170170A · 170B

Parts most often named Cylinder (4) · Lifter (1) · Pin (1)

NUMBER 3 CYLINDER FAILED. IT CAME APART ABOUT 1 1/2 INCHES UP FROM THE BASE. CYLINDER WAS FIRST INSTALLED ON 6-9-1997 AND RECONDITIONED AT 495 HOURS ON 6/2000. IT HAD 1686 HOURS SINCE NEW WHEN IT FAILED 4/2016.

(CAN) CYLINDER BARREL CRACK BETWEEN FIN 9& 10 70%. UNSCHEDULED LANDING. ENGINE SHUT DOWN. CYLINDER RETURNED TO MANUFACTURER FOR ASSESSMENT.

FOUND METAL PARTICLES IN OIL SCREEN AT 30 HOURS AND AGAIN AT 74 HOURS. FOUND CYLINDERS COMING APART INSIDE BORE. PIECES MEASURED .4 X .3 INCHES.

Parts most often named Control Cable (2) · Pedal (1) · Bellcrank (1) · Bracket (1)

PILOT REPORTED RUDDER FROZEN IN FLT. UNEVENTFUL LANDING. MAINTENANCE INITIALLY CONFIRMED THE RUDDER COULD NOT BE MOVED, THEN IT FREED UP. REMOVED CARGO COMPARTMENT FLOOR AT CARGO DOOR AND OBSERVED WATER FROZEN AROUND RUDDER CABLE PULLEYS AT FUSELAGE STA 495. REMOVED WATER AFTER THAWING. THIS IS THE SECOND INCIDENT OF THIS NATURE ON THIS AIRCRAFT TYPE THAT WE HAVE EXPERIENCED.

(CAN) DURING THE ANNUAL INSPECTION, THE RUDDER CABLES WERE FOUND CORRODED AND FRAYED WHERE THEY PASS THROUGH THE TAILCONE AREA. THE SUBMITTER STATES THAT THIS AREA IS DIFFICULT TO INSPECT THOROUGHLY WITHOUT DISASSEMBLY OF THE TAIL SECTION.

RUDDER PEDALS WERE REMOVED TO FACILITATE OTHER MAINTENANCE. UPON REMOVAL, FOUND PEDAL ATTACH HOLES SEVERELY ELONGATED. TO REPAIR, A .125 INCH DOUBLER OF 6061-T6 WAS USED ON EACH SIDE OF THE PEDAL AS THE PEDAL PIN WAS JUST LONG ENOUGH TO ACCOMODATE THE EXTRA THICKNESS. ALL 4 PEDALS WERE DAMAGED IN THIS WAY. SUSPECT CAUSE, 48 YEARS OF FLIGHT. RECOMMEND PERIODIC INSPECTION ON OLDER AIRCRAFT.

Parts most often named Wheel (1) · Bracket Assy (1) · Spring (1) · Leg Assy (1)

NOSE LANDING GEAR LEG BROKEN AT FORWARD WELD ON SHOCK ABSORBER ATTACHMENT BRACKET. EXISTING INTERNAL CRACK. PROBABLE CAUSE, BAD WELD. (K)

WHILE REMOVING AIRCRAFT FROM HANGAR, TAIL WHEEL SWIVELED AND ASSY SEPARATED FROM BRACKET AND SPRING ASSY. AFTER INVESTIGATING, FOUND BOLT IN THE BRACKET ASSY WAS PARTLY FRACTURED AND THE SUDDEN JOLT FROM THE SWIVEL BROKE THE TAIL WHEEL ASSY OFF THE AIRCRAFT. SUBMITTER SUGGESTS ALL TAIL WHEEL BRACKET ASSYS BE REMOVED, INSPECTED, AND DYE-PENETRANT BOLTS FOR CRACKS.

Parts most often named Stringer (3)

CRACKED AT FORWARD END AND PROGRESSES AFT. PROP STRIKE, OUT OF BALANCE PROP. EXAMPLE FROM C-170B WITH THE ENGINE INSTALLED. (K)

CRACKED AT FWD END AND PROGRESSES AFT. PROP STRIKE, OUT OF BALANCE PROP? AIRCRAFT HAS A HISTORY OF WING REPAIRS FROM GROUND LOOPS BUT HAS SINCE HAD A ENGINE UPGRADE TO MFG. (K)

Parts most often named Skin (3)

UPON INSPECTION, A 3 INCH CRACK WAS DISCOVERED AFT OF THE LEFT LANDING GEAR LEG ADJACENT TO THE GEARBOX. WAS DIFFICULT TO SEE, DUE TO CLOSE PROXIMITY TO OVERLAPPING EXTERIOR GEARBOX SKIN. WOULD RECOMMEND USE OF LIGHT BELOW FUSELAGE WHILE INSPECTING THROUGH CABIN FLOOR PANELS.

REAR BULKHEAD WAS FOUND CRACKED AT THE TAIL WHEEL MOUNTING SHEAR BRACKET. THE SKIN ON BOTH SIDES OF THE TAIL WHEEL MOUNTING BRACKET WERE FOUND CRACKED UPON DISASSEMBLY WITH CORROSION BETWEEN THE BRACKET AND SKIN. SUSPECT CAUSE WAS THE WEARING OF THE SKIN BY THE CORROSION. THE OLD STYLE TAIL WHEEL BRACKET IS STEEL, THE NEW ONE IS ALUMINUM. THIS SHOULD PREVENT THE DISSIMILAR METAL CORROSION WHICH MAY HAVE CAUSED THE PROBLEM. NOTE: THE PART WAS 44 YEARS OLD.

Parts most often named Cylinder (1) · Brakes (1) · Line (1)

STC SA13GL INSTALLATION. IN BOTH BRAKE ASSEMBLIES, 30-63A, THE 091-02200 CYLINDER ASSEMBLIES WERE FOUND TO BE CRACKED ACROSS AND PARALLEL TO THE 069-00400 ANCHOR BOLT HOLE. THIS IS THE SECOND AIRCRAFT, FOUND WITH CRACKS IN THE 091-02200 CYLINDER ASSEMBLIES. THIS AREA IS READILY ACCESSIBLE AND SHOULD BE PART OF THE PREFLIGHT INSPECTION. THE CRACKS ARE EASILY SEEN, WHEN LOOKING FOR THEM. (K)

THE AIRCRAFT NOSED OVER ON LANDING CAUSED BY BOTH BRAKES BEING LOCKED ON TOUCHDOWN. PRIOR TO LANDING (SHORT FINAL) THE PILOT HAD TO USE FULL RUDDER DEFLECTION. WHEN THE AIRCRAFT TOUCHED DOWN THE AIRPLANE NOSED OVER. THE BRAKES WERE FOUND LOCKED, WHEN FULL RUDDER TRAVEL USED, THE LOCKPLATE CONTACTS THE FIREWALL AND LOCKS THE BRAKES. SUBMITTER STATED THIS IS A KNOWN CONDITION, BUT NO AD HAS BEEN ISSUED.

Parts most often named Bracket (2) · Mount (1)

(CAN) LT UPPER ENGINE MOUNT BRACKET AFT OF FIREWALL EXTREME CORROSION (HALF OF BRACKET MISSING) VERY DIFFICULT TO SEE DUE TO INSULATION COVERING ON FIREWALL.

BRACKET BROKEN AT THE EDGE OF THE STRAIGHT LINE OF BOLT PAD MACHINED SURFACE. SUBMITTER RECOMMENDED VISUAL INSPECTION EVERY 100 HOURS.

Parts most often named Tunnel (1) · Eyebolt (1)

FLOAT EQUIPPED, LIFTING EYES WERE INSTALLED IN THE WRONG POSITION. RESULTING IN DRILLING THROUGH THE MAIN FORWARD WING SPAR AND LEAVING APPROXIMATELY EDGE DISTANCE. BETWEEN THE FORWARD SPAR ATTACH BOLT AND EDGE OF SPAR. (EYES SHOULD BE INSIDE CABIN TOP RIVET LINE) (K)

CABIN HEAT DUCT TUBING LEADING FROM THE FIREWALL TO THE REAR SEAT HEAT IS CAUSING SEVERE CORROSION IN THE CABIN TUNNEL INTERIOR. THIS TUNNEL SUPPORTS THE YOKE ASSEMBLY, TRIM WHEEL, AND FLAP LEVER. RECOMMEND REPLACING ALL INTERIOR DUCT TUBING WITH MODERN SILICONE CAT OR SCAT, INSPECT FOR CORROSION.

Parts most often named Bracket (2)

UPON INSPECTION OF LANDING GEAR, LT SIDE DUE TO HARD LANDING, FOUND BRACKET CRACKED AND CORRODED BEYOND TREATMENT OR REPAIR. DUE TO CORROSION, RT SIDE WAS ALSO CORRODED BEYOND TREATMENT OR REPAIR. REPLACED BOTH LT AND RT SIDES. SUBMITTER RECOMMENDS INSTALLING DRAIN HOLES TO PREVENT BULKHEAD FROM HOLDING MOISTURE AND FREQUENT INSPECTION.

Parts most often named Bracket Assy (1) · Bracket (1)

TAIL WHEEL SEPARATED FROM AIRCRAFT. INVESTIGATION FOUND ASSY HAD SEPARATED DUE TO BROKEN BOLT. BOLT HAD BEEN DYE CHECKED AT LAST ANNUAL DUE TO REPORT OF ANOTHER AIRCRAFT WITH BROKEN BOLT. THE BOLT CRACK DID NOT SHOW UP ON A DYE CHECK. SUBMITTER RECOMMENDED TO NDT X-RAY OR EDDY CURRENT CHECK.

BRACKET ASSY BOLT APPEARS AS METAL HAS CRYSTALLIZED THROUGH AGE. BOLT THEN SHEARED ALLOWING TAILWHEEL TO FALL OFF AIRCRAFT ON TAKEOFF.