ACR MDT ACFT ABNORMAL ELEVATOR CTL.

Narrative

THIS FLT ORIGINATED IN MINNEAPOLIS AND WAS ENRTE TO ATY (WATERTOWN; SD). PRIOR TO THE FLT; THE CAPT; MYSELF (FO) AND AN FAA AVIONICS INSPECTOR WHO WAS A JUMPSEAT RIDER PREFLTED OUR MDT ACFT. WE NOTICED NO ABNORMALITIES DURING OUR PREFLT OR OUR RWY ITEMS FLT CTL CHK AND PROCEEDED WITH A NORMAL DEP. APPROX 70 MI E OF FSD; AT CRUISE SPD AND AT 10000 FT MSL; I BEGAN A CLB TO 12000 FT MSL DUE TO A CLOUD LAYER AND THE POSSIBILITY OF TURB. AS THE ACFT PASSED THROUGH 11000 FT MSL; I FELT THE ELEVATOR AND ELEVATOR TRIM STICK. WHILE ATTEMPTING TO LEVEL THE ACFT; BY APPLYING FORWARD PRESSURE; I FELT THE ELEVATOR POP FREE ALMOST TAKING THE CTLS OUT OF MY HANDS. THIS HAPPENED 3 OR 4 TIMES OVER A SHORT PERIOD OF TIME; MAYBE 15 TO 20 SECONDS. I IMMEDIATELY NOTIFIED THE CAPT; WHO HAD ALREADY NOTICED WE HAD A PROBLEM; AND ASKED HIM TO FEEL THE CTLS WHICH HE DID. THE CAPT IMMEDIATELY FELT THE ABNORMALITY AND FLEW THE ACFT FOR MOST ALL THE REMAINDER OF THE FLT. WE DECIDED TO DIVERT TO FSD (SIOUX FALLS; SD) BECAUSE IT WAS CLOSER AND THE WX (TSTMS) WAS CONSIDERABLY BETTER IN THAT DIRECTION. AT THIS TIME WE WENT THROUGH OUR QRH (QUICK REF HANDBOOK) BUT IT DID NOT ADDRESS THIS TYPE OF MALFUNCTION. WE THEN DECLARED AN EMER AND REQUESTED THAT CRASH FIRE RESCUE BE STANDING BY. THE CAPT BRIEFED MYSELF; THE FLT ATTENDANT AND OUR FAA JUMPSEAT RIDER ON EVAC PROCS. THE CAPT AND I THEN WENT THROUGH AND COMPLETED THE DSCNT CHK WHILE OUR FLT ATTENDANT PREPARED THE CABIN FOR ARR. PRIOR TO APCH; WE SLOWED THE ACFT TO APCH SPD TO SEE HOW IT WOULD REACT AT SLOWER AIRSPDS. THE CAPT THEN LANDED WITH PARTIAL FLAPS TO MINIMIZE ELEVATOR AND ELEVATOR TRIM TRAVEL. THE LNDG WAS WITHOUT INCIDENT. THE CAPT; MYSELF AND OUR FAA JUMPSEAT RIDER POST-FLT INSPECTED THE ACFT AND DIDN'T FIND ANYTHING OUT OF THE ORDINARY. COMPANY AUTHORIZED MECHS THEN EXAMINED THE ACFT AND DETERMINED THE PROBLEM WHICH THEY BELIEVED TO BE A SCREW THAT HAD LODGED ITSELF BTWN THE ELEVATOR AND THE ELEVATOR FAIRING. THE SCREW IS BELIEVED TO HAVE FALLEN OUT FROM RIGHT ABOVE THE HORIZ STABILIZER; AN AREA WHICH ISN'T VISIBLE FROM GND LEVEL. WHILE THE MECHS WERE SEARCHING FOR THE PROBLEM THEY FOUND AN ADDITIONAL PROBLEM THAT WAS UNRELATED TO THE FIRST. THE MECHS THEN FIXED BOTH DISCREPANCIES AND SIGNED THEM OFF PER COMPANY PROC. THE CAPT AND I PERFORMED A TEST FLT; WHICH WAS SATISFACTORY; THEN FERRIED THE ACFT BACK TO MINNEAPOLIS WITHOUT FURTHER INCIDENT.