MIL2ATP, INC.

WHILE ON FINAL APPROACH, THE PILOT REPORTED A LOSS OF MANIFOLD PRESSURE WITH THE RIGHT ENGINE. IT WAS FOUND THAT THERE WAS A HOLE APPROX 1.5 X 3.0 INCHES IN THE RIGHT ENGINE EXHAUST, MOST SPECIFICALLY FOCUSED AROUND THE NR 3 CYLINDER EXHAUST PIPE. THE EXHAUST STACK ASSEMBLY WAS REPLACED.

DURING THE COURSE OF COMPLETING A 100-HOUR INSPECTION, A CRACK WAS DISCOVERED IN THE FORWARD PORTION OF RIB, CESSNA P/N 0822175-79. THE RIB HAD BEEN MODIFIED IAW CESSNA SK 414-8E APPROXIMATELY 4,303 HOURS AGO, WHICH, BY LOCATION, IS NOT ASSOCIATED WITH THE CRACK SHOWN IN THE DRAWING.

DURING THE COURSE OF COMPLETING A 100-HOUR INSPECTION, A CRACK WAS DISCOVERED IN THE FORWARD PORTION OF RIB, CESSNA P/N 0822175-74. THE RIB HAD BEEN MODIFIED IAW CESSNA SK 414-8E APPROXIMATELY 4,303 HOURS AGO, WHICH, BY LOCATION, IS NOT ASSOCIATED WITH THE CRACK SHOWN IN THE DRAWING.

DURING THE COURSE OF NORMAL FLIGHT, THE PILOT NOTICED RIGHT ENGINE RUNNING ROUGH WITH A DROP IN ITS MANIFOLD PRESSURE. THE AIRCRAFT LANDED WITHOUT EVENT. MAINTENANCE WAS ABLE TO DETERMINE THAT THE NR 2 CYLINDER HEAD HAD SEPARATED FROM THE BARREL OF THE CYLINDER. THE DAMAGE WAS CONFINED TO THE CYLINDER, THE UPPER DECK LINES, INJECTOR LINES, INTAKE AND EXHAUST PIPES WERE ALL UNDAMAGED.

DURING THE COURSE OF COMPLETING A 100-HOUR INSPECTION, MULTIPLE CRACKS WERE FOUND IN THE PRIMARY COMPONENTS THAT MAKE UP CESSNA SERVICE KIT SK414-83. CRACKS WERE FOUND ON BOTH LEFT AND RIGHT RIBS, FILLERS, DOUBLERS, AND ANGLES.

DURING THE COURSE OF COMPLETING A 100-HOUR INSPECTION, MULTIPLE CRACKS WERE FOUND IN THE PRIMARY COMPONENTS THAT MAKE UP CESSNA SERVICE KIT SK404-83. CRACKS WERE FOUND ON BOTH LEFT AND RIGHT RIBS, FILLERS, DOUBLERS, AND ANGLES.

THE PILOT STATED HE HEARD A FUNNY NOISE WHEN LANDING GEAR WAS RETRACTED. WHEN LANDING GEAR WAS EXTENDED TO LAND, DID NOT GET A SAFE INDICATION ON LT MAIN GEAR. UPON LANDING, ACFT SETTLED ON ITS GEAR, ROLLED SEVERAL FEET AND THE LT GEAR CAME OFF OF THE ACFT. THE ROLL PIN (NAS561P4-28) THAT RETAINS THE UPPER TRUNNION PIVOT PIN (0841011-1) IN PLACE HAD SHEARED ALLOWING THE PIVOT PIN TO MOVE FORWARD WHICH ALLOWED THE GEAR TO COME OFF OF THE ACFT.

DURING 100-HOUR INSPECTION, MECHANIC NOTICED RIGHT ENGINE, NR 6 CYLINDER, PER MOST AFT AND THE LOWER TWO MOST AFT STUDS HAD BROKEN OFF FLUSH WITH THE CYLINDER BASE/SKIRT. THE CASE WAS INSPECTED FOR CRACKS, AND A CRACK APPROXIMATELY A .50 INCH LONG WAS OBSERVED COMING FROM THE LOWER STUD HOLE (JUST FORWARD OF THE MOST AFT LOWER STUD) WAS CRACKED IN THE DIRECTION OF THE CENTER OF THE ENGINE CASE. SUBMITTER STATED TO HAVING HAD THIS PROBLEM IN THE PAST AND HAD STARTED REPLACING THE CYLINDER BASE STUDS AT ENGINE OVERHAUL. UNFORTUNATELY, THESE STUDS WERE REPLACED AND HAVE APPROXIMATELY 300 HOURS TISN.

WHILE READING THE ACFT HOUR METER, A STRONG FUEL SMELL WAS NOTICED. A FUEL STAIN WAS NOTICED UNDER THE LEFT WING STARTING AT THE INBD ENGINE NACELLE AND SEEPING DOWN THE MAIN WING SPAR TO THE INBD MAIN GEAR DOOR. CROSS-FEED FUEL LINE HAD BEEN CHAFED AFT OF THE TURBOCHARGER BY A STRINGER AND WAS LEAKING. UNFORTUNATELY, THESE LINES MAINTAIN A POSITIVE PRESSURE ON THEM WITH NO WAY TO TURN OFF THE FUEL. IT IS SUBMITTER'S RECOMMENDATION THAT CESSNA PROVIDE SOME MEANS TO ENABLE THE PILOT TO TURN OFF THE FUEL SUPPLY TO THESE FUEL LINES.

WHILE TAXIING IN, THE PILOT HEARD A 'POPPING' NOISE IN THE NOSE LANDING GEAR AREA. A CLOSE INSPECTION REVEALED A BROKEN ADJUSTING BELLCRANK (CESSNA P/N 0842104-2). THE BELLCRANK WAS BROKEN WHERE THE WHEEL WELL ACTUATING ROD IS ATTACHED. SUBMITTER STATED UNABLE TO TELL WHAT CAUSED THIS BREAK. THE BREAK APPEARS TO BE A FRESH, CLEAN, NEW BREAK AND THE GEAR DOES NOT SHOW ANY SIGNS OF STRESS.

DURING THE COURSE OF A 100-HOUR INSPECTION, THE MECHANIC NOTICED THE LEFT ENGINE, NR 1 CYLINDER, MOST FORWARD UPPER STUD HAD BROKEN OFF FLUSH WITH THE CYLINDER BASE/SKIRT. THE CYLINDER WAS REMOVED AND THE CASE WAS INSPECTED FOR CRACKS AND ANY SIGNS OF CHAFING. NONE WAS FOUND. IT IS SUSPECTED THAT TIME IN SERVICE IS THE MAIN CAUSE FOR BREAKAGE OF THE STUD. NO WAY TO DETERMINE THE TOTAL TIME OF THIS STUD OR THE CRANKCASE DUE TO THE REMOVAL OF THE DATA PLATE DURING THE OVERHAUL/CRANKCASE RECERTIFICATION PROCESS.

DURING THE COURSE OF A 100-HOUR INSPECTION, THE MECHANIC NOTICED A SIZEABLE AMOUNT OF OIL ON THE TOP LEFT PORTION OF THE ENGINE CASE. A CLOSER INSPECTION REVEALED A CRACK APPROXIMATELY 1.6250 INCH LONG EMITTING FROM THE 9TH BACKBONE BOLT (COUNTING FROM FRONT TO BACK). THE CRACK/CASE WAS INSPECTED IAW TCM SBM90-17 AND WAS DETERMINED TO BE UNAIRWORTHY DUE TO THE AMOUNT OF OIL LEAKING FROM SAID CRACK/CASE. THE CASE IN QUESTION HAS NOT BEEN REPAIRED/WELDED IN THE AREA AROUND THE CRACK. (THE CASE IS THE 'HEAVY' - 7TH STUD VERSION).

WHILE REPAIRING AN UNRELATED ITEM, THE MECHANIC NOTICED A CRACK APPROXIMATELY ONE INCH LONG (RUNNING TOP TO BOTTOM) ASSOCIATED WITH THE MOST FORWARD UPPER THROUGH-STUD ON THE NR 4 CYLINDER. THE CASE WAS INSPECTED IAW TCM SB M90-17 AND DETERMINED TO BE UNAIRWORTHY BY THE LOCATION OF THE CRACK. THE CASE HAD BEEN REPAIRED AT SOME TIME IN THE PAST IN LOCATION OF THE CRACK. SUBMITTER SUGGESTED A POSSIBLE CAUSE FOR THE CRACK COULD BE FROM STRESS CAUSED BY THE REPAIR OR POSSIBLY IMPROPER HEAT TREATING TO THE SURROUNDING AREA OF REPAIR.

DURING THE COURSE OF NORMAL OPERATION, PILOT NOTICED LEFT ENGINE RUNNING ROUGH. AFTER LANDING, MAINTENANCE DETERMINED THE LEFT MAGNETO HARNESS, NR 5 CYLINDER, BOTTOM LEAD, HAD SHORTED INTERNALLY CAUSING THE SPARK PLUG TO NOT FUNCTION PROPERLY.

DURING A 100-HOUR INSPECTION, THE MECHANIC NOTICED A TEAR IN THE RIGHT SIDE OF THE NOSE GEAR WHEELWELL SKIN UNDER THE DOWNLOCK HINGE BRACKET (CESSNA BRACKET PART 0842105-2). THE DOUBLER THAT ATTACHES TO THE SKIN/BRACKET ASSEMBLY (DOUBLER CESSNA PART 5213045-2) WAS ALSO CRACKED/BROKEN. SUBMITTER STATED THIS PROBLEM IS MOST COMMONLY FOUND ON THE LEFT SIDE, THE ABOVE MENTIONED BRACKET ON THE LEFT SIDE ACTUATES OR CYCLES THE GEAR. THE PROBLEM COULD BE ASSOCIATED WITH ICE BUILDING (OR FORMING) ON THE LEADING EDGES OF GEAR DOORS CAUSING A PARTIAL BIND WHEN TRYING TO CYCLE THE GEAR.

DURING A 100-HOUR INSPECTION, MECHANIC FOUND THE RIGHT TURBO MOUNTING BRACKET BROKEN. CESSNA BRACKET 0851139-3 HAD ITS OUTBOARD LOWER ATTACH LEG BROKEN OFF. UNABLE TO DETERMINE THE CAUSE OF THIS PROBLEM.

DURING NORMAL FLIGHT, PILOT NOTICED LEFT ENGINE RUNNING ROUGH AND RETURNED TO POINT OF DEPARTURE. DETERMINED THE NR 1 CYLINDER ON THE LEFT ENGINE HAD SEPARATED THE HEAD FROM THE BARREL. SUBMITTER SUGGESTED FROM PAST EXPERIENCE, THIS IS TYPICAL OF A TCM TSIO520 CYLINDER AND STATES THE ONLY COURSE OF ACTION THAT CAN BE TAKEN IS THOROUGH 50/100 HOUR INSPECTIONS.

DURING THE COURSE OF NORMAL FLIGHT, THE PILOT NOTICED THE RIGHT TACHOMETER HAD QUIT OPERATING. IT WAS DETERMINED THE DOWEL PIN (TCM PART 535634) ON THE OIL PUMP SHAFT GEAR (TCM PART 631075) THAT DRIVES THE TACHOMETER GENERATOR WAS SHEARED. SHORTLY AFTER THE SHAFT GEAR/DOWEL PIN ASSEMBLY WAS REPLACED, THE SHAFT ON THE TACHOMETER GENERATOR SHEARED. IT IS SUSPECTED THE TACHOMETER GENERATOR HAD TEMPORARILY FAILED CAUSING THE POSSIBLY WEAKENED DOWEL PIN TO SHEAR RATHER THAN THE TACHOMETER GENERATOR SHAFT.

DURING THE COURSE OF A NORMAL PRE-FLIGHT INSPECTION, THE PILOT NOTICED LEFT SPINNER WAS LOOSE. UPON CLOSER INSPECTION, NOTICED THE BULKHEAD ATTACH HOLES WERE WALLOWED OUT THAT ATTACH THAT UNIT TO THE SLIP RING ASSEMBLY. IT IS SUSPECTED THAT WHILE THE ATTACHING SCREWS WERE STILL SAFETY WIRED TOGETHER, THEY MUST HAVE BECOME LOOSE OVER TIME WHICH ALLOWED THE HOLES TO BECOME WALLOWED OUT.

UPON COMPLETING A NORMAL TRIP, THE PILOT ON HIS POST FLIGHT INSPECTION NOTICED THE RT INBOARD LANDING GEAR DOOR WAS OPEN. AFTER A CLOSER INSPECTION, DETERMINED THE BELLCRANK ASSEMBLY THAT ACTUATES THE INBOARD GEAR DOOR WAS BROKEN. IT WAS BROKEN IN SUCH A WAY THAT THE ONLY SYSTEM AFFECTED WAS THE GEAR DOOR. THE PART WAS SHOWING SIGNS OF BEING CRACKED FOR SOME TIME, THE PART APPEARS TO BE CONSTRUCTED OF 'CAST' STEEL, AND THERE WAS A DARKER PORTION APPROXIMATELY ONE-THIRD THE LENGTH OF THE BREAK INDICATING IT WAS AN OLD CRACK. THE PART RESTS BEHIND A BRACKET WHICH MAKES IT DIFFICULT TO INSPECT.

DURING 50-HOUR INSPECTION, MECH TURNED PROP AND NOTICED A 'HISSING' SOUND EMITTING FROM NR 4 CYLINDER ON LT ENGINE. UPON CLOSER INSP, THE HISS WAS DETERMINED TO BE COMING FROM THE CHT PROBE HOLE. SLIGHT SIGNS OF SOOT IN AREA. CYLINDER CHECKED WITH DIFFERENTIAL PRESS GAUGE, FOUND 30/80 HEAVY LEAKAGE THROUGH THE CHT PROBE HOLE. SUSPECT CAUSE: AFTER CYL REMOVED, APPLIED AIR PRESS TO OUTSIDE OF PROBE HOLE, DETERMINED PROBE HOLE BOTTOM LOCATED WHERE CYL HEAD ATTACHES TO BARREL, AND EITHER THE PROBE HOLE DRILLED TOO DEEP OR INSIDE OF HEAD GIVEN TOO MUCH CLEARANCE PRIOR TO ASSY.

AFTER HAVING PROBLEMS WITH ANOTHER 400 SERIES ACFT, INSPECTED AFT ATTACH POINT OF TIP TANKS. DISCOVERED THE MOST AFT WING SKIN CRACKED AND HORIZ RIVETS SHEARED THAT ATTACH THE OTBD AILERON BRACKET ASSY (CESSNA P/N 521001-12) WHICH ARE SAME RIVETS THAT ATTACH TIP TANK AFT SUPPORT BRACKETS (CESSNA P/N 08222600-29 AND -30) TO THE WING. LT SIDE ALSO CRACKED MOST OTBD RIB (CESSNA P/N 0822040-17) AND THE MOST AFT TIP TANK SUPPORT BULKHEAD (CESSNA P/N 0823400-63, SUBASSY OF 823400-109) HAD 2 CRACKS. RIGHT DID NOT REFLECT ANY DAMAGE TO STRINGER (MOST AFT POINT) OF TIP TANK, HOWEVER, LT SIDE HAD STRUCK SOLID OBJECT AT SOME POINT.

AFTER HAVING PROBLEMS WITH ANOTHER 400 SERIES ACFT, INSPECTED AFT ATTACH POINT OF TIP TANKS. DISCOVERED THE MOST AFT WING SKIN CRACKED AND HORIZ RIVETS SHEARED THAT ATTACH THE OTBD AILERON BRACKET ASSY (CESSNA P/N 521001-12) WHICH ARE SAME RIVETS THAT ATTACH TIP TANK AFT SUPPORT BRACKETS (CESSNA P/N 08222600-29 AND -30) TO THE WING. LT SIDE ALSO CRACKED MOST OTBD RIB (CESSNA P/N 0822040-17) AND THE MOST AFT TIP TANK SUPPORT BULKHEAD (CESSNA P/N 0823400-63, SUBASSY OF 823400-109) HAD 2 CRACKS. RIGHT DID NOT REFLECT ANY DAMAGE TO STRINGER (MOST AFT POINT) OF TIP TANK, HOWEVER, LT SIDE HAD STRUCK SOLID OBJECT AT SOME POINT.

AFTER HAVING PROBLEMS WITH ANOTHER 400 SERIES ACFT, INSPECTED AFT ATTACH POINT OF TIP TANKS. DISCOVERED THE MOST AFT WING SKIN CRACKED AND HORIZ RIVETS SHEARED THAT ATTACH THE OTBD AILERON BRACKET ASSY (CESSNA P/N 521001-12) WHICH ARE SAME RIVETS THAT ATTACH TIP TANK AFT SUPPORT BRACKETS (CESSNA P/N 08222600-29 AND -30) TO THE WING. LT SIDE ALSO CRACKED MOST OTBD RIB (CESSNA P/N 0822040-17) AND THE MOST AFT TIP TANK SUPPORT BULKHEAD (CESSNA P/N 0823400-63, SUBASSY OF 823400-109) HAD 2 CRACKS. RIGHT DID NOT REFLECT ANY DAMAGE TO STRINGER (MOST AFT POINT) OF TIP TANK, HOWEVER, LT SIDE HAD STRUCK SOLID OBJECT AT SOME POINT.

AFTER HAVING PROBLEMS WITH ANOTHER 400 SERIES ACFT, INSPECTED AFT ATTACH POINT OF TIP TANKS. DISCOVERED THE MOST AFT WING SKIN CRACKED AND HORIZ RIVETS SHEARED THAT ATTACH THE OTBD AILERON BRACKET ASSY (CESSNA P/N 521001-12) WHICH ARE SAME RIVETS THAT ATTACH TIP TANK AFT SUPPORT BRACKETS (CESSNA P/N 08222600-29 AND -30) TO THE WING. LT SIDE ALSO CRACKED MOST OTBD RIB (CESSNA P/N 0822040-17) AND THE MOST AFT TIP TANK SUPPORT BULKHEAD (CESSNA P/N 0823400-63, SUBASSY OF 823400-109) HAD 2 CRACKS. RIGHT DID NOT REFLECT ANY DAMAGE TO STRINGER (MOST AFT POINT) OF TIP TANK, HOWEVER, LT SIDE HAD STRUCK SOLID OBJECT AT SOME POINT.

AFTER HAVING PROBLEMS WITH ANOTHER 400 SERIES ACFT, INSPECTED AFT ATTACH POINT OF TIP TANKS. DISCOVERED THE MOST AFT WING SKIN CRACKED AND HORIZ RIVETS SHEARED THAT ATTACH THE OTBD AILERON BRACKET ASSY (CESSNA P/N 521001-12) WHICH ARE SAME RIVETS THAT ATTACH TIP TANK AFT SUPPORT BRACKETS (CESSNA P/N 08222600-29 AND -30) TO THE WING. LT SIDE ALSO CRACKED MOST OTBD RIB (CESSNA P/N 0822040-17) AND THE MOST AFT TIP TANK SUPPORT BULKHEAD (CESSNA P/N 0823400-63, SUBASSY OF 823400-109) HAD 2 CRACKS. RIGHT DID NOT REFLECT ANY DAMAGE TO STRINGER (MOST AFT POINT) OF TIP TANK, HOWEVER, LT SIDE HAD STRUCK SOLID OBJECT AT SOME POINT.

AFTER HAVING PROBLEMS WITH ANOTHER 400 SERIES ACFT, INSPECTED AFT ATTACH POINT OF TIP TANKS. DISCOVERED THE MOST AFT WING SKIN CRACKED AND HORIZ RIVETS SHEARED THAT ATTACH THE OTBD AILERON BRACKET ASSY (CESSNA P/N 521001-12) WHICH ARE SAME RIVETS THAT ATTACH TIP TANK AFT SUPPORT BRACKETS (CESSNA P/N 08222600-29 AND -30) TO THE WING. LT SIDE ALSO CRACKED MOST OTBD RIB (CESSNA P/N 0822040-17) AND THE MOST AFT TIP TANK SUPPORT BULKHEAD (CESSNA P/N 0823400-63, SUBASSY OF 823400-109) HAD 2 CRACKS. RIGHT DID NOT REFLECT ANY DAMAGE TO STRINGER (MOST AFT POINT) OF TIP TANK, HOWEVER, LT SIDE HAD STRUCK SOLID OBJECT AT SOME POINT.

DURING THE COURSE OF A NORMAL FLIGHT, PILOT NOTICED OIL LEAK ON LEFT ENGINE. AFTER FLIGHT, REMOVED ENGINE COWLING AND SAW 5 CYLINDER STUDS HAD BROKEN ON THE NR 1 CYLINDER. ON ENGINES OPERATED ON 1600 TBO'S, SUSPECT TIME IN SERVICE IS THE MAIN CAUSE FOR BREAKAGE. PLEASE NOTE: THIS IS NOT A 7TH STUD TYPE CASE, HOWEVER, IT IS A 'HEAVY' CASE.

DURING A 100 HOUR INSPECTION, MECHANIC NOTICED CRACK IN THE WING SKIN IN MOST AFT OTBD SECTION OF LT WING. MECHANIC ALSO OBSERVED 2 RIVETS SHEARED THAT ATTACH THE OTBD AILERON HINGE BRACKET ASSY (CESSNA P/N 5021002-12) WHICH ARE SAME RIVETS THAT ATTACH THE TIP TANK SUPPORT BRACKETS (CESSNA P/N'S 0822600-29 AND -30 TO THE WING. THE MOST OTBD WING RIB WAS ALSO CRACKED IN THE MOST AFT LOWER SECTION (CESSNA P/N 0822040-17). TIP TANK STINGER (MOST AFT POINT) HAS SOME SLIGHT DAMAGE AS THOUGH IT STRUCK A SOLID OBJECT. AMOUNT OF WEIGHT WITH A FULL TANK OF FUEL BOUNCING ON THE TIP OF THE WING COULD ALSO BE A CONTRIBUTING FACTOR.

DURING A 100 HOUR INSPECTION, MECHANIC NOTICED CRACK IN THE WING SKIN IN MOST AFT OTBD SECTION OF LT WING. MECHANIC ALSO OBSERVED 2 RIVETS SHEARED THAT ATTACH THE OTBD AILERON HINGE BRACKET ASSY (CESSNA P/N 5021002-12) WHICH ARE SAME RIVETS THAT ATTACH THE TIP TANK SUPPORT BRACKETS (CESSNA P/N'S 0822600-29 AND -30 TO THE WING. THE MOST OTBD WING RIB WAS ALSO CRACKED IN THE MOST AFT LOWER SECTION (CESSNA P/N 0822040-17). TIP TANK STINGER (MOST AFT POINT) HAS SOME SLIGHT DAMAGE AS THOUGH IT STRUCK A SOLID OBJECT. AMOUNT OF WEIGHT WITH A FULL TANK OF FUEL BOUNCING ON THE TIP OF THE WING COULD ALSO BE A CONTRIBUTING FACTOR.

DURING A 100 HOUR INSPECTION, MECHANIC NOTICED CRACK IN THE WING SKIN IN MOST AFT OTBD SECTION OF LT WING. MECHANIC ALSO OBSERVED 2 RIVETS SHEARED THAT ATTACH THE OTBD AILERON HINGE BRACKET ASSY (CESSNA P/N 5021002-12) WHICH ARE SAME RIVETS THAT ATTACH THE TIP TANK SUPPORT BRACKETS (CESSNA P/N'S 0822600-29 AND -30 TO THE WING. THE MOST OTBD WING RIB WAS ALSO CRACKED IN THE MOST AFT LOWER SECTION (CESSNA P/N 0822040-17). TIP TANK STINGER (MOST AFT POINT) HAS SOME SLIGHT DAMAGE AS THOUGH IT STRUCK A SOLID OBJECT. AMOUNT OF WEIGHT WITH A FULL TANK OF FUEL BOUNCING ON THE TIP OF THE WING COULD ALSO BE A CONTRIBUTING FACTOR.

DURING A 100 HOUR INSPECTION, MECHANIC NOTICED CRACK IN THE WING SKIN IN MOST AFT OTBD SECTION OF LT WING. MECHANIC ALSO OBSERVED 2 RIVETS SHEARED THAT ATTACH THE OTBD AILERON HINGE BRACKET ASSY (CESSNA P/N 5021002-12) WHICH ARE SAME RIVETS THAT ATTACH THE TIP TANK SUPPORT BRACKETS (CESSNA P/N'S 0822600-29 AND -30 TO THE WING. THE MOST OTBD WING RIB WAS ALSO CRACKED IN THE MOST AFT LOWER SECTION (CESSNA P/N 0822040-17). TIP TANK STINGER (MOST AFT POINT) HAS SOME SLIGHT DAMAGE AS THOUGH IT STRUCK A SOLID OBJECT. AMOUNT OF WEIGHT WITH A FULL TANK OF FUEL BOUNCING ON THE TIP OF THE WING COULD ALSO BE A CONTRIBUTING FACTOR.

DURING A 100 HOUR INSPECTION, MECHANIC NOTICED CRACK IN THE WING SKIN IN MOST AFT OTBD SECTION OF LT WING. MECHANIC ALSO OBSERVED 2 RIVETS SHEARED THAT ATTACH THE OTBD AILERON HINGE BRACKET ASSY (CESSNA P/N 5021002-12) WHICH ARE SAME RIVETS THAT ATTACH THE TIP TANK SUPPORT BRACKETS (CESSNA P/N'S 0822600-29 AND -30 TO THE WING. THE MOST OTBD WING RIB WAS ALSO CRACKED IN THE MOST AFT LOWER SECTION (CESSNA P/N 0822040-17). TIP TANK STINGER (MOST AFT POINT) HAS SOME SLIGHT DAMAGE AS THOUGH IT STRUCK A SOLID OBJECT. AMOUNT OF WEIGHT WITH A FULL TANK OF FUEL BOUNCING ON THE TIP OF THE WING COULD ALSO BE A CONTRIBUTING FACTOR.

DURING A 100-HOUR INSPECTION, MECHANIC HAD REMOVED THE NR 5 CYLINDER TO REPLACE A BROKEN STUD AND NOTICED CYLINDER HAD BEEN CHAFING. A CLOSER INSPECTION REVEALED THE CRANKCASE WAS CRACKED ON THE CYLINDER MOUNT PAD AROUND THE LOWER RIGHT STUD. ONE CRACK RAN INSIDE THE STUD AREA TOWARDS THE CYLINDER SKIRT, AND ANOTHER CRACK RAN OUT FROM THE SAME STUD IN THE DOWNWARD DIRECTION. SUBMITTER SUSPECTS THE BROKEN STUD CAUSED CYLINDER TO BECOME LOOSE CAUSING CHAFING AND, ULTIMATELY, CASE TO CRACK. SUBMITTER SUGGESTS MFG (TCM) BE REQUIRED TO STAMP ITS CASES TO BETTER ENABLE TOTAL TIME TRACTABILITY.

DURING A 100-HOUR INSPECTION, MECHANIC NOTICED UPPER RIGHT (MOST AFT) STUD WAS BROKEN ON THE NR 4 CYLINDER PAD. THE STUD WAS BROKEN FLUSH WITH CYLINDER BASE. SUBMITTER SUSPECTS TIME IN SERVICE IS THE MAIN CAUSE FOR BREAKAGE OF THIS STUD. THERE IS NO WAY TO DETERMINE THE TOTAL TIME OF THIS STUD, OR THE CRANKCASE DUE TO A REMOVABLE DATA PLATE. WHILE THE NEWER CRANKCASES INCORPORATE A 7TH STUD, THE OLDER CASES RELY ON THE EXISITNG STUDS TO RETAIN THE CYLINDERS AND SHOULD BE REPLACED AT EACH OVERHAUL. SUBMITTER SUGGESTS THE MANUFACTURER (TCM) BE REQUIRED TO STAMP ITS CASES TO BETTER ENABLE TOTAL TIME TRACTABILITY.

DURING COURSE OF NORMAL FLIGHT, PILOT NOTICED AIRSPEED WAS APPROXIMATELY 15(+) KNOTS SLOWER THAN NORMAL, AND WHEN LANDING GEAR EXTENDED, PILOT NOTICED LEFT GREEN LIGHT CAME ON FIRST. (IN NORMAL CONDITIONS, THE NOSE LIGHT COMES ON FIRST). THE AIRCRAFT WAS INSPECTED, AND LEFT GEAR TORQUE TUBE ASSY FOUND BROKEN IN A SPIRAL AROUND TUBE ASSY IN THE FORK BOLT AREA.