Narrative:

We noticed on taxi out; rudder system #2 inoperative message. We stopped aircraft and problem solved with checklists during which time the message went out and stayed out. We waited about 10 mins and the message did not return. We then decided to take off and at about 4000 ft we observed both rudder system #1 and #2 inoperative. We then followed the checklist and declared an emergency with a precautionary return to the field. We landed the aircraft without incident and returned to the gate. Observed an apparent flight control malfunction dictating a precautionary return and declared emergency. Perhaps we should return to the gate at the first indication of a problem with any hydraulic system any time it occurs. Callback conversation with reporter acn #810242 revealed the following information: the aircraft type involved was an emb-145. The pilot flying found the rudder system to be operating normally during the return to land. Maintenance found a faulty sensor that was causing the erroneous fault warning.

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Original NASA ASRS Text

Title: EMB145 FLIGHT CREW RECEIVE EICAS MESSAGE RUDDER SYS 1 AND 2 INOP SHORTLY AFTER TAKE OFF. EMERGENCY IS DECLARED AND CREW RETURNS FOR UNEVENTFUL LANDING.

Narrative: WE NOTICED ON TAXI OUT; RUDDER SYS #2 INOP MESSAGE. WE STOPPED ACFT AND PROB SOLVED WITH CHKLISTS DURING WHICH TIME THE MESSAGE WENT OUT AND STAYED OUT. WE WAITED ABOUT 10 MINS AND THE MESSAGE DID NOT RETURN. WE THEN DECIDED TO TAKE OFF AND AT ABOUT 4000 FT WE OBSERVED BOTH RUDDER SYS #1 AND #2 INOP. WE THEN FOLLOWED THE CHKLIST AND DECLARED AN EMER WITH A PRECAUTIONARY RETURN TO THE FIELD. WE LANDED THE ACFT WITHOUT INCIDENT AND RETURNED TO THE GATE. OBSERVED AN APPARENT FLT CTL MALFUNCTION DICTATING A PRECAUTIONARY RETURN AND DECLARED EMER. PERHAPS WE SHOULD RETURN TO THE GATE AT THE FIRST INDICATION OF A PROB WITH ANY HYD SYS ANY TIME IT OCCURS. CALLBACK CONVERSATION WITH RPTR ACN #810242 REVEALED THE FOLLOWING INFO: THE AIRCRAFT TYPE INVOLVED WAS AN EMB-145. THE PILOT FLYING FOUND THE RUDDER SYSTEM TO BE OPERATING NORMALLY DURING THE RETURN TO LAND. MAINTENANCE FOUND A FAULTY SENSOR THAT WAS CAUSING THE ERRONEOUS FAULT WARNING.

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.