Narrative:

To the best of my recollection this is what occurred. My first officer and myself picked up the aircraft in ZZZ. The aircraft had a logbook entry a few days prior regarding a rudder system inoperative message. The flight crew stated the message came on and off several times during the flight. The maintenance side state operations checks good no further action required. We thought it would be a good idea to keep this in mind just in case. We departed with 37 passengers and two alternates due to the poor weather at destination. The first officer was the pilot flying. Everything was standard until approximately 1500 ft at approximately 250 KTS the autopilot turned off and the autopilot yaw damp fail message briefly appeared and then the rudder system 1-2 inoperative message appeared and remained. The second the autopilot deactivated; the aircraft jerked to the left. We followed procedures in the aom. Once the second rudder system (per procedure) was turned off the aircraft made a hard jerk to the right. I told the first officer that we would transfer controls and asked him to reread the procedure to ensure it was accomplished correctly. We both agreed it would be wise to leave the system off. We notified ATC; declared an emergency; asked for crash and rescue; informed the flight attendant and made a PA to the passengers. At this point the aircraft was flying normally and we asked ATC if we could circle over ZZZ1 at 6000 ft in order to burn fuel to get below landing weight. Being right over ZZZ1 gave us the option for an immediate landing in case the aircraft did not fly correctly. During our circling to burn fuel; we sent an ACARS message to maintenance asking if they had any idea how the aircraft might handle fully configured and at a slow speed for approach. They said they were unsure. We finally made a normal landing at ZZZ1 and taxied to the gate under our own power.callback conversation with reporter revealed the following information: the captain reported that the rudder does; in fact; revert to manual operation in the event of rudder 'boost' system failures. Thus; yaw control is not lost but control inputs require more effort to obtain the desired rudder deflection. He stated the earlier write up referred only to intermittent flickers of the rudder system inoperative message; and that maintenance was unable to duplicate that anomaly.

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Original NASA ASRS Text

Title: E135 FLT CREW EXPERIENCES LOSS OF RUDDER SYSTEMS ONE AND TWO.

Narrative: TO THE BEST OF MY RECOLLECTION THIS IS WHAT OCCURRED. MY FO AND MYSELF PICKED UP THE AIRCRAFT IN ZZZ. THE AIRCRAFT HAD A LOGBOOK ENTRY A FEW DAYS PRIOR REGARDING A RUDDER SYSTEM INOPERATIVE MESSAGE. THE FLIGHT CREW STATED THE MESSAGE CAME ON AND OFF SEVERAL TIMES DURING THE FLIGHT. THE MAINTENANCE SIDE STATE OPS CHECKS GOOD NO FURTHER ACTION REQUIRED. WE THOUGHT IT WOULD BE A GOOD IDEA TO KEEP THIS IN MIND JUST IN CASE. WE DEPARTED WITH 37 PASSENGERS AND TWO ALTERNATES DUE TO THE POOR WEATHER AT DEST. THE FO WAS THE PILOT FLYING. EVERYTHING WAS STANDARD UNTIL APPROXIMATELY 1500 FT AT APPROXIMATELY 250 KTS THE AUTOPILOT TURNED OFF AND THE AUTOPILOT YAW DAMP FAIL MESSAGE BRIEFLY APPEARED AND THEN THE RUDDER SYS 1-2 INOP MESSAGE APPEARED AND REMAINED. THE SECOND THE AUTOPILOT DEACTIVATED; THE AIRCRAFT JERKED TO THE LEFT. WE FOLLOWED PROCEDURES IN THE AOM. ONCE THE SECOND RUDDER SYSTEM (PER PROCEDURE) WAS TURNED OFF THE AIRCRAFT MADE A HARD JERK TO THE RIGHT. I TOLD THE FO THAT WE WOULD TRANSFER CONTROLS AND ASKED HIM TO REREAD THE PROCEDURE TO ENSURE IT WAS ACCOMPLISHED CORRECTLY. WE BOTH AGREED IT WOULD BE WISE TO LEAVE THE SYSTEM OFF. WE NOTIFIED ATC; DECLARED AN EMERGENCY; ASKED FOR CRASH AND RESCUE; INFORMED THE FLIGHT ATTENDANT AND MADE A PA TO THE PASSENGERS. AT THIS POINT THE AIRCRAFT WAS FLYING NORMALLY AND WE ASKED ATC IF WE COULD CIRCLE OVER ZZZ1 AT 6000 FT IN ORDER TO BURN FUEL TO GET BELOW LANDING WEIGHT. BEING RIGHT OVER ZZZ1 GAVE US THE OPTION FOR AN IMMEDIATE LANDING IN CASE THE AIRCRAFT DID NOT FLY CORRECTLY. DURING OUR CIRCLING TO BURN FUEL; WE SENT AN ACARS MESSAGE TO MAINT ASKING IF THEY HAD ANY IDEA HOW THE AIRCRAFT MIGHT HANDLE FULLY CONFIGURED AND AT A SLOW SPEED FOR APPROACH. THEY SAID THEY WERE UNSURE. WE FINALLY MADE A NORMAL LANDING AT ZZZ1 AND TAXIED TO THE GATE UNDER OUR OWN POWER.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE CAPTAIN REPORTED THAT THE RUDDER DOES; IN FACT; REVERT TO MANUAL OPERATION IN THE EVENT OF RUDDER 'BOOST' SYSTEM FAILURES. THUS; YAW CONTROL IS NOT LOST BUT CONTROL INPUTS REQUIRE MORE EFFORT TO OBTAIN THE DESIRED RUDDER DEFLECTION. HE STATED THE EARLIER WRITE UP REFERRED ONLY TO INTERMITTENT FLICKERS OF THE RUDDER SYSTEM INOP MSG; AND THAT MAINT WAS UNABLE TO DUPLICATE THAT ANOMALY.

Data retrieved from NASA's ASRS site as of May 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.