A PIPER PA34 LANDED GEAR UP DUE TO THE LNDG GEAR MOTOR CIRCUIT BREAKER TRIPPED AND THE GEAR DID NOT EXTEND. CHRONIC MAINT PROB.

Narrative

ON FEB/WED/05 AT APPROX XA50; I WAS CONDUCTING A MULTI-ENG TRAINING WITH A STUDENT. AFTER COMPLETING ALL MANEUVERS; THE STUDENT REQUESTED IF HE COULD PRACTICE SOME INST APCHS. THE STUDENT I WAS WITH HOLDS AN INST RATING. WE THEN CONTACTED APCH AND REQUESTED PERMISSION AND RECEIVED AUTH TO PRACTICE INST APCHS AT ZZZ ARPT. APCH PROCEEDED TO GIVE HDGS TO INTERCEPT LOC FOR THE ILS RWY 9R. WE FOLLOWED INSTRUCTIONS GIVEN AND PERFORMED A LOW APCH WITH MISSED APCH HDG SW. DURING THIS MANEUVER; THE STUDENT FOLLOWED ALL ESTABLISHED PROCS. WE THEN PROCEEDED TO PERFORM 1 MORE APCH. WE WERE FLYING THE LOC AT THE TIME WE INTERCEPTED THE GS; THE STUDENT PROCEEDED TO PERFORM THE LNDG CHKLIST. I WAS SUPERVISING THAT THE STUDENT WAS FOLLOWING ALL THE LNDG PROCS. THE STUDENT WAS ORALLY STATING EACH STEP OF THE CHKLIST PROCS. I OBSERVED AS HE MOVED THE MIX FORWARD; PROP FORWARD; AND LNDG GEAR DOWN AT THE SAME TIME I LOOKED FOR THE TRANSITION LIGHT. WHEN THE TRANSITION LIGHT TURNED ON; I LOOKED OUTSIDE; CHKING FOR TFC; BECAUSE WE WERE INSTRUCTED TO MAINTAIN VFR AT ALL TIMES. SIMULTANEOUSLY; WE RPTED TO ZZZ TWR THAT WE WERE IN THE OM AND THE TWR TOLD US TO PERFORM A SIDESTEP TO RWY 9L. WE BROKE THE APCH AND PROCEEDED TO RWY 9L. ON FINAL; THE STUDENT SAID GUMP CHK. THE STUDENT THEN PROCEEDED TO VERIFY THE GUMP CHK AND STATED ORALLY 'GAS; UNDERCARRIAGE; 3 GREENS; MIX AND PROP.' I WAS LOOKING FOR TFC AND WE PROCEEDED TO LAND. WHEN WE WERE ON TOP OF THE RWY; I ASKED THE STUDENT 'ARE YOU PLANNING TO LAND?' AND I REALIZED THAT THE LNDG GEAR HAD NOT COME OUT. I PROCEEDED TO CLOSE THE MIX AND FEATHER THE PROP AND HOLD FOR IMPACT. WHEN THE PLANE STOPPED; WE CHKED; AND THE CIRCUIT BREAKER WAS OUT. THAT IS WHY THE LNDG GEAR HAD NOT COME OUT. AFTER THE INCIDENT; I WAS NOTIFIED BY THE OTHER INSTRUCTOR THAT HE HAD THE SAME PROB THE DAY BEFORE BUT HE WAS ABLE TO RESET THE CIRCUIT BREAKER AND THE LNDG GEAR HAD COME DOWN. AFTERWARDS; HE CONDUCTED A TEST FLT; BUT THE PROB DID NOT OCCUR AGAIN. WE HAD THE SAME PROB WITH THIS AIRPLANE APPROX 1 YR AGO AND TOOK IT TO MAINT. THE MECHS CONDUCTED A RETRACTION AND THE PROB DID NOT RESURFACE. THEREFORE; WE CONTINUE TO FLY THE AIRPLANE AND EVERY COUPLE OF FLTS THE PROB REAPPEARED BUT EVERY TIME WE TOOK THE PLANE TO THE REPAIR SHOP AND THE RETRACTION WAS CONDUCTED; THE PROB DID NOT OCCUR AT THAT TIME. FINALLY; AFTER SEVERAL ATTEMPTS AT THE REPAIR SHOP THEY DECIDED TO CHANGE THE BRUSHES IN THE LNDG GEAR MOTOR TO SEE IF THIS WOULD FIX THE PROB. THE PROB WITH LNDG GEAR DID NOT OCCUR AGAIN UNTIL FEB/WED/05.