Narrative:

During the taxi checklist/flight control check, we noticed that when the captain applied right rudder, the rudder travel unrestr annunciator light went out as right rudder was applied and would reilluminate as left rudder was applied and the right rudder approached the neutral position. Neither of us had ever seen this before so we stopped, checked the abnormal checklists in the operations manual part 1. There is no mention of this condition in the manual, so we arranged a phone patch to tulsa technician and discussed the problem with the duty engineer. We all agreed that there was a problem and we taxied back to the gate and called a mechanic. The mechanic arrived and via cell phone to tulsa we discovered a portion of the rudder system was out of adjustment. The mechanic was able to adjust the equipment and we finished the log and departed. After returning to dfw, I called the DC9 fleet supervisor/captain to discuss the occurrence. He had never heard of this happening either and promised to follow up. Supervisor/captain conferred with person at maintenance and they informed me that the problem as encountered by us could be a serious situation should the rudder be restr and we experience an engine failure requiring use of full rudder travel. I feel a change to the taxi checklist is needed in the form of a note to ensure that the rudder travel unrestr light stays illuminated while completing the rudder control check. I realize that in the interest of brevity and timeliness, I have left out details of this occurrence. I will be available to debrief concerned individuals as needed. Callback conversation with reporter revealed the following information: the reporter stated the rudder unrestr light should always be on with no input from the airspeed bellows. The reporter stated on the ground during taxi out the light went out indicating the rudder had a restr with right rudder input. The reporter said neither the captain nor the reporter had ever experienced this type of failure. The reporter said maintenance found the rudder travel unrestr switch mounting plate on the rudder hydraulic power package out of adjustment. The reporter stated the major concern was the rudder restr during takeoff in an engine out situation when a lot of rudder is required. The reporter said he was unaware if the aircraft had any previous history on rudder indication problems.

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Original NASA ASRS Text

Title: AN MD SUPER 80 ON TAXI OUT RETURNED TO THE GATE DUE TO THE RUDDER CTL FAILURE DISCOVERED DURING THE RUDDER CTL CHKLIST PROC.

Narrative: DURING THE TAXI CHKLIST/FLT CTL CHK, WE NOTICED THAT WHEN THE CAPT APPLIED R RUDDER, THE RUDDER TRAVEL UNRESTR ANNUNCIATOR LIGHT WENT OUT AS R RUDDER WAS APPLIED AND WOULD REILLUMINATE AS L RUDDER WAS APPLIED AND THE R RUDDER APCHED THE NEUTRAL POS. NEITHER OF US HAD EVER SEEN THIS BEFORE SO WE STOPPED, CHKED THE ABNORMAL CHKLISTS IN THE OPS MANUAL PART 1. THERE IS NO MENTION OF THIS CONDITION IN THE MANUAL, SO WE ARRANGED A PHONE PATCH TO TULSA TECHNICIAN AND DISCUSSED THE PROB WITH THE DUTY ENGINEER. WE ALL AGREED THAT THERE WAS A PROB AND WE TAXIED BACK TO THE GATE AND CALLED A MECH. THE MECH ARRIVED AND VIA CELL PHONE TO TULSA WE DISCOVERED A PORTION OF THE RUDDER SYS WAS OUT OF ADJUSTMENT. THE MECH WAS ABLE TO ADJUST THE EQUIP AND WE FINISHED THE LOG AND DEPARTED. AFTER RETURNING TO DFW, I CALLED THE DC9 FLEET SUPVR/CAPT TO DISCUSS THE OCCURRENCE. HE HAD NEVER HEARD OF THIS HAPPENING EITHER AND PROMISED TO FOLLOW UP. SUPVR/CAPT CONFERRED WITH PERSON AT MAINT AND THEY INFORMED ME THAT THE PROB AS ENCOUNTERED BY US COULD BE A SERIOUS SIT SHOULD THE RUDDER BE RESTR AND WE EXPERIENCE AN ENG FAILURE REQUIRING USE OF FULL RUDDER TRAVEL. I FEEL A CHANGE TO THE TAXI CHKLIST IS NEEDED IN THE FORM OF A NOTE TO ENSURE THAT THE RUDDER TRAVEL UNRESTR LIGHT STAYS ILLUMINATED WHILE COMPLETING THE RUDDER CTL CHK. I REALIZE THAT IN THE INTEREST OF BREVITY AND TIMELINESS, I HAVE LEFT OUT DETAILS OF THIS OCCURRENCE. I WILL BE AVAILABLE TO DEBRIEF CONCERNED INDIVIDUALS AS NEEDED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE RUDDER UNRESTR LIGHT SHOULD ALWAYS BE ON WITH NO INPUT FROM THE AIRSPD BELLOWS. THE RPTR STATED ON THE GND DURING TAXI OUT THE LIGHT WENT OUT INDICATING THE RUDDER HAD A RESTR WITH R RUDDER INPUT. THE RPTR SAID NEITHER THE CAPT NOR THE RPTR HAD EVER EXPERIENCED THIS TYPE OF FAILURE. THE RPTR SAID MAINT FOUND THE RUDDER TRAVEL UNRESTR SWITCH MOUNTING PLATE ON THE RUDDER HYD PWR PACKAGE OUT OF ADJUSTMENT. THE RPTR STATED THE MAJOR CONCERN WAS THE RUDDER RESTR DURING TKOF IN AN ENG OUT SIT WHEN A LOT OF RUDDER IS REQUIRED. THE RPTR SAID HE WAS UNAWARE IF THE ACFT HAD ANY PREVIOUS HISTORY ON RUDDER INDICATION PROBS.

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.