THE HUD TO ALL VISUAL. CONCENTRATING ON THE ACFT ON THE 'RWY,' THE CRAB ANGLE AND THE RISING SUN REFLECTING OFF THE SNOW WERE ALL FACTORS THAT CONTRIBUTED TO THE POTENTIAL 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.

A B737 captain became disoriented during the transition between a HUD approach to a visual approach. The captain lined up with an occupied taxiway resulting in a go around.