CL65 crew had conflicting and erratic localizer indications for runway 31L at jfk.

Attributes
ACN	573140
Time
Date	200302
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : jfk.airport
State Reference	NY
Altitude	msl single value : 2000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tower : jfk.tower
Operator	common carrier : air carrier
Make Model Name	Regional Jet CL65, Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 31l
Flight Phase	descent : approach
Route In Use	approach : instrument precision
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 240 flight time total : 3600 flight time type : 2000
ASRS Report	573140
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	inflight encounter : weather other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : loc course indication nd magenta line other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance flight crew : executed missed approach other
Consequence	other
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance Airport Aircraft Navigational Facility
Primary Problem	Navigational Facility

Narrative:

Air carrier X flight was cleared for the approach on runway 31L at jfk. Both pilots had the radios set with the ILS frequency 111.35 and the approach mode was selected. We were on a heading to intercept the approach. The localizer showed a full deflection but the FMS was showing captured. The airplane then started a turn to the right (the wrong direction for the approach). The autoplt was immediately disconnected and I turned the airplane back on course for the ILS. We proceeded down towards the runway and at about 1000 ft we received a full left then a full right deflection on the localizer. We executed a missed approach. The tower vectored us around for another approach. At about 800 ft we got a visual on the runway. The localizer then showed a deflection to the right even though we were aligned with the runway. We landed without incident. Maintenance was called out to work on the avionics.

Original NASA ASRS Text

Title: CL65 CREW HAD CONFLICTING AND ERRATIC LOC INDICATIONS FOR RWY 31L AT JFK.

Narrative: ACR X FLT WAS CLRED FOR THE APCH ON RWY 31L AT JFK. BOTH PLTS HAD THE RADIOS SET WITH THE ILS FREQ 111.35 AND THE APCH MODE WAS SELECTED. WE WERE ON A HDG TO INTERCEPT THE APCH. THE LOC SHOWED A FULL DEFLECTION BUT THE FMS WAS SHOWING CAPTURED. THE AIRPLANE THEN STARTED A TURN TO THE R (THE WRONG DIRECTION FOR THE APCH). THE AUTOPLT WAS IMMEDIATELY DISCONNECTED AND I TURNED THE AIRPLANE BACK ON COURSE FOR THE ILS. WE PROCEEDED DOWN TOWARDS THE RWY AND AT ABOUT 1000 FT WE RECEIVED A FULL L THEN A FULL R DEFLECTION ON THE LOC. WE EXECUTED A MISSED APCH. THE TWR VECTORED US AROUND FOR ANOTHER APCH. AT ABOUT 800 FT WE GOT A VISUAL ON THE RWY. THE LOC THEN SHOWED A DEFLECTION TO THE R EVEN THOUGH WE WERE ALIGNED WITH THE RWY. WE LANDED WITHOUT INCIDENT. MAINT WAS CALLED OUT TO WORK ON THE AVIONICS.

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.