Narrative:

After departure from koa, between 800-1000 ft in climb and 30 degree bank turn, felt aircraft yaw. Engine check was good and cockpit scan did not reveal any problems. Continued climb. While passing FL190, experienced yaw -- left to right -- with roll and bank angles 15-20 degrees. Disengaged autoplt and started to level off. Notified by ZHN that we were off course and heading and not climbing to FL230. Captain informed ZHN that we were experiencing flight control problems while I started to turn left back on course, oscillations (roll) recurred. Asked captain to disconnect yaw damper and aircraft oscillated several cycles and settled down. Captain declared an emergency and requested descent from FL190 with heading and vectors to hnl runway 8R and uneventful landing. Callback conversation with reporter revealed the following information: this was a yaw damper problem. Coffee had spilled and drained into the electronics compartment and was dripping on the yaw damper coupler. Repairs were made and aircraft was returned to service. Another incident of a similar nature occurred approximately 1 week alter.

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Original NASA ASRS Text

Title: B737-200 EXPERIENCES YAW AFTER TKOF AND AGAIN AT FL190. POSITIVE CTL WAS REGAINED WITH YAW DAMPER OFF. EMER DECLARED AND DIVERTED TO HNL, HI.

Narrative: AFTER DEP FROM KOA, BTWN 800-1000 FT IN CLB AND 30 DEG BANK TURN, FELT ACFT YAW. ENG CHK WAS GOOD AND COCKPIT SCAN DID NOT REVEAL ANY PROBS. CONTINUED CLB. WHILE PASSING FL190, EXPERIENCED YAW -- L TO R -- WITH ROLL AND BANK ANGLES 15-20 DEGS. DISENGAGED AUTOPLT AND STARTED TO LEVEL OFF. NOTIFIED BY ZHN THAT WE WERE OFF COURSE AND HDG AND NOT CLBING TO FL230. CAPT INFORMED ZHN THAT WE WERE EXPERIENCING FLT CTL PROBS WHILE I STARTED TO TURN L BACK ON COURSE, OSCILLATIONS (ROLL) RECURRED. ASKED CAPT TO DISCONNECT YAW DAMPER AND ACFT OSCILLATED SEVERAL CYCLES AND SETTLED DOWN. CAPT DECLARED AN EMER AND REQUESTED DSCNT FROM FL190 WITH HDG AND VECTORS TO HNL RWY 8R AND UNEVENTFUL LNDG. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THIS WAS A YAW DAMPER PROB. COFFEE HAD SPILLED AND DRAINED INTO THE ELECTRONICS COMPARTMENT AND WAS DRIPPING ON THE YAW DAMPER COUPLER. REPAIRS WERE MADE AND ACFT WAS RETURNED TO SVC. ANOTHER INCIDENT OF A SIMILAR NATURE OCCURRED APPROX 1 WK ALTER.

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.