A PIPER PA31 ON FINAL APCH AT 800 FT AUTOPLT DISENGAGED AND PLT DISCOVERED THE ELEVATOR BINDING AND NOT MOVING SMOOTHLY. CAUSED BY LOOSE TRIM SERVO SUPPORT.

Narrative

PICKED UP ACFT (CHEYENNE) AT ZZZ1 FOR NORMAL TEST FLT FOLLOWING PHASE 1 SCHEDULED MAINT EVENT. EXCEPT FOR A FEW VERY MINOR SQUAWKS; ALL WAS NORMAL UNTIL IT DISENGAGED THE FLT DIRECTOR/AUTOPLT ABOUT 800 FT AGL ON FINAL APCH TO THE ILS RWY 23 AT ZZZ IN VISUAL CONDITIONS. AT THAT TIME; IT BECAME APPARENT THAT THE ELEVATOR CTL WAS BINDING AND NOT MOVING SMOOTHLY OR EASILY. TRIM APPEARED TO BE LOCKED UP AS WELL. I JUDGED IT WOULD BE BEST TO CONTINUE A STABILIZED APCH WITH THE CURRENT ELEVATOR SETTING AND TO ALTER THE FLT PATH (VERT) WITH FLAP SETTINGS AND ENG PWR. THIS WORKED WELL; DESPITE GUSTY WINDS (+20 KTS) AND XWIND COMPONENT WITH +/-15 KTS AND WINDSHEAR LAST 600 FT AGL. AT MOMENT OF FLARE; INCREASED PWR TO RAISE NOSE AND USED ELEVATOR MOVEMENT; AS AVAILABLE; BUT LIMITED. NO DAMAGE; NORMAL TOUCHDOWN. NO EMER DECLARED DUE TO SHORT TIME BTWN CTL BINDING AND TOUCHDOWN. ACFT HAD BEEN CAREFULLY PREFLTED WITHOUT ANY EVIDENCE OF ELEVATOR PROB. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE AIRPLANE WAS ON A TEST FLT AFTER COMPLETION OF SCHEDULED MAINT. THE RPTR SAID THE AUTOPLT DISCONNECTED ON FINAL APCH AND IT WAS DISCOVERED THE ELEVATOR CTL WAS BINDING. THE RPTR STATED THE LNDG WAS MADE BY USING WHAT ELEVATOR CTL WAS AVAILABLE AND ADDING PWR TO RAISE THE NOSE. THE RPTR SAID THE TAIL WAS OPENED UP BY MAINT AND IT WAS FOUND THAT WHEN A TORQUE TUBE HAD BEEN REPLACED THE ELEVATOR TRIM SERVO SUPPORT WAS NOT SECURED AND HAD JAMMED THE ELEVATOR CABLE. THE RPTR STATED THE FLT CTL CHK PRIOR TO TKOF WAS NORMAL WITH NO BINDING.