Narrative:

My understanding of the airbus rudder system is this: the rudder system is the only system in our completely 'fly-by-wire' flight controls that has a manual cable backup. When properly rigged (as most of our airbus aircraft are) when you reach full travel on the rudder pedal; you hit a mechanical stop which coincides with both the electrical and cable system maximum rudder deflection to that side. On the incident aircraft; while doing the flight control check; the right pedal went to the stop; and the left pedal stopped significantly short of the mechanical stop. It was very noticeable to me. The first officer responded with 'check' after the test; meaning all is well; but since we were sitting waiting for a maintenance document (unrelated fuel display issue) I re-did the rudder check and watched the display myself. The rudder swung to the right well past the maximum deflection box on the flight control display. To the left; the rudder stopped well short of the full deflection box. The neutral point was perfectly centered. Other than the neutral point being exactly centered; the rudder acted like it was rigged too far right; getting more than the maximum allowable deflection on the right side; and less than maximum deflection left. The 'stop' at the bottom of the left pedal throw was what I call a 'cable stop.' it wasn't the hard; mechanical stop like we had on the right; it was a firm; yet spongy stop like when you hit the end of cable movement. I could push harder and get the pedal to move a tiny bit more; but the rudder display didn't change at all; and I couldn't push hard enough to reach the mechanical stop. The first officer confirmed the display discrepancy and I had him try his side also. Exactly the same results and feel. I contacted maintenance and we did some tests before returning to the gate. Contract maintenance came and did many; many things; including checking for FOD under the pedals; trying different computers; different hydraulic systems; etc; and the results were always the same. The aircraft is still down as far as I know. So here's the hard questions/lessons: how in the world has this jet been flying around this way and nobody but me noticed? Well; part of that answer is something I observed as a critical problem with airbus training. My first officer missed the display discrepancy the first time I did the flight control check. He had always looked for swing in the right direction and not where the rudder stopped. Why? That's because (and as a commuter who usually is forced to ride the jumpseat; I can 100 percent back this up) at least half the captain's do the flight control check like they're in a cessna 152. They hit the stops with the stick and pedals and then immediately back to neutral. The flight controls only have time to start to move in the right direction before they are moving back to neutral or in the opposite direction. How long was this jet flying around out of rig? I don't have an answer to that one. Why didn't any other captain who flew this catch this (and this one was hugely noticeable to me)? My guess is that they have no idea what they are checking when they do the flight control check. This is serious. What would have happened if a pilot were to land in a maximum crosswind with less than maximum rudder available? What if we dropped the right engine at V1 with a strong crosswind from the right? What if a pilot used full right rudder and the vertical stabilizer departed the aircraft due to overloading from moving too far? In my opinion; this is an issue that must be addressed today; immediately. I won't tell anyone how to do their job; but this would seem to warrant a pilot notice to all airbus pilots explaining the requirements of the flight control check; why we do it this way; what the first officer's are to look for; and that the capts should feel the mechanical stop at the bottom of both rudder pedal throws. If there is any way for me to be informed of any progress on this aircraft and/or this issue; please do so. Again; I think this is very important.callback conversation with reporter revealed the following information: the reporter revealed maintenance found the rudder to be out of rig. Reportedly the flight control computer will hold a normal center position so the out of rig condition was not obvious to the flight crews; but potentially could have presented a directional control challenge had full left rudder been required.

Google
 

Original NASA ASRS Text

Title: AN A320 PLT RPTS A PRE-TKOF FLT CTLR CHECK REVEALING A FULL R RUDDER PEDAL DEFLECTION WHILE L RUDDER BLOCKED SHORT OF THE MECHANICAL STOP.

Narrative: MY UNDERSTANDING OF THE AIRBUS RUDDER SYSTEM IS THIS: THE RUDDER SYSTEM IS THE ONLY SYSTEM IN OUR COMPLETELY 'FLY-BY-WIRE' FLT CONTROLS THAT HAS A MANUAL CABLE BACKUP. WHEN PROPERLY RIGGED (AS MOST OF OUR AIRBUS ACFT ARE) WHEN YOU REACH FULL TRAVEL ON THE RUDDER PEDAL; YOU HIT A MECHANICAL STOP WHICH COINCIDES WITH BOTH THE ELECTRICAL AND CABLE SYSTEM MAXIMUM RUDDER DEFLECTION TO THAT SIDE. ON THE INCIDENT ACFT; WHILE DOING THE FLT CONTROL CHECK; THE RIGHT PEDAL WENT TO THE STOP; AND THE LEFT PEDAL STOPPED SIGNIFICANTLY SHORT OF THE MECHANICAL STOP. IT WAS VERY NOTICEABLE TO ME. THE FO RESPONDED WITH 'CHECK' AFTER THE TEST; MEANING ALL IS WELL; BUT SINCE WE WERE SITTING WAITING FOR A MAINT DOCUMENT (UNRELATED FUEL DISPLAY ISSUE) I RE-DID THE RUDDER CHECK AND WATCHED THE DISPLAY MYSELF. THE RUDDER SWUNG TO THE RIGHT WELL PAST THE MAXIMUM DEFLECTION BOX ON THE FLT CONTROL DISPLAY. TO THE LEFT; THE RUDDER STOPPED WELL SHORT OF THE FULL DEFLECTION BOX. THE NEUTRAL POINT WAS PERFECTLY CENTERED. OTHER THAN THE NEUTRAL POINT BEING EXACTLY CENTERED; THE RUDDER ACTED LIKE IT WAS RIGGED TOO FAR RIGHT; GETTING MORE THAN THE MAX ALLOWABLE DEFLECTION ON THE RIGHT SIDE; AND LESS THAN MAXIMUM DEFLECTION LEFT. THE 'STOP' AT THE BOTTOM OF THE LEFT PEDAL THROW WAS WHAT I CALL A 'CABLE STOP.' IT WASN'T THE HARD; MECHANICAL STOP LIKE WE HAD ON THE RIGHT; IT WAS A FIRM; YET SPONGY STOP LIKE WHEN YOU HIT THE END OF CABLE MOVEMENT. I COULD PUSH HARDER AND GET THE PEDAL TO MOVE A TINY BIT MORE; BUT THE RUDDER DISPLAY DIDN'T CHANGE AT ALL; AND I COULDN'T PUSH HARD ENOUGH TO REACH THE MECHANICAL STOP. THE FO CONFIRMED THE DISPLAY DISCREPANCY AND I HAD HIM TRY HIS SIDE ALSO. EXACTLY THE SAME RESULTS AND FEEL. I CONTACTED MAINT AND WE DID SOME TESTS BEFORE RETURNING TO THE GATE. CONTRACT MAINT CAME AND DID MANY; MANY THINGS; INCLUDING CHECKING FOR FOD UNDER THE PEDALS; TRYING DIFFERENT COMPUTERS; DIFFERENT HYDRAULIC SYSTEMS; ETC; AND THE RESULTS WERE ALWAYS THE SAME. THE ACFT IS STILL DOWN AS FAR AS I KNOW. SO HERE'S THE HARD QUESTIONS/LESSONS: HOW IN THE WORLD HAS THIS JET BEEN FLYING AROUND THIS WAY AND NOBODY BUT ME NOTICED? WELL; PART OF THAT ANSWER IS SOMETHING I OBSERVED AS A CRITICAL PROBLEM WITH AIRBUS TRAINING. MY FO MISSED THE DISPLAY DISCREPANCY THE FIRST TIME I DID THE FLT CONTROL CHECK. HE HAD ALWAYS LOOKED FOR SWING IN THE RIGHT DIRECTION AND NOT WHERE THE RUDDER STOPPED. WHY? THAT'S BECAUSE (AND AS A COMMUTER WHO USUALLY IS FORCED TO RIDE THE JUMPSEAT; I CAN 100 PERCENT BACK THIS UP) AT LEAST HALF THE CAPT'S DO THE FLT CONTROL CHECK LIKE THEY'RE IN A CESSNA 152. THEY HIT THE STOPS WITH THE STICK AND PEDALS AND THEN IMMEDIATELY BACK TO NEUTRAL. THE FLT CONTROLS ONLY HAVE TIME TO START TO MOVE IN THE RIGHT DIRECTION BEFORE THEY ARE MOVING BACK TO NEUTRAL OR IN THE OPPOSITE DIRECTION. HOW LONG WAS THIS JET FLYING AROUND OUT OF RIG? I DON'T HAVE AN ANSWER TO THAT ONE. WHY DIDN'T ANY OTHER CAPT WHO FLEW THIS CATCH THIS (AND THIS ONE WAS HUGELY NOTICEABLE TO ME)? MY GUESS IS THAT THEY HAVE NO IDEA WHAT THEY ARE CHECKING WHEN THEY DO THE FLT CONTROL CHECK. THIS IS SERIOUS. WHAT WOULD HAVE HAPPENED IF A PLT WERE TO LAND IN A MAXIMUM CROSSWIND WITH LESS THAN MAXIMUM RUDDER AVAILABLE? WHAT IF WE DROPPED THE RIGHT ENGINE AT V1 WITH A STRONG CROSSWIND FROM THE RIGHT? WHAT IF A PLT USED FULL RIGHT RUDDER AND THE VERTICAL STABILIZER DEPARTED THE ACFT DUE TO OVERLOADING FROM MOVING TOO FAR? IN MY OPINION; THIS IS AN ISSUE THAT MUST BE ADDRESSED TODAY; IMMEDIATELY. I WON'T TELL ANYONE HOW TO DO THEIR JOB; BUT THIS WOULD SEEM TO WARRANT A PLT NOTICE TO ALL AIRBUS PLTS EXPLAINING THE REQUIREMENTS OF THE FLT CONTROL CHECK; WHY WE DO IT THIS WAY; WHAT THE FO'S ARE TO LOOK FOR; AND THAT THE CAPTS SHOULD FEEL THE MECHANICAL STOP AT THE BOTTOM OF BOTH RUDDER PEDAL THROWS. IF THERE IS ANY WAY FOR ME TO BE INFORMED OF ANY PROGRESS ON THIS ACFT AND/OR THIS ISSUE; PLEASE DO SO. AGAIN; I THINK THIS IS VERY IMPORTANT.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE REPORTER REVEALED MAINTENANCE FOUND THE RUDDER TO BE OUT OF RIG. REPORTEDLY THE FLIGHT CONTROL COMPUTER WILL HOLD A NORMAL CENTER POSITION SO THE OUT OF RIG CONDITION WAS NOT OBVIOUS TO THE FLIGHT CREWS; BUT POTENTIALLY COULD HAVE PRESENTED A DIRECTIONAL CONTROL CHALLENGE HAD FULL LEFT RUDDER BEEN REQUIRED.

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.