B737 captain reports that the localizer course for runway 10 at ord appears to be off by 3 degrees. 090 degrees appears to be the correct localizer course and runway heading.

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Attributes
ACN	755098
Time
Date	200709
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : ord.airport
State Reference	IL
Altitude	agl single value : 1500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : c90.tracon
Operator	common carrier : air carrier
Make Model Name	B737-500
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer only : 10 other
Flight Phase	descent : approach
Route In Use	approach : instrument non precision
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 190 flight time total : 10000 flight time type : 5500
ASRS Report	755098
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Supplementary
Problem Areas	Airport Chart Or Publication Aircraft
Primary Problem	Ambiguous

Narrative:

While flying the localizer approach to runway 10 ord; the page for the ILS or localizer runway 10 shows a final approach course of 093 degrees. Both captain and first officer had 093 degrees in the obs; 'man/exp' selected for the HSI. The CDI was centered and the track was showing 3 degrees off from the course line for the entire approach. The winds were calm. During rollout; the track and course were still not overlayed. The track was indicating straight up (090 degrees) while tracking runway centerline during rollout while the course was still 3 degrees off. If the CDI remains centered up; the track line will be overlayed with the course line. The track information appeared to be accurate as confirmed with visual indications while lined up with the runway in zero wind conditions. I have doubts as to the accuracy of the final approach course that is published.

Original NASA ASRS Text

Title: B737 CAPTAIN REPORTS THAT THE LOC COURSE FOR RWY 10 AT ORD APPEARS TO BE OFF BY 3 DEGREES. 090 DEGREES APPEARS TO BE THE CORRECT LOC COURSE AND RWY HEADING.

Narrative: WHILE FLYING THE LOC APCH TO RWY 10 ORD; THE PAGE FOR THE ILS OR LOC RWY 10 SHOWS A FINAL APCH COURSE OF 093 DEGS. BOTH CAPT AND FO HAD 093 DEGS IN THE OBS; 'MAN/EXP' SELECTED FOR THE HSI. THE CDI WAS CTRED AND THE TRACK WAS SHOWING 3 DEGS OFF FROM THE COURSE LINE FOR THE ENTIRE APCH. THE WINDS WERE CALM. DURING ROLLOUT; THE TRACK AND COURSE WERE STILL NOT OVERLAYED. THE TRACK WAS INDICATING STRAIGHT UP (090 DEGS) WHILE TRACKING RWY CTRLINE DURING ROLLOUT WHILE THE COURSE WAS STILL 3 DEGS OFF. IF THE CDI REMAINS CTRED UP; THE TRACK LINE WILL BE OVERLAYED WITH THE COURSE LINE. THE TRACK INFO APPEARED TO BE ACCURATE AS CONFIRMED WITH VISUAL INDICATIONS WHILE LINED UP WITH THE RWY IN ZERO WIND CONDITIONS. I HAVE DOUBTS AS TO THE ACCURACY OF THE FINAL APCH COURSE THAT IS PUBLISHED.

Data retrieved from NASA's ASRS site as of January 2009 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.