Narrative:

We were cleared for the 'civet 4' profile descent and passing 'arnes' were cleared for a runway 25L ILS approach. Because the WX was so nice, I elected to do a fully coupled autoland approach. The aircraft was on GS and glidepath and all 3 autoplts armed from approximately 8000 ft on down. At 1500 ft radar altitude (shortly after) the autoland status display indicated 'land 3' and maintained 'land 3' throughout the approach. The 'flare' and 'rollout' modes also armed. The 'flare' mode engaged at the normal altitude and the 'rollout' mode did likewise. Up to this point, all autoland functions/indications were normal with the aircraft (wired) on GS and glidepath. Right after my copilot announced 'rollout' engaged, the aircraft proceeded to give an (estimated) 5 degree left wing down condition. While not alarming, it concerned me because: 1) the wind was from 330/5 KTS, and 2) during an autoland, a wings level condition is supposed to be maintained. The left main touched down first with the aircraft about 2-3 ft left of but tracking centerline. Almost immediately following left main touchdown, I got a strong right rudder input. Up until this time I had felt no unusual rudder inputs as I had been lightly backing up all controls throughout the approach and landing. The rate of rudder input was strong enough to swing the nose across the centerline and I responded by immediately disconnecting the autoplts with the yoke disconnect and applying left rudder. The touchdown and rollout were fairly normal and safe but could have been of real concern in low minimum conditions and/or with slick runway conditions. During the flare both throttles retarded normally and evenly. I did not have the autobrakes armed for the landing. Both the copilot and myself did not observe any traffic crossing the runway or taxiing parallel to the runway (either 25L or 25R) during the approach. One light twin landed ahead of (5 1/2 mi) our aircraft on 25L but had cleared both runways sometime before our landing. Callback conversation with reporter revealed the following information: reporter described the 'strong' rudder input as similar to the input you would use if an engine failed on takeoff. He said maintenance inoperative'd the #1 and #3 autoplts as a result of the incident but, while taxiing out for their next takeoff, they were told to return to the gate where the aircraft was 'impounded' and the flight data recorder was removed for study. They were given another aircraft for their trip continuation. He was criticized for not advising approach control of his intent to conduct a CAT III autoland approach.

Related reports:

Google
 

Original NASA ASRS Text

Title: ADVANCED LGT EXPERIENCES UNWANTED RUDDER INPUT AND SWERVES DURING ROLLOUT AFTER A CAT III AUTOLAND APCH AND LNDG.

Narrative: WE WERE CLRED FOR THE 'CIVET 4' PROFILE DSCNT AND PASSING 'ARNES' WERE CLRED FOR A RWY 25L ILS APCH. BECAUSE THE WX WAS SO NICE, I ELECTED TO DO A FULLY COUPLED AUTOLAND APCH. THE ACFT WAS ON GS AND GLIDEPATH AND ALL 3 AUTOPLTS ARMED FROM APPROX 8000 FT ON DOWN. AT 1500 FT RADAR ALT (SHORTLY AFTER) THE AUTOLAND STATUS DISPLAY INDICATED 'LAND 3' AND MAINTAINED 'LAND 3' THROUGHOUT THE APCH. THE 'FLARE' AND 'ROLLOUT' MODES ALSO ARMED. THE 'FLARE' MODE ENGAGED AT THE NORMAL ALT AND THE 'ROLLOUT' MODE DID LIKEWISE. UP TO THIS POINT, ALL AUTOLAND FUNCTIONS/INDICATIONS WERE NORMAL WITH THE ACFT (WIRED) ON GS AND GLIDEPATH. RIGHT AFTER MY COPLT ANNOUNCED 'ROLLOUT' ENGAGED, THE ACFT PROCEEDED TO GIVE AN (ESTIMATED) 5 DEG L WING DOWN CONDITION. WHILE NOT ALARMING, IT CONCERNED ME BECAUSE: 1) THE WIND WAS FROM 330/5 KTS, AND 2) DURING AN AUTOLAND, A WINGS LEVEL CONDITION IS SUPPOSED TO BE MAINTAINED. THE L MAIN TOUCHED DOWN FIRST WITH THE ACFT ABOUT 2-3 FT L OF BUT TRACKING CTRLINE. ALMOST IMMEDIATELY FOLLOWING L MAIN TOUCHDOWN, I GOT A STRONG R RUDDER INPUT. UP UNTIL THIS TIME I HAD FELT NO UNUSUAL RUDDER INPUTS AS I HAD BEEN LIGHTLY BACKING UP ALL CTLS THROUGHOUT THE APCH AND LNDG. THE RATE OF RUDDER INPUT WAS STRONG ENOUGH TO SWING THE NOSE ACROSS THE CTRLINE AND I RESPONDED BY IMMEDIATELY DISCONNECTING THE AUTOPLTS WITH THE YOKE DISCONNECT AND APPLYING L RUDDER. THE TOUCHDOWN AND ROLLOUT WERE FAIRLY NORMAL AND SAFE BUT COULD HAVE BEEN OF REAL CONCERN IN LOW MINIMUM CONDITIONS AND/OR WITH SLICK RWY CONDITIONS. DURING THE FLARE BOTH THROTTLES RETARDED NORMALLY AND EVENLY. I DID NOT HAVE THE AUTOBRAKES ARMED FOR THE LNDG. BOTH THE COPLT AND MYSELF DID NOT OBSERVE ANY TFC XING THE RWY OR TAXIING PARALLEL TO THE RWY (EITHER 25L OR 25R) DURING THE APCH. ONE LIGHT TWIN LANDED AHEAD OF (5 1/2 MI) OUR ACFT ON 25L BUT HAD CLRED BOTH RWYS SOMETIME BEFORE OUR LNDG. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR DESCRIBED THE 'STRONG' RUDDER INPUT AS SIMILAR TO THE INPUT YOU WOULD USE IF AN ENG FAILED ON TKOF. HE SAID MAINT INOP'D THE #1 AND #3 AUTOPLTS AS A RESULT OF THE INCIDENT BUT, WHILE TAXIING OUT FOR THEIR NEXT TKOF, THEY WERE TOLD TO RETURN TO THE GATE WHERE THE ACFT WAS 'IMPOUNDED' AND THE FLT DATA RECORDER WAS REMOVED FOR STUDY. THEY WERE GIVEN ANOTHER ACFT FOR THEIR TRIP CONTINUATION. HE WAS CRITICIZED FOR NOT ADVISING APCH CTL OF HIS INTENT TO CONDUCT A CAT III AUTOLAND APCH.

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.