Narrative:

During takeoff roll at rotate speed, the flight control system rudder caution light illuminated, along with 'flight control' master caution light. The rudder light had previously been med'ed as intermittent. After takeoff the rudder light switch was selected off in order to extinguish the master caution light. Passing through FL215 the aircraft began to yaw quickly back and forth. The utility system rudder light rapidly illuminated and extinguished for a period of 2-3 seconds. The autoplt was immediately disconnected with no change. The aircraft returned to normal after 2-3 seconds of oscillation. I elected to return to pdx. En route back to pdx, the abnormal checklist for both rudder light on was accomplished. This rendered the aircraft in manual reversion. The landing was normal. Aircraft was delivered to maintenance for troubleshooting. Callback conversation with reporter revealed the following information: the reporter stated the aircraft was a fokker 28-4000 and departed with a deferred item on the rudder hydraulic power utility system light. The reporter said when maintenance worked the aircraft the corrective action was found to be the #2 system intermittent rudder power control shutoff valve which is normally de-energized open. The reporter stated the deferred item for the utility channel light system supplemental procedures were confusing at best and the combination of an intermittent shutoff valve in the #2 system caused the oscillation of the 2 rudder power unit shutoff valves. The reporter said the company has revised and amended the MEL supplemental procedures to preclude another incident. The NTSB has classified this as an incident.

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Original NASA ASRS Text

Title: A FOKKER 28-4000 IN CLB AT FL215 DECLARED AN EMER AND DIVERTED DUE TO UNCOMMANDED QUICK RUDDER YAW MOVEMENTS WITH #1 RUDDER UTILITY HYD LIGHT RAPIDLY ILLUMINATING CAUSED BY AN INTERMITTENT RUDDER PWR SHUTOFF VALVE AND AN IMPROPERLY DEFERRED RUDDER CHANNEL UTILITY LIGHT SYS.

Narrative: DURING TKOF ROLL AT ROTATE SPD, THE FLT CTL SYS RUDDER CAUTION LIGHT ILLUMINATED, ALONG WITH 'FLT CTL' MASTER CAUTION LIGHT. THE RUDDER LIGHT HAD PREVIOUSLY BEEN MED'ED AS INTERMITTENT. AFTER TKOF THE RUDDER LIGHT SWITCH WAS SELECTED OFF IN ORDER TO EXTINGUISH THE MASTER CAUTION LIGHT. PASSING THROUGH FL215 THE ACFT BEGAN TO YAW QUICKLY BACK AND FORTH. THE UTILITY SYS RUDDER LIGHT RAPIDLY ILLUMINATED AND EXTINGUISHED FOR A PERIOD OF 2-3 SECONDS. THE AUTOPLT WAS IMMEDIATELY DISCONNECTED WITH NO CHANGE. THE ACFT RETURNED TO NORMAL AFTER 2-3 SECONDS OF OSCILLATION. I ELECTED TO RETURN TO PDX. ENRTE BACK TO PDX, THE ABNORMAL CHKLIST FOR BOTH RUDDER LIGHT ON WAS ACCOMPLISHED. THIS RENDERED THE ACFT IN MANUAL REVERSION. THE LNDG WAS NORMAL. ACFT WAS DELIVERED TO MAINT FOR TROUBLESHOOTING. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS A FOKKER 28-4000 AND DEPARTED WITH A DEFERRED ITEM ON THE RUDDER HYD PWR UTILITY SYS LIGHT. THE RPTR SAID WHEN MAINT WORKED THE ACFT THE CORRECTIVE ACTION WAS FOUND TO BE THE #2 SYS INTERMITTENT RUDDER PWR CTL SHUTOFF VALVE WHICH IS NORMALLY DE-ENERGIZED OPEN. THE RPTR STATED THE DEFERRED ITEM FOR THE UTILITY CHANNEL LIGHT SYS SUPPLEMENTAL PROCS WERE CONFUSING AT BEST AND THE COMBINATION OF AN INTERMITTENT SHUTOFF VALVE IN THE #2 SYS CAUSED THE OSCILLATION OF THE 2 RUDDER PWR UNIT SHUTOFF VALVES. THE RPTR SAID THE COMPANY HAS REVISED AND AMENDED THE MEL SUPPLEMENTAL PROCS TO PRECLUDE ANOTHER INCIDENT. THE NTSB HAS CLASSIFIED THIS AS AN INCIDENT.

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.