PA-44Seminole

Parts most often named Cylinder (12) · Pushrod (12) · Cylinder Head (9) · Exhaust Valve (3)

ENGINE WOULD RUN ROUGH AT ALL POWER SETTINGS. AFTER INSPECTION FOUND THE NR 3 CYLINDER ON THE RT ENGINE CRACKED FROM THE TOP SPARK PLUG HOLE EXTENDING AROUND TO THE BOTTOM SPARK PLUG HOLE. CRACK IS VISIBLE FROM EXTERIOR AND INTERIOR OF CYLINDER ASSY.

ENGINE HAD LOW COMPRESSION AT INSPECTION. MECHANIC FOUND BURNED EXHAUST VALVE. THE CYLINDER WAS DISASSEMBLED AND THE EXHAUST GUIDE WAS FOUND TO BE WORN BEYOND LIMITS. GUIDE WAS WORN TO .5080", MAX WEAR IS .5025". THIS IS THE THIRD LOW TIME ENGINE WE HAVE FOUND WITH WORN EXHAUST GUIDES IN THE LAST YEAR. THE CYLINDER WAS REMOVED FROM [S/N removed].

NR 3 CYLINDER HAD A CRACK FROM OUTSIDE OF CYLINDER THROUGH INTO COMBUSTION CHAMBER, APPROXIMATELY 2 INCHES INBOARD OF WHERE CYLINDER MEETS BARREL. NO INDICATIONS FROM FLIGHT CREW. A GENERAL NOISE WAS OBSERVED FROM MAINTENANCE PERSONEL DURING A ROUTINE 50 HR OIL CHANGE WHICH INCLUDED A DIFFERENTIAL CYLINDER LEAK CHECK.

Parts most often named Distributor Gear (13) · Magneto (8) · Distributor Blk (4) · Points (3)

THE MAGNETO WAS FOUND TO HAVE A LARGE AMOUNT OF GREASE ON THE CAM, ENOUGH TO EASILY SLING INTO THE POINT ASSEMBLY WHICH WOULD CAUSE THE MAGNETO TO COMPLETELY FAIL. THIS WAS AN OUT OF BOX ISSUE, NEW MAGNETO.

THE MAGNETO ROTOR SHEARED, THE MAGNETO DROPS DURING A CHECK WERE FOUND TO BE VERY HIGH. WHEN THE MAGNETO WAS REMOVED FROM THE ENGINE IT WAS FOUND THAT THE ROTOR SHAFT HAD COMPLETELY SHEARED.

IN FLIGHT, RH ENGINE SUFFERED PARTIAL OIL PRESSURE LOSS. PRECAUTIONARY LANDING MADE AT KOXB. TROUBLESHOT LOSS OF OIL PRESSURE, DETERMINED TO BE AN INTERNAL ENGINE ISSUE. REMOVED ENGINE FROM [S/N removed] AND SENT TO COLUMBIA AIRCRAFT [S/N removed] INC. FOR INSPECTION/REPAIR. CAUSE DETERMINED TO BE A CATASTROPHIC FAILURE OF THE MAGNETO IMPULSE COUPLING IN WHICH FOD DAMAGED THE OIL PUMP ASSEMBLY. NOTE: DURING A 500HR MAGNETO [S/N removed]/IMPULSE COUPLING INSPECTION; NO DEFECTS WERE NOTED AT 1083.7 HOURS MAGNETO TT. 4330

Parts most often named Elbow (11) · Tube (11) · Pipe (5) · Coupling (4)

(CAN) UNABLE TO SHUT OFF FUEL FOR EITHER TANK, O-RINGS FOUND IN PIECES IN EACH CORRESPONDING GASCOLATOR AFTER TANKS WERE DRAINED. PREVIOUS AMO HAD [S/N removed] CABLES DUE TO STIFF VALVE ACTUATION. CABLES WERE FOUND [S/N removed] AND SUSPECT STIFFNESS DUE TO DEGRADED O-RINGS. O-RINGS REPLACED PER SB USING O-RING KIT 760-504.

LEFT ENGINE IN-FLIGHT ROUGH AND SMOKE. FOUND ELECTRICAL FUEL PRIMER SOLENOID ACTIVATED AND TIME MASTER SWITCH ON. PUSH TO PRIME SWITCH AT COCKPIT INSTRUMENT PANEL SHORTED TO A CONTINUOUS CLOSED CIRCUIT. REPLACED DEFECTIVE SWITCH WITH SAME PART NUMBER. PROBLEM REPAIRED. (X)

Parts most often named Mount (27) · Cable (3) · Bolt (3) · Nut (1)

DURING THE AIRCRAFT'S FIRST 100 HOUR INSPECTION, THERE IS TASK TO RETORQUE THE ENGINE MOUNT-TO-FIREWALL BOLTS AS SPECIFIED IN MAINTENANCE MANUAL 71-00-00, FIGURE 1. DURING TORQUE CHECK, FOUND MULTIPLE NUTS UNDER-TORQUED AND ONE NUT THAT FAILED, SHEARING INTO MULTIPLE PIECES. ENGINE MOUNT-TO-FIREWALL NUT P/N MS21045-6 SHOULD BE TORQUED TO 240-270 IN. LBS. THE LH ENGINE I/B LWR NUT SHEARED BEFORE 270 IN. LBS. PICTURES ARE AVAILABLE UPON REQUEST.

DURING AIRCRAFT INSPECTION FOUND THAT THE LEFT ENGINE ALTERNATE AIR CABLE HAD CHAFED INTO THE ENGINE MOUNT REQUIRING IT TO BE SENT FOR REPAIR. THE WAY THE CABLE IS ROUTED AND SECURED FROM THE FACTORY IS WITH ADEL CLAMPS AND SILICONE UNDER THE CABLE. OVER TIME THE ADEL CLAMPS CAN BECOME LOOSE. THIS CAN RESULT IN THE CABLE RESTING ON THE ENGINE MOUNT AND CAUSE HIDDEN CHAFING UNDER THE SILICONE.

DURING ANNUAL INSPECTION FOUND THE ENGINE MOUNT TUBING HAD CHAFE DAMAGE FROM CONTACT WITH THE THROTTLE CABLE DUE TO IMPROPER ROUTING/CLAMPING OF THE CABLE.

Parts most often named Camshaft (9) · Lifter (4) · Crankcase (4) · Crankshaft (2)

PILOT REPORTED ON PREFLIGHT ENGINE RUN, THE MAP GAUGE INDICATED A 4" SPLIT AND THE LEFT ENGINE PRODUCED SMOKE. THE PILOT RETURNED TO THE APRON AND NOTED OIL LEAKING FROM COWLING. INSPECTION REVEALED THE LEFT ENGINE NR 2 CYLINDER EHXAUST PUSH ROD TUBE WAS BENT DUE TO THE VALVE STICKING CLOSED. THE DISPLACED PUSH ROD TUBE ALLOWED OIL TO LEAK FROM THE ENGINE. THE CYLINDER WAS REPLACED.

(CAN) AFTER SCHEDULED OUT OF PHASE OIL AND FILTER CHANGE GROUND RUN. NOTICED LT ENGINE PROPELLER HARD TO MOVE AND NO FORE AND AFT PLAY IN CRANKSHAFT. ENGINE REMOVED AND SENT FOR REPAIR. ENGINE SHOP REPORTED THAT BOTH HALF OF MIDDLE CRANKSHAFT BEARING CORNERS WERE FOUND BROKEN.

(CAN) DURING 100 HOUR INSPECTION, A CRACK WAS FOUND IN THE CRANKCASE BEHIND THE TOP REAR STUD OF CYLINDER NR 3 RT AFT. THE ENGINE WAS REMOVED FOR REPAIR/ O/H. TOTAL TIME ON THE ENGINE CASE IS UNKNOWN.

Parts most often named Air Box (11) · Plate (5) · Control Cable (4) · Grommet (2)

UPON VISUAL INSPECTION, FOUND THE RIGHT ENGINE CARBURETOR HEAT AIRBOX BACKPLATE (WELD) CRACKED AT TOP LEFT ATTACH POINT. CRACK WAS FOUND NEAR TOP SUPPORT BRACKET. AIRCRAFT USED DAILY FOR FLIGHT TRAINING WITH AN AVERAGE OF 100 HOURS OF FLIGHT TIME EVERY 90 DAYS.

UPON VISUAL INSPECTION, FOUND THE LEFT ENGINE CARBURETOR HEAT AIRBOX BACKPLATE (WELD) STEEL STAPLES WEARING THROUGH ALUMINUM WALL DUE TO AIR VIBRATION WHEN CARB HEAT DOOR IS FULLY DEFLECTED. SHOULD THE STAPLES WEAR THROUGH THE WALL ENTIRELY, FELT DOOR-STOP COULD BE SUCKED DIRECTLY INTO VENTURI OF CARBURETOR CAUSING AN INDUCTION BLOCKAGE AND ENGINE FAILURE. AIRCRAFT USED DAILY FOR FLIGHT TRAINING WITH AN AVERAGE OF 100 HOURS OF FLIGHT TIME EVERY 90 DAYS.

DURING A SCHEDULED INSPECTION, FOUND THE AIRBOX TO CARBURETOR MOUNTING FLANGE CRACKED HORIZONTALLY BETWEEN THE BOLT MOUNTING HOLES, UPON DISASSEMBLY FOUND THE THROTTLE CABLE MOUNTING BRACKET (86245-033) CRACKED IN THE RADIUS OF THE BRACKET MOUNTING FLANGE AND THE END CAP (86245-043) CRACKED

Parts most often named Bolt (4) · Bracket (4) · Spring (3) · Drag Link (2)

PA44 AIRCRAFT HAVE AN OUTER AND INNER SPRING THAT ASSISTS THE NOSE LANDING GEAR EXTENSION. IT IS BELIEVED THAT THE INNER SPRING (PN 67168-000) BROKE DURING FLIGHT. WHEN THE NOSE GEAR IS RETRACTED THIS SPRING IS EXTENDED. WHEN THE SPRING TANG BROKE THE SPRING CONTRACTED AND BOUND UP INSIDE THE OUTER SPRING. THIS PREVENTED THE NOSE GEAR FROM FULLY EXTENDING AND LOCKING. THIS CAUSED THE NOSE GEAR TO COLLAPSE UPON LANDING.

INSTALLED A NEW LANDING GEAR POWER PACK. PERFORMED SEVERAL GEAR SWINGS, NO DEFECTS FOUND. AIRCRAFT FLEW A FEW TRIPS, NO PROBLEMS. THE POWER PACK FAILED ON THE LAST FLIGHT. AFTER TROUBLESHOOTING THE SYSTEM, THE POWERPACK WAS INOP. INSTALLED AN EXCHANGED POWER PACK FROM THE SAME COMPANY. SWUNG THE GEAR SEVERAL TIMES, NO DEFECTS FOUND. FLIGHT CHECK OPERATION, CHECKED OK.

AFTER TAKEOFF LANDING GEAR WAS RETRACTED. IMMEDIATELY AFTER INDICATION OF GEAR UP, A GEAR WARNING WAS THEN INDICATED. AFTER LANDING IT WAS FOUND THAT THE ROD END BEARING IN THE NOSE GEAR ACTUATOR HAD BROKEN. THIS ALLOWED THE NOSE GEAR TO EXTEND AND RETURN TO A DOWN AND LOCKED POSITION.

Parts most often named Wire Harness (13) · Wire (11) · Connector (2) · Downlock Switch (2)

PILOTS REPORTED NO GEAR DOWN AND LOCKED INDICATION FOR LH MAIN LANDING GEAR. INSPECTION REVEALED BROKEN WIRES ON THE LH MAIN LANDING GEAR DOWN LOCK SWITCH.

IMMEDIATELY AFTER TAKEOFF, THE GEAR WARNING AND HYDRAULIC PUMP CIRCUIT BREAKERS TRIPPED. THE AIRCRAFT RETURNED FOR A SAFE LANDING. DURING A MAINTENANCE GEAR FUNCTIONAL TEST, THE ISSUE COULD NOT BE IMMEDIATELY DUPLICATED, WHEN THE TECH BEGAN TO CLOSELY INSPECTING THE LEFT GEAR DOWN LIMIT SWITCH, THE WIRES CAME APART. TWO MAJOR ISSUES WITH DESIGN OF THIS SWITCH.

THE WIRE BUNDLE GOING TO THE RT MLG SQUAT SWITCH WAS ROUTED INCORRECTLY. THIS SITUATION CREATED A STRESS POINT AT THE ROOT OF THE SQUAT SWITCH WHERE THE WIRES JUST START TO COME OUT. IT CAUSED THE WIRES TO BEND EVERY TIME THE GEAR WAS CYCLED EITHER UP OR DOWN. WHEN THE WIRE BUNDLE IS ROUTED CORRECTLY THIS PROBLEM DOES NOT EXIST. THIS CONTINUOUS BENDING BACK AND FORTH CAUSED THE WIRE FOR THE GEAR DOWN AND LOCKED GREEN LIGHT NOT TO ILLUMINATE WHEN THE GEAR WAS IN FACT IN THE DOWN AND LOCKED POSITION.

Parts most often named Rib (27) · Flange (1)

WHILE COMPLYING WITH PIPER SB1161D, CRACKING WAS DISCOVERED ON THE FLANGES IDENTIFIED BY THE [S/N removed] BULLETIN, ON BOTH WINGS. THE FLANGES WERE PART OF A PREVIOUSLY INSTALLED REPAIR KIT AND WERE NOT THE WING RIB'S ORIGINAL FLANGE. THE REPAIR KIT IS NOT AN ADEQUATE PERMANENT SOLUTION TO THE STRESSES CAUSING THE PART FAILURE/CRACKING.

DURING A ROUTINE INSPECTION, A NOSE RIB IN THE RIGHT WING WAS FOUND TO BE CRACKED. RIB IN QUESTION IS LOCATED AT WING STA 50.5; CRACKING WAS SEEN WHERE RIB ADJOINS WING SPAR, DIRECTLY NEXT TO ELECTRIC FUEL PUMP. CRACKING OCCURRED AT RIVET HOLES. IT IS SUSPECTED THAT CRACKING IS CAUSED BY LOADS ON LANDING GEAR TRANSFERRING TO SURROUNDING STRUCTURE, INCLUDING THIS RIB.

DURING A ROUTINE INSPECTION, A NOSE RIB IN THE LEFT WING WAS FOUND TO BE CRACKED. RIB IN QUESTION IS LOCATED AT WING STA 50.05; CRACKING WAS SEEN WHERE RIB ADJOINS WING SPAR, DIRECTLY NEXT TO ELECTRIC FUEL PUMP. CRACKING OCCURRED AT RIVET HOLES. IT IS SUSPECTED THAT CRACKING IS CAUSED BY LOADS ON LANDING GEAR TRANSFERRING TO SURROUNDING STRUCTURE, INCLUDING THIS RIB.

Parts most often named Downlock Switch (10) · Squat Switch (4) · Switch (3) · Harness (2)

PILOTS REPORTED THAT THE RIGHT GEAR DOWN/LOCKED LIGHT WOULD NOT WORK OR WAS BURNED OUT. AFTER SECOND REPORT OF MALFUNCTION, AN EXPANDED GEAR TEST WAS DONE. DURING TEST, IT WAS NOTED THAT THE LIGHT WOULD ILLUMINATE DIMLY AND FLICKER. WHEN THE GEAR WAS LOWERED AND RAISED REPEATEDLY, THE LIGHT BECAME BRIGHTER AND DID NOT FLICKER. IT APPEARS THAT THE RIGHT GEAR DOWNLOCK SWITCH, WHICH CONTROLS POSITION INDICATION, SUFFERED AN INTERNAL FAILURE.

AFTER TWO TOUCH AND GOES, THE PILOT NOTED THAT THE RIGHT MAIN LANDING GEAR WAS FAILING TO INDICATE DOWN AND LOCKED. INSPECTION REVEALED THAT THE GEAR DOWN LIMIT SWITCH HAD BROKEN WIRES.

DURING FLIGHT, THE NOSE GEAR DOWN-AND-LOCKED INDICATION WAS INTERMITTENT AND FLICKERED ON AND OFF. IT WAS DETERMINED THAT THE ISSUE WAS CAUSED BY A BROKEN WIRE IN THE NOSE GEAR DOWN LIMIT SWITCH. THIS REPAIR STATION HAS SEEN DOZENS OF ISSUES WITH DOWN LIMIT SWITCHES ON THIS ACFT TYPE, AS THE DESIGN OF THE WIRING HARNESS CAUSES WIRES TO BECOME PULLED AND FATIGUED; THE DESIGN ALSO MAKES VISUAL DETECTION OF BROKEN WIRES VERY DIFFICULT.