The ADF did not work properly on an NDB approach.

Attributes
ACN	249341
Time
Date	199308
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ord
State Reference	IL
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ord
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent : approach ground : preflight
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 215 flight time total : 9000 flight time type : 3000
ASRS Report	249341
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : less severe non adherence : published procedure other anomaly other other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Cleared to intercept NDB final runway 9R at ord. ADF had been pointing properly and idented normally. Needle swung to indicate station was at 12 O'clock position which we knew to be incorrect. Couldn't get a word in to approach control before she realized we were going through final and gave us a turn back toward the LOM. Needle started pointing correctly after station passage. A visual on the airport was picked up in time to make a normal landing.

Original NASA ASRS Text

Title: THE ADF DID NOT WORK PROPERLY ON AN NDB APCH.

Narrative: CLRED TO INTERCEPT NDB FINAL RWY 9R AT ORD. ADF HAD BEEN POINTING PROPERLY AND IDENTED NORMALLY. NEEDLE SWUNG TO INDICATE STATION WAS AT 12 O'CLOCK POS WHICH WE KNEW TO BE INCORRECT. COULDN'T GET A WORD IN TO APCH CTL BEFORE SHE REALIZED WE WERE GOING THROUGH FINAL AND GAVE US A TURN BACK TOWARD THE LOM. NEEDLE STARTED POINTING CORRECTLY AFTER STATION PASSAGE. A VISUAL ON THE ARPT WAS PICKED UP IN TIME TO MAKE A NORMAL LNDG.

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.