Narrative:

During ILS approach, with both autoplt's connected (coupled), several unusual events were observed. 1) the aircraft yawed noticeably for no apparent reason. 2) the autoland fail light illuminated (1500 ft) even though it should never come on above 200 ft. 3) autoplt #1 disconnected, which is not normal, even for autoland fail. 4) I recall seeing a momentary ECAM message about thrust reversers. I took the aircraft and landed normally. Maintenance inspected thrust reversers -- no fault noted. After some discussion, the write-up was signed off. I refused the aircraft due to lack of resolution of the uncommanded yaw and autoland light at inappropriate altitude. A later review of maintenance records showed unresolved issues with radio altimeters #1 and #2, rudder limiter, thrust reverser. Readout from flight data recorder indicates 5 degree rudder displacement (uncommanded). Callback conversation with reporter revealed the following information: reporter indicated that the ECAM thrust reverser indication was momentary and there were none of the normal reverse indications displayed. The yaw was felt and the flight data recorder indicated uncommanded rudder displacement at the time of the incident. The aircraft was held over for maintenance for 6 hours and the company union and manufacturer are looking into the incident. Reporter has flown the aircraft since. There has been a left engine change and no further problems in the log history that he has access to.

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Original NASA ASRS Text

Title: AIRBUS EXPERIENCES UNCOMMANDED YAW ON COUPLED APCH TO MSP, MN.

Narrative: DURING ILS APCH, WITH BOTH AUTOPLT'S CONNECTED (COUPLED), SEVERAL UNUSUAL EVENTS WERE OBSERVED. 1) THE ACFT YAWED NOTICEABLY FOR NO APPARENT REASON. 2) THE AUTOLAND FAIL LIGHT ILLUMINATED (1500 FT) EVEN THOUGH IT SHOULD NEVER COME ON ABOVE 200 FT. 3) AUTOPLT #1 DISCONNECTED, WHICH IS NOT NORMAL, EVEN FOR AUTOLAND FAIL. 4) I RECALL SEEING A MOMENTARY ECAM MESSAGE ABOUT THRUST REVERSERS. I TOOK THE ACFT AND LANDED NORMALLY. MAINT INSPECTED THRUST REVERSERS -- NO FAULT NOTED. AFTER SOME DISCUSSION, THE WRITE-UP WAS SIGNED OFF. I REFUSED THE ACFT DUE TO LACK OF RESOLUTION OF THE UNCOMMANDED YAW AND AUTOLAND LIGHT AT INAPPROPRIATE ALT. A LATER REVIEW OF MAINT RECORDS SHOWED UNRESOLVED ISSUES WITH RADIO ALTIMETERS #1 AND #2, RUDDER LIMITER, THRUST REVERSER. READOUT FROM FLT DATA RECORDER INDICATES 5 DEG RUDDER DISPLACEMENT (UNCOMMANDED). CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR INDICATED THAT THE ECAM THRUST REVERSER INDICATION WAS MOMENTARY AND THERE WERE NONE OF THE NORMAL REVERSE INDICATIONS DISPLAYED. THE YAW WAS FELT AND THE FLT DATA RECORDER INDICATED UNCOMMANDED RUDDER DISPLACEMENT AT THE TIME OF THE INCIDENT. THE ACFT WAS HELD OVER FOR MAINT FOR 6 HRS AND THE COMPANY UNION AND MANUFACTURER ARE LOOKING INTO THE INCIDENT. RPTR HAS FLOWN THE ACFT SINCE. THERE HAS BEEN A L ENG CHANGE AND NO FURTHER PROBS IN THE LOG HISTORY THAT HE HAS ACCESS TO.

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.