Narrative:

After cleanup and during climb out (about 14000 ft) the aircraft yawed as though it were going through another aircraft's wake. Immediately the aircraft banked to the left and it required 3 1/2 units of right aileron to hold the aircraft level. There was no yawing tendency. I had the irc inspect the wings and see if he saw anything out of the ordinary. Reported back that both ailerons were dropping. I confirmed this with a visual inspection of the wing from the passenger cabin, returned to the cockpit and asked for a level off at 27000 ft. We contacted maintenance control through a phone patch and also dispatch (nrt) on VHF. We asked for a turn away from the airway and decided to return to nrt. We delayed dumping because nrt maintenance suggested that we put the flaps down and return them to see if we could correct the problem. We attempted flaps to 1 degree, but placing flaps down and retracting them did not alleviate the problem. We began fuel dumping and dumped down to 632000 pounds gross weight and made a normal approach and landing to narita. We were told that we were going to ship change immediately after the mechanics looked at the aircraft and we quickly collected our gear and transferred to another aircraft. Attached is the maintenance problem and solution: r-hand inboard aileron inoperative due to 1 out of 4 control cables, which constitute a loop cable, was cut broken between cca and package. Removed access panel and replaced the applicable cable assembly. Also, l-hand outboard aileron lockout actuator changed precautionally. Ship changed for continuation of nrt-jfk.

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Original NASA ASRS Text

Title: AILERON MALFUNCTION CAUSED FLC OF WDB ACR ACFT TO RETURN LAND.

Narrative: AFTER CLEANUP AND DURING CLBOUT (ABOUT 14000 FT) THE ACFT YAWED AS THOUGH IT WERE GOING THROUGH ANOTHER ACFT'S WAKE. IMMEDIATELY THE ACFT BANKED TO THE L AND IT REQUIRED 3 1/2 UNITS OF R AILERON TO HOLD THE ACFT LEVEL. THERE WAS NO YAWING TENDENCY. I HAD THE IRC INSPECT THE WINGS AND SEE IF HE SAW ANYTHING OUT OF THE ORDINARY. RPTED BACK THAT BOTH AILERONS WERE DROPPING. I CONFIRMED THIS WITH A VISUAL INSPECTION OF THE WING FROM THE PAX CABIN, RETURNED TO THE COCKPIT AND ASKED FOR A LEVEL OFF AT 27000 FT. WE CONTACTED MAINT CTL THROUGH A PHONE PATCH AND ALSO DISPATCH (NRT) ON VHF. WE ASKED FOR A TURN AWAY FROM THE AIRWAY AND DECIDED TO RETURN TO NRT. WE DELAYED DUMPING BECAUSE NRT MAINT SUGGESTED THAT WE PUT THE FLAPS DOWN AND RETURN THEM TO SEE IF WE COULD CORRECT THE PROB. WE ATTEMPTED FLAPS TO 1 DEG, BUT PLACING FLAPS DOWN AND RETRACTING THEM DID NOT ALLEVIATE THE PROB. WE BEGAN FUEL DUMPING AND DUMPED DOWN TO 632000 LBS GROSS WT AND MADE A NORMAL APCH AND LNDG TO NARITA. WE WERE TOLD THAT WE WERE GOING TO SHIP CHANGE IMMEDIATELY AFTER THE MECHS LOOKED AT THE ACFT AND WE QUICKLY COLLECTED OUR GEAR AND TRANSFERRED TO ANOTHER ACFT. ATTACHED IS THE MAINT PROB AND SOLUTION: R-HAND INBOARD AILERON INOP DUE TO 1 OUT OF 4 CTL CABLES, WHICH CONSTITUTE A LOOP CABLE, WAS CUT BROKEN BTWN CCA AND PACKAGE. REMOVED ACCESS PANEL AND REPLACED THE APPLICABLE CABLE ASSEMBLY. ALSO, L-HAND OUTBOARD AILERON LOCKOUT ACTUATOR CHANGED PRECAUTIONALLY. SHIP CHANGED FOR CONTINUATION OF NRT-JFK.

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.