Narrative:

While climbing out of portland, the captain was still hand-flying the aircraft when he noted a 'T' fault light on the autoplt control panel. He tried disengaging the yaw dampener, and switched the autoplt xfer switch over to the first officer side, then back to his to clear it up. The 'T' remained on. Upon re-engaging the yaw dampener, an 'east' fault light came on the same panel. The captain had me consult the QRH for the autoplt problems, but the problems we were encountering did not match any listed in the book (ie no red lights on the map). Then the captain noted his flight director command bars were acting funny. I looked over at his flight director and saw his command bars pitched up about 15 degrees. When he reset them, they returned to our actual pitch, then slowly rose, uncommanded, back to 15 degrees or so up. I glanced at mine, and noticed they appeared to be doing the same. I reset my command bars to our current pitch, then they immediately rose back up to 15 degrees or so climb. I reset them several times, and each time the command bars would rise uncommanded again. I concurred with the captain that the flight director was having problems, and I turned my side off. While we continued to climb, the captain xferred the flight controls to the first officer so he could confer with maintenance about the problem. After the captain said he was back, the aircraft began to pitch up, as if though the autoplt was trying to control the climb. I asked the captain if he had engaged the autoplt. He said no, but I could feel the aircraft trying to pitch up, with increasing back pressure on the yoke. I hit the autoplt disconnect switch, which abruptly relieved the pitch-up. The captain then said he had the flight controls, and we xferred the controls back to him. The captain then said to declare an emergency, but before I could call ZSE, the captain began fighting the controls as the nose pitched up, and he indicated he needed assistance pushing forward on the yoke. I began pushing the yoke forward with my right hand, simultaneously thumbing the autoplt disconnect switch with my right thumb, and tried running the elevator trim wheel forward with my left, but it didn't seem to have any effect. (Note: I kept my hand on the elevator trim wheel to feel for movement as well as trimming nose down pitch, but did not feel it moving as it would if the autoplt were adjusting it.) things were happening very quickly at this point. I saw the captain was straining to push forward on the yoke with both hands, while I pushed with mine. I began to go through the run-away-trim checklist and had got past the autoplt disconnect switch, and holding the trim wheel (which had still not moved, that I could tell, as a trim run away would). I noticed the airspeed was down to 150 KTS and the pitch was around 15-17 degrees. The captain said to pull the elevator disconnect. I was still mindset on the autoplt disconnect, and hit that a couple more times with no effect, then the captain got it across what he wanted. I asked if he were sure, and he quickly replied yes. I pulled the elevator disconnect handle which immediately returned control of the aircraft to us. The captain asked if I had elevator control -- I affirmed yes, that I had elevator control on my side. Then he said, 'you have the flight controls,' I affirmed that I had the flight controls. He then said to declare an emergency and tell ATC we were returning to pdx. I did so while the captain coordinated with our flight attendant. The captain came back as ATC was asking me for the nature of the emergency, and he beat me to the transmit switch to tell them to standby. We ran a descent check, and ran the QRH elevator disconnect checklist. While we had altitude, the captain had us slow down to see what the confign changes of gear and flaps would do, then we landed on runway 28L at portland. Postscript: while running the originating checklist, I noticed the stall warning test buttons were sticky, as though someone had spilled a soda on them. I noted this to the captain. During each of the pitch ups, while I was flying and after the captain asked me for assistance on the yoke, I ran the elevator trim wheel forward with my left hand. When not trying to run itforward, I kept my hand lightly on the wheel to see if it were moving. Though I had to remove my hand a number of times, I did not notice the wheel moving on its own. By the time that this report was written, the word was maintenance had determined that a soda had previously spilled on the console, which got into the wiring of the autoplt system, causing our problems. Supplemental information from acn 476716: we configured the aircraft for landing a little earlier than normal just in case we had adverse affects with the flaps. We briefed the normal descent and before landing checks. The QRH called for a flaps 25 degree landing. After we shut down the aircraft I went back into the cabin to talk to the passenger.

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Original NASA ASRS Text

Title: A CLBING E120 ACFT HAS AN UNCOMMANDED PITCH UP, REQUIRING THE FORCE OF BOTH PLT'S INPUTS ON THE YOKE PRIOR TO PULLING THE ELEVATOR DISCONNECT.

Narrative: WHILE CLBING OUT OF PORTLAND, THE CAPT WAS STILL HAND-FLYING THE ACFT WHEN HE NOTED A 'T' FAULT LIGHT ON THE AUTOPLT CTL PANEL. HE TRIED DISENGAGING THE YAW DAMPENER, AND SWITCHED THE AUTOPLT XFER SWITCH OVER TO THE FO SIDE, THEN BACK TO HIS TO CLR IT UP. THE 'T' REMAINED ON. UPON RE-ENGAGING THE YAW DAMPENER, AN 'E' FAULT LIGHT CAME ON THE SAME PANEL. THE CAPT HAD ME CONSULT THE QRH FOR THE AUTOPLT PROBS, BUT THE PROBS WE WERE ENCOUNTERING DID NOT MATCH ANY LISTED IN THE BOOK (IE NO RED LIGHTS ON THE MAP). THEN THE CAPT NOTED HIS FLT DIRECTOR COMMAND BARS WERE ACTING FUNNY. I LOOKED OVER AT HIS FLT DIRECTOR AND SAW HIS COMMAND BARS PITCHED UP ABOUT 15 DEGS. WHEN HE RESET THEM, THEY RETURNED TO OUR ACTUAL PITCH, THEN SLOWLY ROSE, UNCOMMANDED, BACK TO 15 DEGS OR SO UP. I GLANCED AT MINE, AND NOTICED THEY APPEARED TO BE DOING THE SAME. I RESET MY COMMAND BARS TO OUR CURRENT PITCH, THEN THEY IMMEDIATELY ROSE BACK UP TO 15 DEGS OR SO CLB. I RESET THEM SEVERAL TIMES, AND EACH TIME THE COMMAND BARS WOULD RISE UNCOMMANDED AGAIN. I CONCURRED WITH THE CAPT THAT THE FLT DIRECTOR WAS HAVING PROBS, AND I TURNED MY SIDE OFF. WHILE WE CONTINUED TO CLB, THE CAPT XFERRED THE FLT CTLS TO THE FO SO HE COULD CONFER WITH MAINT ABOUT THE PROB. AFTER THE CAPT SAID HE WAS BACK, THE ACFT BEGAN TO PITCH UP, AS IF THOUGH THE AUTOPLT WAS TRYING TO CTL THE CLB. I ASKED THE CAPT IF HE HAD ENGAGED THE AUTOPLT. HE SAID NO, BUT I COULD FEEL THE ACFT TRYING TO PITCH UP, WITH INCREASING BACK PRESSURE ON THE YOKE. I HIT THE AUTOPLT DISCONNECT SWITCH, WHICH ABRUPTLY RELIEVED THE PITCH-UP. THE CAPT THEN SAID HE HAD THE FLT CTLS, AND WE XFERRED THE CTLS BACK TO HIM. THE CAPT THEN SAID TO DECLARE AN EMER, BUT BEFORE I COULD CALL ZSE, THE CAPT BEGAN FIGHTING THE CTLS AS THE NOSE PITCHED UP, AND HE INDICATED HE NEEDED ASSISTANCE PUSHING FORWARD ON THE YOKE. I BEGAN PUSHING THE YOKE FORWARD WITH MY R HAND, SIMULTANEOUSLY THUMBING THE AUTOPLT DISCONNECT SWITCH WITH MY R THUMB, AND TRIED RUNNING THE ELEVATOR TRIM WHEEL FORWARD WITH MY L, BUT IT DIDN'T SEEM TO HAVE ANY EFFECT. (NOTE: I KEPT MY HAND ON THE ELEVATOR TRIM WHEEL TO FEEL FOR MOVEMENT AS WELL AS TRIMMING NOSE DOWN PITCH, BUT DID NOT FEEL IT MOVING AS IT WOULD IF THE AUTOPLT WERE ADJUSTING IT.) THINGS WERE HAPPENING VERY QUICKLY AT THIS POINT. I SAW THE CAPT WAS STRAINING TO PUSH FORWARD ON THE YOKE WITH BOTH HANDS, WHILE I PUSHED WITH MINE. I BEGAN TO GO THROUGH THE RUN-AWAY-TRIM CHKLIST AND HAD GOT PAST THE AUTOPLT DISCONNECT SWITCH, AND HOLDING THE TRIM WHEEL (WHICH HAD STILL NOT MOVED, THAT I COULD TELL, AS A TRIM RUN AWAY WOULD). I NOTICED THE AIRSPD WAS DOWN TO 150 KTS AND THE PITCH WAS AROUND 15-17 DEGS. THE CAPT SAID TO PULL THE ELEVATOR DISCONNECT. I WAS STILL MINDSET ON THE AUTOPLT DISCONNECT, AND HIT THAT A COUPLE MORE TIMES WITH NO EFFECT, THEN THE CAPT GOT IT ACROSS WHAT HE WANTED. I ASKED IF HE WERE SURE, AND HE QUICKLY REPLIED YES. I PULLED THE ELEVATOR DISCONNECT HANDLE WHICH IMMEDIATELY RETURNED CTL OF THE ACFT TO US. THE CAPT ASKED IF I HAD ELEVATOR CTL -- I AFFIRMED YES, THAT I HAD ELEVATOR CTL ON MY SIDE. THEN HE SAID, 'YOU HAVE THE FLT CTLS,' I AFFIRMED THAT I HAD THE FLT CTLS. HE THEN SAID TO DECLARE AN EMER AND TELL ATC WE WERE RETURNING TO PDX. I DID SO WHILE THE CAPT COORDINATED WITH OUR FLT ATTENDANT. THE CAPT CAME BACK AS ATC WAS ASKING ME FOR THE NATURE OF THE EMER, AND HE BEAT ME TO THE XMIT SWITCH TO TELL THEM TO STANDBY. WE RAN A DSCNT CHK, AND RAN THE QRH ELEVATOR DISCONNECT CHKLIST. WHILE WE HAD ALT, THE CAPT HAD US SLOW DOWN TO SEE WHAT THE CONFIGN CHANGES OF GEAR AND FLAPS WOULD DO, THEN WE LANDED ON RWY 28L AT PORTLAND. POSTSCRIPT: WHILE RUNNING THE ORIGINATING CHKLIST, I NOTICED THE STALL WARNING TEST BUTTONS WERE STICKY, AS THOUGH SOMEONE HAD SPILLED A SODA ON THEM. I NOTED THIS TO THE CAPT. DURING EACH OF THE PITCH UPS, WHILE I WAS FLYING AND AFTER THE CAPT ASKED ME FOR ASSISTANCE ON THE YOKE, I RAN THE ELEVATOR TRIM WHEEL FORWARD WITH MY L HAND. WHEN NOT TRYING TO RUN ITFORWARD, I KEPT MY HAND LIGHTLY ON THE WHEEL TO SEE IF IT WERE MOVING. THOUGH I HAD TO REMOVE MY HAND A NUMBER OF TIMES, I DID NOT NOTICE THE WHEEL MOVING ON ITS OWN. BY THE TIME THAT THIS RPT WAS WRITTEN, THE WORD WAS MAINT HAD DETERMINED THAT A SODA HAD PREVIOUSLY SPILLED ON THE CONSOLE, WHICH GOT INTO THE WIRING OF THE AUTOPLT SYS, CAUSING OUR PROBS. SUPPLEMENTAL INFO FROM ACN 476716: WE CONFIGURED THE ACFT FOR LNDG A LITTLE EARLIER THAN NORMAL JUST IN CASE WE HAD ADVERSE AFFECTS WITH THE FLAPS. WE BRIEFED THE NORMAL DSCNT AND BEFORE LNDG CHKS. THE QRH CALLED FOR A FLAPS 25 DEG LNDG. AFTER WE SHUT DOWN THE ACFT I WENT BACK INTO THE CABIN TO TALK TO THE PAX.

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.