Small aircraft on practice ILS approach has sticky CDI, overshoots localizer intercept into parallel...

Attributes
ACN	263879
Time
Date	199402
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : hnl
State Reference	HI
Altitude	msl bound lower : 1500 msl bound upper : 1500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : hnl
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : cfi pilot : commercial
Experience	flight time last 90 days : 25 flight time total : 607 flight time type : 500
ASRS Report	263879
Person 2
Affiliation	Other
Function	other personnel other
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical non adherence : clearance other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : became reoriented other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

We were cleared for a practice approach for the ILS runway 4R and given an intercept course by the approach controller to the localizer. I was under the hood and my safety pilot was looking for traffic. As I continued to monitor the CDI, I noticed the GS was starting to move but not the CDI. The CDI needle was pegged to the left. About a min later, it occurred to me that something may be wrong with the CDI. I took off the IFR hood and saw that I had passed well through the localizer and into the parallel runway's approach path. I immediately turned the aircraft back to the localizer course. Then I 'tapped' the VOR display at which time the CDI became unstuck and immediately swung over to the right side (as it should). It appeared that the CDI was stuck to the left and the tapping on the glass freed it to move and register properly. The 'sticky' CDI may have been the result of moisture in the instrument. There was no conflict in traffic. We landed safely. I called the hnl tower on the telephone and explained the situation. They indicated that there was no problem.

Original NASA ASRS Text

Title: SMA ON PRACTICE ILS APCH HAS STICKY CDI, OVERSHOOTS LOC INTERCEPT INTO PARALLEL RWY APCH PATH.

Narrative: WE WERE CLRED FOR A PRACTICE APCH FOR THE ILS RWY 4R AND GIVEN AN INTERCEPT COURSE BY THE APCH CTLR TO THE LOC. I WAS UNDER THE HOOD AND MY SAFETY PLT WAS LOOKING FOR TFC. AS I CONTINUED TO MONITOR THE CDI, I NOTICED THE GS WAS STARTING TO MOVE BUT NOT THE CDI. THE CDI NEEDLE WAS PEGGED TO THE L. ABOUT A MIN LATER, IT OCCURRED TO ME THAT SOMETHING MAY BE WRONG WITH THE CDI. I TOOK OFF THE IFR HOOD AND SAW THAT I HAD PASSED WELL THROUGH THE LOC AND INTO THE PARALLEL RWY'S APCH PATH. I IMMEDIATELY TURNED THE ACFT BACK TO THE LOC COURSE. THEN I 'TAPPED' THE VOR DISPLAY AT WHICH TIME THE CDI BECAME UNSTUCK AND IMMEDIATELY SWUNG OVER TO THE R SIDE (AS IT SHOULD). IT APPEARED THAT THE CDI WAS STUCK TO THE L AND THE TAPPING ON THE GLASS FREED IT TO MOVE AND REGISTER PROPERLY. THE 'STICKY' CDI MAY HAVE BEEN THE RESULT OF MOISTURE IN THE INST. THERE WAS NO CONFLICT IN TFC. WE LANDED SAFELY. I CALLED THE HNL TWR ON THE TELEPHONE AND EXPLAINED THE SIT. THEY INDICATED THAT THERE WAS NO PROB.

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.

Small aircraft on practice ILS approach has sticky CDI, overshoots localizer intercept into parallel runway approach path.