Small aircraft overshoots final approach course when CDI needle sticks.

Attributes
ACN	166855
Time
Date	199012
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : hvn
State Reference	CT
Altitude	msl bound lower : 2000 msl bound upper : 2000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : n90 tower : mbpv
Operator	general aviation : instructional
Make Model Name	Small Aircraft
Flight Phase	descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : private
Experience	flight time last 90 days : 40 flight time total : 235 flight time type : 75
ASRS Report	166855
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical non adherence : clearance other spatial deviation
Independent Detector	other controllera
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

My #1 navigation radio had a CDI that stuck periodically. The problem was only discovered when on the VOR a approach into hvn. When I was being vectored to intercept the final approach course I set up the radios for the approach. At the time I did so the approach course was to my left and the needle indicated so. I was vectored to intercept at oru about a 30 degree angle. I flew this heading and the needle never moved. Atl advised me I was off course and told me to climb immediately. The conditions were VFR so I cancelled IFR and flew the approach visly. Later the avionics shop discovered that the CDI would lock to the left periodically and they were unable to diagnose why.

Original NASA ASRS Text

Title: SMA OVERSHOOTS FINAL APCH COURSE WHEN CDI NEEDLE STICKS.

Narrative: MY #1 NAV RADIO HAD A CDI THAT STUCK PERIODICALLY. THE PROB WAS ONLY DISCOVERED WHEN ON THE VOR A APCH INTO HVN. WHEN I WAS BEING VECTORED TO INTERCEPT THE FINAL APCH COURSE I SET UP THE RADIOS FOR THE APCH. AT THE TIME I DID SO THE APCH COURSE WAS TO MY L AND THE NEEDLE INDICATED SO. I WAS VECTORED TO INTERCEPT AT ORU ABOUT A 30 DEG ANGLE. I FLEW THIS HDG AND THE NEEDLE NEVER MOVED. ATL ADVISED ME I WAS OFF COURSE AND TOLD ME TO CLB IMMEDIATELY. THE CONDITIONS WERE VFR SO I CANCELLED IFR AND FLEW THE APCH VISLY. LATER THE AVIONICS SHOP DISCOVERED THAT THE CDI WOULD LOCK TO THE L PERIODICALLY AND THEY WERE UNABLE TO DIAGNOSE WHY.

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.