Omega navigation fault took aircraft off course.

Attributes
ACN	302972
Time
Date	199504
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ord
State Reference	IL
Aircraft 1
Controlling Facilities	artcc : zau
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	302972
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
ASRS Report	303081
Events
Anomaly	non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Climbing out from ord, center cleared us direct to tth. Autoplt is on track change to tth on omega. Engaged navigation track, aircraft is now tracking to tth. Checked navigation display about 2 mins later and noticed that aircraft has turned to somewhere around 120 degree heading. Omega is no longer tracking on course, even though FMA still says navigation track. Center asked to turn right, back on course. Don't know if there was a conflict.

Original NASA ASRS Text

Title: OMEGA NAV FAULT TOOK ACFT OFF COURSE.

Narrative: CLBING OUT FROM ORD, CTR CLRED US DIRECT TO TTH. AUTOPLT IS ON TRACK CHANGE TO TTH ON OMEGA. ENGAGED NAV TRACK, ACFT IS NOW TRACKING TO TTH. CHKED NAV DISPLAY ABOUT 2 MINS LATER AND NOTICED THAT ACFT HAS TURNED TO SOMEWHERE AROUND 120 DEG HDG. OMEGA IS NO LONGER TRACKING ON COURSE, EVEN THOUGH FMA STILL SAYS NAV TRACK. CTR ASKED TO TURN R, BACK ON COURSE. DON'T KNOW IF THERE WAS A CONFLICT.

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.