Air carrier off centerline on localizer due equipment problem. Go around.

Attributes
ACN	179729
Time
Date	199105
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : dfw
State Reference	TX
Altitude	msl bound lower : 3000 msl bound upper : 4000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dfw tracon : fay
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 9000
ASRS Report	179729
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe non adherence : clearance other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

When cleared to intercept 17R localizer at dfw at 4000' and approaching localizer capture, first officer's instruments showed a further right turn for intercept while captain's showed on centerline. First officer followed his indications and consequently found that the aircraft was right of course. Approach control notified us of deviation and suggested a 150 degree heading to reintercept. First officer went to 150 degree heading for correct and told captain of his situation. Captain's instruments seemed to be ok, but annunciations on upper panel were inconsistent with normal procedure. Our s-turn caused a spacing problem for ATC, so we took vectors for another approach, still trying to figure out our problem. Upon reintercepting 17R localizer using captain's instruments, first officer instruments were found to be grossly inaccurate, and moments later started to flash intermittently. Approach and landing were made west/O further problems. Wrote up faulty indications. This all occurred at the worst time possible for a 2-M crew. A high workload and faulty instruments failing at the wrong time created a situation that could have had substantial consequences.

Original NASA ASRS Text

Title: ACR OFF CENTERLINE ON LOCALIZER DUE EQUIPMENT PROBLEM. GO AROUND.

Narrative: WHEN CLRED TO INTERCEPT 17R LOC AT DFW AT 4000' AND APCHING LOC CAPTURE, F/O'S INSTRUMENTS SHOWED A FURTHER RIGHT TURN FOR INTERCEPT WHILE CAPT'S SHOWED ON CENTERLINE. F/O FOLLOWED HIS INDICATIONS AND CONSEQUENTLY FOUND THAT THE ACFT WAS RIGHT OF COURSE. APCH CTL NOTIFIED US OF DEVIATION AND SUGGESTED A 150 DEG HDG TO REINTERCEPT. F/O WENT TO 150 DEG HDG FOR CORRECT AND TOLD CAPT OF HIS SITUATION. CAPT'S INSTRUMENTS SEEMED TO BE OK, BUT ANNUNCIATIONS ON UPPER PANEL WERE INCONSISTENT WITH NORMAL PROC. OUR S-TURN CAUSED A SPACING PROB FOR ATC, SO WE TOOK VECTORS FOR ANOTHER APCH, STILL TRYING TO FIGURE OUT OUR PROB. UPON REINTERCEPTING 17R LOC USING CAPT'S INSTRUMENTS, F/O INSTRUMENTS WERE FOUND TO BE GROSSLY INACCURATE, AND MOMENTS LATER STARTED TO FLASH INTERMITTENTLY. APCH AND LNDG WERE MADE W/O FURTHER PROBS. WROTE UP FAULTY INDICATIONS. THIS ALL OCCURRED AT THE WORST TIME POSSIBLE FOR A 2-M CREW. A HIGH WORKLOAD AND FAULTY INSTRUMENTS FAILING AT THE WRONG TIME CREATED A SITUATION THAT COULD HAVE HAD SUBSTANTIAL CONSEQUENCES.

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.