SENECA FLIGHT OPERATIONS

WHILE PERFORMING AN INSPECTION ON THE R/H CIRCUIT BREAKER PANEL THE WIRE TERMINALS WERE FOUND BROKEN ON TWO OF THE THREE 75A FEEDER CIRCUIT BREAKERS AND THE THIRD TERMINAL WAS CRACKED AND ABOUT READY TO BREAK. THESE WIRES FEED POWER TO THE R/H CIRCUIT BREAKER PANEL FROM THE AFT POWER JUNCTION BOX. HAD THE LAST TERMINAL BROKEN ALL POWER FROM THE AFT POWER JUNCTION BOX TO THAT BREAKER PANEL WOULD HAVE BEEN LOST AND THE PANEL WOULD BE THEN BE FED SOLELY FROM THE 35A CROSS-FEED BREAKER WITH NO INDICATION TO THE FLIGHT CREW. THE CAUSE OF THE BREAKAGE WAS DUE TO THE WIRE RUNS BEING TOO SHORT CAUSING A STRAIN ON THE WIRES AND TERMINALS. A GENERAL VISUAL INSPECTION IS NOT SUFFICIENT TO LOCATE THIS ISSUE AS EACH WIRE ALSO HAS AN INSULATING BOOT ON EACH WIRE COVERING THE TRERMINAL GIVING A VISUAL EFFECT THAT THE WIRING IS INTACT. SLACK WAS OBTAINED FROM THE WIRE BUNDLE DOWNSTREAM FROM THE BREAKER PANEL AND THE WIRE TERMINALS WERE REPLACED AND REATTACHED TO THE CIRCUIT BREAKERS. OPPOSITE PANEL WAS INSPECTED WITH NO ISSUES FOUND.

UPON DECENT THE LT PITOT HEAT ANNUNCIATOR ILLUMINATED. THE AIRCRAFT MADE AN UNEVENTFUL LANDING AT DESTINATION. THE HEAT WAS DEFERRED PER MEL BUT DUE TO RESTRICTIONS OF THE MEL THE AIRCRAFT COULD NOT COMPLETE THE REMAINDER OF THE SCHEDULED MISSION AND RETURNED TO BASE. THE AIRCRAFT WAS THEN TURNED OVER TO MAINTENANCE. INVESTIGATION REVEALED THAT THE LT PITOT TUBE WAS DEFECTIVE AND SUBSEQUENTLY REPLACED AND AIRCRAFT RETURNED TO SERVICE AFTER SUCCESSFUL OPERATIONAL AND LEAK CHECKS.

UPON REACHING CRUISE ALTITUDE THE LEFT OIL PRESSURE GAUGE BEGAN TO FLUCTUATE WILDLY FROM ZERO UP TO MAXIMUM PSI. NO LOW OIL PRESSURE ANNUNCIATOR WAS OBSERVED AND ALL OTHER ENGINE PARAMETERS WERE NORMAL. THE AIRCRAFT RETURNED TO HOME BASE WHERE AN UNEVENTFUL LANDING WAS MADE. INVESTIGATION REVEALED A FAULTY OIL PRESSURE TRANSDUCER. THE TRANSDUCER WAS REPLACED AND GROUND OPERATIONAL CHECKS AT ALL POWER SETTINGS WERE SATISFACTORY. THE AIRCRAFT WAS RETURNED TO SERVICE.

UPON APPROACH TO LAND AT DESTINATION AIRPORT THE LT GENERATOR ANNUNCIATOR ILLUMINATED AND THE CREW NOTED THE LT GENERATOR VOLTAGE WAS ZERO. FOLLOWING PROCEDURES THE AIRCRAFT MADE AN UNEVENTFUL LANDING WHERE IT TAXIED TO THE RAMP AND MAINTENANCE WAS CALLED. INVESTIGATION REVEALED FAILURE OF THE LT STARTER/GENERATOR. NO GCU FAULTS WERE NOTED. AN OVERHAULED STARTER/GENERATOR WAS PROCURED AND INSTALLED, A SUCCESSFUL GROUND OPERATIONAL CHECK WAS PERFORMED AND THE AIRCRAFT WAS RETURNED TO SERVICE. IT IS UN-KNOW WHAT CAUSED THE FAILURE OF THE GENERATOR. A VISUAL INSPECTION OF THE BRUSH & BRUSH BLOCK AREA AND NOTHING DEFINITIVE WAS NOTED.

AFTER LANDING THE AIRCRAFT WAS TAXIED TO THE RAMP AND SHUT DOWN. WHEN THE CABIN DOOR WAS OPENED STRONG WIND CAUGHT AND FLUNG IT OPEN HARD RESULTING IN THE LOWER DOOR HINGE BEING BROKEN. THE AIRCRAFT WAS TURNED OVER TO MAINTENANCE WHERE SOME MINOR MODIFICATION WAS MADE IN PREPARATION FOR A FERRY FLIGHT BACK TO HOME BASE WHICH WAS MADE SUCCESSFULLY. A NEW HINGE WAS PROCURED AND INSTALLED. ALL CREW TO BE REMINDED OF SUCH INCIDENTS THAT CAN BE AVOIDED BY BEING AWARE OF OUTSIDE GROUND CONDITIONS AND PROPERLY POSITIONING OF AIRCRAFT ACCORDINGLY.

DURING LANDING, THE LT ENGINE OIL PRESSURE ANNUNCIATOR ILLUMINATED AND CREW NOTED THE OIL PRESSURE WAS AT 23PSI, THE ENGINE WAS SHUT DOWN AND THE AIRCRAFT WAS GROUNDED AND TURNED OVER TO MAINTENANCE FOR TROUBLESHOOTING. CREW ALSO NOTED THE OIL FILTER BYPASS INDICATOR WAS EXTENDED AFTER A POST SHUTDOWN CHECK. THE LT ENGINE OIL FILTER AND AN OIL SAMPLE WERE SENT FOR SPECTROGRAPHIC OIL ANALYSIS, THIS ENGINE HAD 8.3HRS SINCE THE PREVIOUS SOAP SAMPLE AND WAS ON A 25HR RE-SAMPLE FOR CONTAMINATION. RESULTS OF ANALYSIS INDICATED A FAULTY OIL PUMP. AN OVERHAULED PUMP WAS ACQUIRED AND INSTALLED AND THE AIRCRAFT WAS RETURNED TO SERVICE. A RE-SAMPLE OF THE OIL & FILTER IS TO BE PERFORMED IN 25HRS PER ENGINEERING.

AFTER LANDING AT DESTINATION AIRPORT AND AFTER SUBSEQUENT ENGINE SHUT DOWN THE CREW COULD NOT OPEN THE CABIN DOOR. INITIALLY ICE WAS SUSPECTED AS THE CAUSE BUT AFTER THAWING THE DOOR STILL COULD NOT BE OPENED. MAINTENANCE WAS CALLED AND IT WAS DETERMINED THAT AT LEAST ONE DOOR PIN WAS NOT RETRACTING FROM THE DOOR FRAME. CREW AND PASSENGERS DEPARTED FROM THE EMERGENCY EXIT. A SPECIAL FLIGHT PERMIT WAS ACQUIRED AND THE AIRCRAFT WAS FLOWN BACK TO HOME BASE (PEO) WHERE AN UNEVENTFUL LANDING WAS MADE. ON INITIAL INSPECTION IT WAS FOUND THAT ALL DOOR PINS ON THE AFT SIDE WOULD NOT FULLY RETRACT. THE DOOR STEPS, & TRIM WERE REMOVED AND EVENTUALLY THE CAUSE WAS FOUND TO BE DEBRIS AT THE SECOND FROM THE BOTTOM AFT DOOR PIN, WHICH WAS JAMMED BETWEEN RECEPTACLE BLOCK AND THE HOLE IN THE FRAME WHICH ALLOWS THE PIN TO FULLY RETRACT. THE DEBRIS, AFTER RETRIEVAL FROM DOOR FRAME WAS FOUND TO BE AN AN960-4L WASHER. THE WASHER WAS BEND/FOLDED OVER BUT IT CANNOT BE DETERMINED IF THE BEND WAS FROM THE JAMMING IN THE RECEPTACLE OR NOT. IT IS BELIEVED THE WASHER HAD BEEN THERE FOR SOME TIME, EITHER FROM PREVIOUS MAINTENANCE OR FROM THE FACTORY, AND EVENTUALLY FOUND ITS WAY TO THE AREA THAT ALLOWED IT TO JAM THE DOOR PIN. THE ENTIRE DOOR, DOOR STRUCTURE, LATCHING SYSTEM & ALL ATTACHMENT HARDWARE WERE INSPECTED. ALL LOOKED OK AND NO FURTHER DEBRIS COULD BE FOUND ANYWHERE IN THE DOOR STRUCTURE OR AROUND THE LATCHING MECHANISMS.THE AIRCRAFT WAS RETURNED TO SERVICE.

APPROXIMATELY 1 HOUR INTO FLIGHT BOTH LT ITT INDICATORS AGAIN BEGAN TO FLUCTUATE WITH NO ENGINE COMPUTER ANNUNCIATION. THE AIRCRAFT CONTINUED ON TO SCHEDULED DESTINATION WHERE AN UNEVENTFUL LANDING WAS MADE. THIS WAS 4 LANDINGS AND APPROXIMATELY 6 HOURS SINCE THE PREVIOUS ITT ISSUE WHERE THE INDICATOR WAS REPLACED. TROUBLESHOOTING REVEALED A GROUND WIRE HAD BECOME DETACHED FROM THE WIRE SHIELDING AT THE ITT CONNECTOR IN THE L/H ENGINE PYLON. THE CONNECTOR WAS INSPECTED AND CLEANED AND THE GROUND WIRE REATTACHED. GROUND OPERATIONAL CHECK OF THE ITT SYSTEM WAS OK. THE AIRCRAFT HAS SINCE FLOWN 13 HOURS WITHOUT THIS FAILURE. IT IS BELIEVED THE LOSS OF SHIELDING GROUND ALLOWED ELECTROMAGNETIC OR STATIC INTERFERENCE TO BE INDUCED INTO THE WIRE HARNESS AFFECTING THE SIGNAL GOING TO THE INDICATOR.

APPROXIMATELY 10 MINUTES INTO FLIGHT BOTH LT ITT INDICATORS BEGAN TO FLUCTUATE APPROXIMATELY 200 DEGREES. NO ENGINE COMPUTER ANNUNCIATION WAS NOTED. THE AIRCRAFT RETURNED TO HOME BASE WHERE AN UNEVENTFUL LANDING WAS MADE. THE ITT INDICATOR WAS REPLACED AND GROUND OPERATION AT MULTIPLE SUSTAINED POWER SETTINGS WAS PERFORMED WITH NO FAULTS AND THE AIRCRAFT WAS RETURNED TO SERVICE.

UPON ENGINE START THE RT ITT INDICATOR SHOWED NO INDICATION ON THE TAPE OR DIGITAL INDICATORS. NO ENGINE COMPUTER FAULTS WERE INDICATED. MEL ALLOWS FOR THE TAPE OR THE DIGITAL TO BE INOPERATIVE BUT NOT BOTH. A SPECIAL FLIGHT PERMIT WAS ACQUIRED AND THE ACFT WAS FLOWN BACK TO HOME BASE WITHOUT INCIDENT. A REPLACEMENT INDICATOR WAS ACQUIRED AND INSTALLED WHICH CORRECTED THE PROBLEM. IT IS BELIEVED THAT A DEFECT WAS CREATED DURING THE O/H PROCESS WHICH CAUSED THIS ISSUE.

WHILE AT CRUISE FLIGHT, THE RT ENGINE CHIP DETECTOR ANNUNCIATOR ILLUMINATED, ALL OTHER ENGINE PARAMETERS WERE NORMAL. AFM PROCEDURES WERE FOLLOWED AND A PRECAUTIONARY AND SAFE LANDING WAS MADE. THE ENGINES WERE SHUTDOWN AND THE ACFT TURNED OVER TO MAINTENANCE. AFTER FINDING NO METAL DEBRIS ON THE DETECTOR, IN THE FILTER OR TRANSFER GEARBOX AND THE ANNUNCIATOR EXTINGUISHED A TEST RUN OF THE ENGINE WAS MADE AND AFTER 5 MINUTES THE ANNUNCIATOR AGAIN ILLUMINATED. THE CAUSE OF THE ILLUMINATION WAS DETERMINED TO BE A FAULTY MAGNETIC CHIP DETECTOR. A NEW PART WAS PROCURED, INSTALLED AND THE ACFT RETURNED TO SERVICE AFTER A SUCCESSFUL TEST RUN OF THE ENGINE.

AT CRUISE FLIGHT MULTIPLE AMBER ANNUNCIATIONS ILLUMINATED, AOA PROBE, FLAP SPEEDBRAKE AND STALL WARNING, OFF FLAGS ALSO CAME INTO VIEW ON THE AOA INDICATOR AND BOTH FAST/SLOW INDICATORS. CREW FOLLOWED AFM PROCEDURES AND A SAFE LANDING WAS MADE AT DESTINATION AIRPORT. INVESTIGATION REVEALED THAT THE ANGLE OF ATTACK COMPUTER HAD FAILED. THE COMPUTER WAS REPLACED WITH AN O/H UNIT AND ALL SYSTEM CHECKS WERE NORMAL. TIME 13 YEARS AND 2936 HRS SINCE LAST INSTALLATION AND FATIGUE ARE SUSPECTED CAUSES OF FAILURE.

UPON TAKE OFF THE LT RUDDER PEDAL DEFLECTED FULL LT. THE RUDDER BIAS SYS WAS DEACTIVATED & THE RUDDER SYS RETURNED TO NORMAL. AFTER LANDING THE RUDDER BIAS SYS WAS TESTED & CHECKED OK, BUT RUDDER PEDAL WOULD STILL DEFLECT WHEN ENG POWER WAS APPLIED. IT WAS DETERMINED THAT MOISTURE DUE TO CONDENSATION HAD ENTERED THE VERTICAL LINE GOING TO THE BIAS CYLINDER WHICH IS NOT HEATED & FROZE EITHER DURING FLIGHT OR AFTER LANDING BLOCKING PRESS TO ONE SIDE OF THE BIAS SYS. THE WATER WAS EXTRACTED & SYSTEM OPERATES NORMALLY. PRIOR TO FLIGHT IN FREEZING TEMPS THAT THE SYS BE FLUSHED BY THE FLIGHT CREW ON FIRST FLIGHT OF THE DAY BY OPERATING ONLY ONE ENG TO POWER FOR SEVERAL SECONDS WITH THE RUDDER BIAS SYS OFF.

UPON DECENT FROM CRUISE A SHUDDER WAS DETECTED WHEN THE POWER LEVERS WERE RETARDED. FLIGHT CREW WAS ABLE TO DETERMINE IT WAS THE RT ENG CAUSING THE SHUDDER. ALL ENG PARAMETERS WERE NORMAL, AS SAFE LANDING WAS MADE. INVESTIGATION RESULTED IN THE DISCOVERY OF THE AFT ACCESSORY GEAR BOX BOLTS MISSING NUTS & WASHERS & THE INBD BOLT HAD SLID ALMOST ALL THE WAY OUT. NEW NUTS & WASHERS WERE INSTALLED & PROPERLY TORQUED. A SATISFACTORY FLIGHT TEST WAS THEN COMPLETED. THE ENG HAD RECENTLY BEEN DISASSEMBLED FOR A LIGHTNING INSPECTION BY THE MFG, IT IS BELIEVED THAT THE INSTALLATION OF THESE TWO NUTS WERE NEGLECTED AT THAT TIME.

UPON ENG START UP FOR DEPARTURE, PILOT NOTED LT DIGITAL TURBINE INDICATOR SHOWED NO DIGITS. ENG STARTED NORMALLY & ALL OTHER INSTRUMENTS READ NORMAL & THERE WERE NO ENG COMPUTER FAULTS. A SPECIAL FLIGHT PERMIT WAS ISSUED & ACFT WAS FLOWN TO HOME BASE WHERE IT WAS DETERMINED THAT THE INDICATOR WAS FAULTY. AN OVERHAULED INDICATOR WAS INSTALLED & THE ACFT RETURNED TO SERVICE. THE FAILED INDICATOR HAD 1.1 HRS SINCE OVERHAUL & A RECORDS CHECK SHOWED IT HAD BEEN REPAIRED FOR THE SAME DISCREPANCY.

DURING CLIMB OUT THE RT GEN ANNUNCIATOR ILLUMINATED & NO OUTPUT WAS OBSERVED ON THE AMMETER. CHECKLIST PROCEDURES WERE FOLLOWED & THE ACFT MADE AN UNEVENTFUL LANDING BACK AT DEPARTURE AIRPORT & THE ACFT WAS TURNED OVER TO MX. INITIAL INVESTIGATION NOTED THAT THE BITE INDICATOR ON THE RT GCU WAS INDICATING A GND FAULT & AN ABNORMAL AMOUNT OF STAINING WAS NOTED COMING FROM THE GEN EXHAUST ON THE RT ENG COWL. INSPECTION OF THE STARTER & GEN WHILE STILL INSTALLED REVEALED PITTING & SCORING ON THE COMMUTER. AFTER REMOVAL OF THE STARTER & GEN IT WAS DISCOVERED THAT THE FWD BEARING HAD FAILED WITH THE ABNORMAL PLAY ALLOWING THE COOLING FAN TO STRIKE THE HOUSING & THE RESULTANT DEBRIS GETTING INTO THE BRUSH & COMMUTER AREA, SHORTING, THUS CAUSING THE GND FAULT. THE STARTER & GEN WAS REPLACED WITH AN OVERHAULED UNIT & THE GCU WAS RESET. GND OPERATIONAL & PARALLELING CHECKS WERE GOOD. THE FAILED UNIT HAD 364 HOURS TO GO UNTIL REQUIRED OVERHAUL, 1,000HR INTERVAL.

FLIGHT DIRECTOR SYS NOTED INOPERATIVE DURING TAXI FOR TAKEOFF. AVIONICS WERE SHUTDOWN & TURNED BACK ON WHICH DID NOT CORRECT THE PROBLEM. AVIONICS HAD BEEN ON FOR CLOSE TO AN HOUR PRIOR TO TAXI. AVIONIC BAY DOORS WERE OPENED TO COOL SUSPECTED OVERHEATED UNITS WHICH DID CORRECT THE PROBLEM. ACFT FLEW TO TWO DESTINATIONS WITH NO ISSUES. AFTER ACFT RETURNED TO HOME BASE AVIONICS WERE DETERMINED TO BE OPERATING NORMALLY. FLIGHT GUIDANCE COMPUTERS, AVIONICS J BOXES & SYMBOL GENERATORS WERE REMOVED, PINS CLEANED & RE-INSTALLED. SATISFACTORILY OPERATED AVIONICS FOR OVER 1 HOUR. IT IS BELIEVED HEAT, ALONG WITH RESIDUE ON PINS CREATED THIS INCIDENT. CREWS ARE REQUESTED NOT TO OPERATE AVIONICS UNNECESSARILY ON THE GND FOR PROLONGED PERIODS.

APPROXIMATELY AFTER 1 HOUR INTO FLIGHT THE RT WINDSHIELD CRACKED. FLIGHT MANUAL PROCEDURES FOR THIS TYPE OF OCCURRENCE WERE FOLLOWED & AN UNEVENTFUL LANDING WAS MADE. AFTER LANDING INSPECTED THE WINDSHIELD & DETERMINED THE CRACKING HAD OCCURRED IN THE OUTER PANE ONLY. THE WINDSHIELD WAS SUBSEQUENTLY REPLACED WITH A FACTORY NEW WINDSHIELD & THE ACFT WAS RETURNED BACK TO SERVICE. THE CAUSE OF THE CRACKING IS TO BE DETERMINED BY THE INSURANCE COMPANY AS IT IS SUSPECTED A POSSIBLE EARLIER LIGHTNING STRIKE MAY HAVE BEEN A DETERMINING FACTOR IN THE FAILURE. IF LIGHTENING WAS NOT A FACTOR IT IS BELIEVED CRACKING MAY HAVE BEEN DUE TO A FAILURE OF THE HEATING ELEMENT AT THE LOWER BUSS BAR.

AFTER LANDING CREW NOTED RT ENG FIRE DETECT SYS FAILURE. ACFT WAS FERRIED BACK TO HOME BASE. INVESTIGATION REVEALED ENG FIRE DETECTOR LOOP CHAFFED THROUGH UNDER THE AFT ENG HEAT SHIELD, GREEN SHEETS AT INBD END. CAUSE WAS DUE TO IMPROPER ROUTING AT LAST ENG CHANGE. DETECTOR WAS REPLACED WITH NEW PART & ACFT RETURNED TO SERVICE.

UPON INITIATING START OF THE LT ENGINE, NOTHING HAPPENED. NONE OF THE LT ENGINE INSTRUMENTS HAD POWER AND THERE WERE SEVERAL OTHER SYSTEMS THAT WOULD NOT OPERATE AS WELL. INVESTIGATION REVEALED LT MAIN CURRENT LIMITER (FL1) HAD FAILED. NO OVERHEATING AT THE LIMITER WAS EVIDENT. CURRENT LIMITER WAS REPLACED. POWER UP INSPECTION WAS MADE AND A NORMAL START INITIATED WITH NO ANOMALIES DETECTED. THE AIRCRAFT WAS THEN RETURNED TO SERVICE AFTER A FULL, ENGINES RUNNING, SYSTEMS CHECK.

DURING CLIMB TO CRUISE ALTITUDE THE AIRCRAFT PRESSURIZATION SYSTEM DID NOT APPEAR TO BE MAINTAINING PRESSURIZATION PROPERLY AS THE AIRCRAFT CONTINUED TO CLIMB AS THE CABIN SEEMED TO RISE FURTHER AND BY 17,000FT A DECISION WAS MADE TO DESCEND AND RETURN TO HOME BASE WHERE AN UNEVENTFUL LANDING WAS MADE. DOOR SEAL/DOOR FRAME AREA REVEALED A POSSIBLE LEAK IN THE UPPER AFT CORNER. THE AREA OF THE SUSPECTED LEAK FELT SLIPPERY AND IS BELIEVED THAT A POOR SEAL WAS MADE DUE TO THIS, AND THE ADDED LUBRICATION FROM RAIN WATER THAT DAY. THE AREA WAS MILDLY SCUFFED AND BOTH THE DOOR FRAME AND SEAL WERE CLEANED. A GROUND CHECK WITH ENGINES RUNNING WAS SATISFACTORY.

DURING CRUISE FLIGHT THE NR 1 ITT INDICATOR WENT TO ZERO. THE AIRCRAFT RETURNED TO HOME BASE WHERE AN UNEVENTFUL LANDING WAS MADE, DURING RETURN FLIGHT THE INDICATOR BEGAN TO WORK BUT WAS LOWER THAN NORMAL AND ERRATIC. THE GAUGE WAS PARTIALLY REMOVED FROM THE PANEL AND THE PROBLEM COULD BE DUPLICATED BY TAPPING ON THE BACK OF THE GAUGE. THE GAUGE WAS REPLACED WITH AN OVERHAULED UNIT AND GROUND OPERATIONS CHECKS WERE NORMAL. THE AIRCRAFT WAS RETURNED TO SERVICE.

CREW WENT TO PERFORM A PREFLIGHT INSPECTION AND DISCOVERED THE BATTERY VOLTAGE WAS AT APPROXIMATELY 22.5 VOLTS AND THE BATTERY HOT LIGHT WAS ILLUMINATED. AFTER APPROXIMATELY 3.5 HRS THE BATTERY HAD COOLED TO A USEABLE TEMPERATURE. PRIOR TO THE NEXT FLIGHT, AS A PRECAUTION, THE BATTERY WAS REMOVED FOR INSPECTION AND A SERVICEABLE UNIT INSTALLED. THE REMOVED BATTERY WAS INSPECTED, DEEP CYCLED AND IS NOW APPROVED FOR RETURN TO SERVICE WITH NO DEFECTS NOTED. THE CAUSE OF THE OVERHEAT CONDITION IS BELIEVED TO BE THAT THE GPU PLUG WAS NOT FULLY INSERTED INTO THE AIRCRAFT ALLOWING FOR THE HIGH CURRENT DRAW OF THE AIR CONDITIONER TO BE DRAWN DIRECTLY FROM THE BATTERY. TO PREVENT A FUTURE OCCURRENCE, THE FLIGHT CREWS HAVE BEEN INSTRUCTED TO DISCONNECT THE SHIP’S BATTERY IF A GPU IS TO BE CONNECTED FOR ANYTHING OTHER THAN ENGINE START.

AFTER REACHING THIS ALTITUDE THE PILOT’S WINDOW CRACKED IN NUMEROUS PLACES. FOLLOWING FLIGHT MANUAL PROCEDURES, THE CREW SLOWED THE AIRCRAFT TO 230K AND DESCENDED TO AN ALTITUDE WHERE A CABIN DIFFERENTIAL PRESSURE OF 7.5 COULD BE MAINTAINED. THE CREW THEN DECIDED TO DIVERT TO NEAREST AIRPORT WHERE AN UNEVENTFUL LANDING WAS MADE. THERE WAS NO LOSS OF PRESSURIZATION, NO INDICATION OF ANY IMPACT, THE AIRCRAFT APPEARED TO BE OPERATING NORMALLY, AND THE WINDSHIELD HEAT WAS ON. IT WAS DECIDED TO REPLACE THE WINDSHIELD WHERE IT LANDED. THE WINDSHIELD WAS LAST REPLACED IN 1995 AND A SERVICEABLE WINDSHIELD WAS INSTALLED AT THAT TIME. IT IS BELIEVED THAT THE CAUSE OF THE CRACKS WERE DUE TO EROSION OF THE OUTER SURFACE ANTI-STATIC COATING, AND A STATIC BUILD UP ON THE OUTER SURFACE OF THE WINDOW WHICH FOUND A GROUND PATH THROUGH THE WINDOW VIA THE WINDSHIELD HEATING ELEMENTS.

ON ROLLOUT AFTER LANDING THE CREW HAD NO BRAKING. EMERGENCY BRAKES AND THRUST REVERSER WERE OPERATIONAL. THE AIRCRAFT SAFELY SLOWED AND TAXIED TO THE RAMP UTILIZING THRUST REVERSERS TO CONTROL AIRCRAFT SPEED, THEN CHOCKS WERE APPLIED. THE CREW DISCOVERED A SIGNIFICANT AMOUNT OF HYDRAULIC FLUID COMING FROM THE MID-FUSELAGE BELLY DRAINS. INVESTIGATION REVEALED A DAMAGED RT BRAKE LINE (ALUMINUM TUBING) AT APPROXIMATE FUSELAGE STATION NR 175.0 UNDERNEATH THE CABIN CENTER FLOOR, AND THE BRAKE RESERVOIR WAS DEPLETED. THE LINE WAS SLIGHTLY BENT/MISALIGNED ALLOWING THE LT ELEVATOR CABLE TO RUB ON IT, EVENTUALLY WEARING THROUGH THE TUBING WALL. THE TUBING WAS REPAIRED BY REPLACING THE DAMAGED SECTION OF TUBING. THE LINE WAS REPOSITIONED TO PREVENT FURTHER CHAFING AND THE RESERVOIR WAS SERVICED. AIR WAS BLED FROM THE SYSTEM AS NECESSARY AND THE BRAKE SYSTEM OPERATIONALLY AND LEAK CHECKED SATISFACTORY. FLUID WAS FLUSHED/CLEANED FROM THE BELLY OF THE FUSELAGE, AND THE AIRCRAFT WAS RETURNED TO SERVICE. AFTER INITIALLY LEARNING OF THE FLUID LEAK, AN INSPECTION OF THE DEPARTURE RAMP AREA REVEALED EVIDENCE OF THE LEAK PRIOR DEPARTURE. HOWEVER, IT WAS MINOR COMPARED TO AMOUNT OF FLUID NOTICED AFTER LANDING, THE CREW VERIFIED THAT THE RESERVOIR INDICATED FULL DURING THE PREFLIGHT, WHICH SUGGESTS THE LINE BEGINNING TO LEAK AT TIME OF DEPARTURE. IT IS BELIEVED THAT, DUE TO THE FACT THAT THE CREW HAD BRAKING PRIOR TO TAKEOFF, TOTAL FAILURE OF THE LINE MOST LIKELY OCCURRED EITHER DURING TAXI FOR TAKEOFF, OR AFTER TAKEOFF, WITH TOTAL RESERVOIR DRAINAGE OCCURRING IN FLIGHT. THE RESERVOIR IS PRESSURIZED WITH CABIN PRESSURIZED AIR WHEN IN FLIGHT WHICH WOULD ACCELERATE THE LEAK. THIS AREA OF THE AIRCRAFT ONLY GETS INSPECTED DURING A PHASE 5 INSPECTION WHICH IS EVERY 1200 HRS OR 36 MONTHS, WHICHEVER OCCURS FIRST. SUGGEST MAINTENANCE SHOPS/PERSONNEL PERFORM MORE DETAILED INSPECTION OF AREAS AFTER INSPECTION/MAINTENANCE, PRIOR TO REINSTALLING PANELS.

JUST PRIOR TO DESCENT TO SCHEDULED AIRPORT, THE LT ENGINE COMPUTER ANNUNCIATOR ILLUMINATED. FOLLOWING AFM PROCEDURES THE COMPUTER WAS RESET AND THE LIGHT WOULD NOT REMAIN EXTINGUISHED. ALL OTHER ENGINE INDICATIONS WERE NORMAL. A SAFE LANDING WAS MADE. THE PILOT WAS DIRECTED TO RETRIEVE FAULT CODES MANUALLY FROM THE ENGINE COMPUTER WHICH REVEALED A FAULT IN THE FUEL CONTROL UNIT (FCU) POWER LEVER ANGLE TRANSMITTER. MAINTENANCE WAS ARRANGED FROM A NEARBY AIRPORT TO ARRIVE THE FOLLOWING DAY TO LOOK INTO THE ISSUE. AFTER ANALYZING THE NR 1 DIGITAL ELECTRONIC ENGINE COMPUTER (DEEC) LIVE DATA, IT COULD NOT BE DETERMINED THAT THERE WERE ANY FAULTS. NO FAULT CODES WERE RECORDED BY REQUESTING FLT ON THE HTT INTERFACE, BUT THE MEMORY WAS FULL AND REQUIRED DOWNLOAD. THE ENGINE WAS STARTED AND RAN FOR A LENGTH OF TIME WITH THE COMPUTER BEING MONITORED AND NO FAULTS WERE SHOWN AND THE INITIAL FAULT COULD NOT BE DUPLICATED. AN INSPECTION WAS MADE OF THE WIRE HARNESS AND NO DEFECTS WERE FOUND. THE AIRCRAFT WAS RETURNED TO SERVICE AND THE DOWNLOADED DATA SENT TO JET CARE TO BE ANALYZED. AFTER THE AIRCRAFT ARRIVED BACK AT HOME BASE, THE DOWNLOAD FROM THE DEEC WAS RECEIVED AND VIEWED BY THE DIRECTOR OF MAINTENANCE. AFTER A REVIEW OF THE DOWNLOAD IT WAS DISCOVERED THAT THE WERE STORED IN THE FAULT HISTORY. A CURRENT DOWNLOAD OF THE DEEC WAS MADE AND SHOWED NO FAULTS ON THE TRIP TO HOME BASE. THE AIRCRAFT WAS SCHEDULED AND FLOWN TO A MAINTENANCE FACILITY, WITHOUT INCIDENT, FOR FURTHER REVIEW. A MORE DETAILED INSPECTION OF THE HARNESS REVEALED NO FAULTS AND IT WAS DECIDED TO REPLACE THE FUEL CONTROL UNIT AS IT IS THE MOST LIKELY UNIT TO CAUSE THIS TYPE OF FAILURE. THE AIRCRAFT HAS BEEN RETURNED TO SERVICE. TO DATE WE HAVE NO EXPLANATION AS TO WHY THIS FAULT OCCURRED OR WHY IT COULD NOT BE VIEWED ON THE DEEC HTT LIVE DATA. IN THE FUTURE, THE DOWNLOADED DATA WILL BE REVIEWED PRIOR TO RETURNING THE AIRCRAFT TO SERVICE.

AFTER DEPARTURE FROM AIRPORT THE RT ENGINE COMPUTER ANNUNCIATOR ILLUMINATED. FOLLOWING AFM PROCEDURES THE COMPUTER WAS RESET AND THE LIGHT EXTINGUISHED. A SHORT TIME LATER THE ANNUNCIATOR ILLUMINATED AGAIN AND WAS AGAIN RESET. ALL OTHER ENGINE INDICATIONS WERE NORMAL. IT WAS DECIDED TO DIVERT AIRPORT WHERE MAINTENANCE FACILITY WAS AVAILABLE AND HAVE THE ANNUNCIATION INVESTIGATED. ON THE FLIGHT TO THE AIRPORT THE ANNUNCIATOR REMAINED EXTINGUISHED. AFTER ANALYZING FAULT CODES OF NR 2 DIGITAL ELECTRONIC ENGINE COMPUTER (DEEC), IT WAS DISCOVERED THERE WAS A FAULT IN THE N2 MONOPOLE (SPEED SENSOR). THE N2 MONOPOLE ON THE NR 2 ENGINE WAS REPLACED, AN ENGINE RUN PERFORMED, AND THE AIRCRAFT RETURNED TO SERVICE. DATA FROM THE DOWNLOAD OF THE DEEC SHOWED NO OTHER FAULTS. WHILE THIS FAILURE IS SOMEWHAT RARE, IT IS ALSO NOT UNCOMMON AND USUALLY FAILS ON THE COMPUTER CIRCUIT SIDE OF THE MONOPOLE WHICH ALLOWS FOR PILOT TO HAVE NORMAL INDICATION OF ENGINE SPEED ON THE N2 INDICATOR IN THE COCKPIT WHICH ALLOWS PILOT TO VERIFY PROPER ENGINE FUNCTION. NO INFORMATION ON THE CAUSE OF THESE FAILURES BUT WOULD SUSPECT FATIGUE FROM VIBRATION AS THIS SENSOR IS MOUNTED ON THE ACCESSORY GEARBOX.

THE AIRCRAFT TOOK OFF AND MADE A NORMAL CLIMB TO CRUISE ALTITUDE. AFTER A FEW MINUTES IT WAS NOTED THAT THE LANDING GEAR UNLOCK AND HYD PRESS ON ANNUNCIATORS ILLUMINATED, A THUMP/BUMP WAS HEARD AND FELT, AFTER WHICH THE ANNUNCIATORS EXTINGUISHED. THIS HAPPENED INTERMITTENTLY SEVERAL TIMES. THE CREW FELT THAT IT WAS THE NOSE GEAR UNLOCKING (AND SUBSEQUENTLY RETRACTING INTO THE WELL) HOWEVER THIS COULD NOT BE CONFIRMED BY THE CREW. THE AIRCRAFT THEN DIVERTED AN ALTERNATE AIRPORT FOR A PRECAUTIONARY LANDING. THE GEAR EXTENDED NORMALLY AND A SAFE LANDING WAS MADE. THE AIRCRAFT WAS FERRIED TO HOME BASE WITH THE GEAR DOWN AND LOCKED. AN UNEVENTFUL LANDING WAS MADE. INITIAL INVESTIGATION DID NOT REVEAL ANY POSITIVE RESULTS. AFTER JACKING THE AIRCRAFT THE GEAR WAS CYCLED AND THE PROBLEM COULD NOT BE DUPLICATED. IT WAS NOTED THAT THE NOSE GEAR SPADE DOOR APPEARED TO BE DRAWING UP TIGHTER THAT THE OTHER DOORS. IT WAS ALSO NOTED THAT THERE WAS ALSO A SMALL AMOUNT OF AN UNKNOWN PASTY SUBSTANCE ON THE NOSE GEAR UPLOCK HOOK. THE MAIN LANDING GEAR SHOWED NO DEFECTS EITHER VISUALLY OR DURING EXTENSION/RETRACTION. THE GEAR HAD RECENTLY (PRIOR TO THIS TRIP) BEEN CYCLED DUE TO A RT BRAKE CHANGE TO ENSURE BRAKE HOSE CLEARANCE, NO DEFECTS WERE NOTED AT THAT TIME. THE NOSE GEAR SPADE DOOR WAS ADJUSTED AND THE DEBRIS REMOVED FROM THE UPLOCK HOOK. AS A PRECAUTION THE UPLOCK ROLLERS AND DOOR HINGES WERE LUBED AND A RELEASE AGENT APPLIED TO THE SPADE DOOR FLANGES. THE GEAR WAS CYCLED NUMEROUS (20-25) TIMES, INCLUDING SLOW CYCLE AND TIMED CYCLE CHECKS. ALL CHECKS SATISFACTORY PER CESSNA MODEL 550 MAINTENANCE MANUAL. IT IS SURMISED THAT THE COMBINATION OF THE SNUG SPADE DOOR, COMBINED WITH THE DEBRIS ON THE UPLOCK HOOK, POSSIBLE MOISTURE ON THE SPADE DOOR FLANGES (POSSIBLY PICKED UP UPON LANDING/TAKE OFF AT PREVIOUS AIRPORT) AND THE FREEZING TEMPERATURES AT THAT TIME, ALL CONTRIBUTED TO THE NOSE GEAR NOT FULLY ENGAGING THE UPLOCK HOOK.

DURING POST ENGINE START/PREFLIGHT CHECKS, NOTED THE "SPEED BRAKE EXTENDED" ANNUNCIATOR FAILED TO ILLUMINATE. VISUAL INSPECTION CONFIRMED THE BRAKES EXTENDED, & "HYD PRESS" LIGHT EXTINGUISHED CONFIRMING SYS HAD COMPLETED IT’S CYCLE. ANNUNCIATOR LIGHT TEST PERFORMED & LIGHT FUNCTIONED NORMALLY. SPEED BRAKES CYCLED AGAIN WITH NO CHANGE. ENGINES SHUTDOWN. INVESTIGATION REVEALED A WIRE BUNDLE CHAFING ON SECONDARY WING STRUCTURE INSIDE RT AFT WING APPROX WS 24. CHAFE WORN THROUGH PROTECTIVE SHIELDING & THROUGH WIRE INSULATION. SUBSEQUENT ARC MELTED & OPENED WIRE. CIRCUIT BREAKER NOT POPPED & NO REPORTS OF BREAKER BEING POPPED BY PREVIOUS CREW. CIRCUIT BREAKER INSPECTED, NO DEFECTS NOTED & OPERATED NORMALLY WHEN MANUALLY PULLED. WIRE REPAIRED USING A MANUAL SPLICE. BUNDLE REWRAPPED & POSITIONED TO PREVENT FURTHER CHAFING. NO DAMAGE TO STRUCTURE NOTED. A GROUND OPS CHECK OF SYS PERFORMED NORMALLY & ACFT RETURNED TO SERVICE.

AFTER TAKEOFF CREW WENT TO SELECT GEAR UP & NOTICED THAT THE GEAR DOWNLOCK LIGHTS WERE INOPERATIVE. CREW CYCLED GEAR WITH NO AFFECT AND NOTED THE GEAR UNLOCK LIGHT ILLUMINATED AND EXTINGUISHED AS THOUGH A NORMAL CYCLE HAD BEEN COMPLETED. GEAR ALSO FELT NORMAL DURING THE RETRACT/EXTEND CYCLE. CREW PERFORMED A LIGHT TEST AND LIGHTS STILL WOULD NOT ILLUMINATE. AFTER A FLY BY CONFIRMING GEAR APPEARED TO BE FULLY DOWN, AND A REVIEW OF THE GEAR SCHEMATIC DIAGRAMS, IT WAS DETERMINED THAT ONLY AN INDICATION FAULT WAS OCCURRING AND A SAFE LANDING COULD BE MADE. THE EMERGENCY GEAR SYSTEM WAS ACTUATED AND A SAFE LANDING WAS MADE AT DEPARTURE AIRPORT. TROUBLESHOOTING REVEALED A FAULT IN THE LIGHT DIMMING CIRCUITRY (COMMON TO ALL THREE LIGHTS) AND A FAULTY SOLDER JOINT WAS FOUND AND REPAIRED ON THE CONTROL PRINTED CIRCUIT BOARD (PCB101). EMERGENCY SYSTEM WAS RESET AND SEVERAL NORMAL GEAR CYCLES MADE. AIRCRAFT WAS RETURNED TO SERVICE.

ON LANDING, ENCOUNTERED SEVERE CROSSWIND GUSTS CAUSING ACFT TO YAW ON TOUCHDOWN. AFTER A SUCCESSFUL LANDING, NOTED A SEVERE SWAYING OF THE NLG & VIBRATION FELT IN RUDDER PEDALS. ACFT STOPPED & DISCOVERED THE NLG TIRE BLOWN & RIMS BROKEN OFF. AT THE HANGER NOTED A SMALL DENT/SCRATCH ON EACH INBOARD HEATED LEADING EDGE. BOTH ENGINES WERE INSPECTED. RT ENGINE FOUND TO HAVE DAMAGE TO ROUGHLY HALF OF THE FAN BLADES FROM PIECES OF WHEEL RIM ENTERED. LT ENGINE NO DAMAGE. RT ENGINE DAMAGE LIMITED TO FAN BLADES, FAN SHROUD, FAN STATOR, AND ITT SENSOR. NO DAMAGE FOUND IN THE CORE. SOME SHEET METAL DAMAGE NOTED ON AFT EDGE OF INLET. FURTHER INSPECTION MADE ON REMAINDER OF ACFT & MINOR DAMAGE NOTED ON BOTH HEATED LEADING EDGES, A MINOR DENT WAS DISCOVERED UNDER THE FUSELAGE JUST AFT, AND TO LT OF NLG WW. LT LANDING LIGHT LENS CRACKED FROM IMPACT, & MINOR CHIP NOTED ON UNDERSIDE OF RT FLAP. THE WHEEL/TIRE ASSY REPLACED. DAMAGED FAN BLADES & ITT SENSOR ARE TO BE REPLACED AND THE FAN SHROUD & STATOR WILL BE REPAIRED AS NECESSARY. THE NDT INSPECTION ON THE REMOVED WHEEL WAS DUE AT THE NEXT TIRE CHANGE. A VISUAL INSPECTION AT THE PREVIOUS TIRE CHANGE SHOWED NO DEFECTS. WHEEL HAD 92 LANDINGS SINCE PREVIOUS TIRE CHANGE. IT IS BELIEVED THE CAUSE OF THE FAILURE IS DUE TO EXCESSIVE SIDE LOADING ON THE NOSE WHEEL DUE TO UNEXPECTED AND SEVERE WIND SHEAR UPON LANDING.

UPON APPROACH TO DESTINATION AIRPORT THE GEAR WAS SELECTED DOWN. THE PILOT NOTED THAT THE LT GEAR DOWN & LOCKED ANNUNCIATOR WAS NOT ILLUMINATED. THE PILOT RECYCLED THE GEAR BUT THE LIGHT STILL WOULD NOT ILLUMINATE. FOLLOWING PROCEDURES, THE EMERGENCY GEAR EXTENSION SYSTEM WAS ENGAGED AND A SAFE LANDING WAS MADE. AFTER TAXI TO THE RAMP, IT WAS NOTED THAT THE DOWN AND LOCKED ANNUNCIATOR HAD ILLUMINATED. A FERRY PERMIT WAS OBTAINED AND THE AIRCRAFT WAS FLOWN TO HOME BASE GEAR DOWN, WHERE AN UNEVENTFUL LANDING WAS MADE. INVESTIGATION INTO THE PROBLEM REVEALED THAT THE LT GEAR DOWNLOCK SWITCH HAD FAILED. THE SWITCH WAS REPLACED, THE EMERGENCY GEAR SYSTEM WAS RESET, AND THE GEAR WAS CYCLED NUMEROUS TIMES WITHOUT ANY PROBLEMS. THE AIRCRAFT WAS RETURNED TO SERVICE.

AFTER STARTING RT ENGINE THE START BUTTON LIGHT COULD NOT BE EXTINGUISHED. AFTER SHUTDOWN THE RT ENGINE REMAINED SPOOLING AS THE STARTER WAS STILL ENGAGED AND THE BATTERY HAD TO BE DISCONNECTED TO TERMINATE THE STARTER. THE RT START RELAY WAS REPLACED AND OPERATIONAL CHECK OF THE START SYSTEM WAS SATISFACTORY.

DURING SCHEDULED INSPECTION IT WAS DISCOVERED THAT THE LANDING GEAR RETRACT PUSH-PULL TUBE HAD BEEN STRIKING THE FUEL LINES IN THE RT GEAR WELL. DAMAGE TO THE PUSH-PULL TUBE WAS MINIMAL AND LIMITED TO THE PAINT BEING REMOVED, DAMAGE TO THE FUEL LINES WAS SUCH THAT APPROXIMATELY 40% OF THE LINE WALL THICKNESS HAD BEEN WORN AWAY. BOTH FUEL LINES WERE REPLACED. ONE OTHER AIRCRAFT HAD BEEN FOUND WITH THIS CONDITION IN PREVIOUS YEARS, AND ALTHOUGH THAT AIRCRAFT HAD MUCH HIGHER TOTAL TIME (11,000+ HRS.) THE RT WING HAD BEEN PREVIOUSLY REMOVED AND ON THAT AIRCRAFT THE LINES WORE TO THE POINT OF LEAKING.

AFTER LANDING, THE NR 2 HYDRAULIC LIGHT CAME ON AND THE NR 2 HYDRAULIC PRESSURE WENT TO -0- PSI. INVESTIGATION REVEALED THE NR 2 HYDRAULIC PUMP HAD FAILED. THE PUMP AND REQUIRED FILTERS WERE REPLACED AND THE AIRCRAFT WAS RETURNED TO SERVICE. THIS FAILED, OVERHAULED PUMP WAS A RECENT WARRANTY REPLACEMENT FOR PREVIOUS OVERHAULED PUMP THAT HAD FAILED WITH LOW (220 HRS) TSO. BOTH PUMPS WERE O/H BY SAME REPAIR STATION. THIS OPERATOR HAS NEVER SEEN THIS BRAND OF PUMP GO TO THE REQUIRED O/H INTERVAL (3,000 HRS). THESE PUMPS GENERALLY SEEM TO FAIL AROUND 700-900 HRS OFOPERATING TIME AS DERIVED FROM PREVIOUS AC RECORDS. (K)

INSP, A LOUD SCRAPING NOISE WAS HEARD WHEN FAN WAS TURNED. BORESCOPE OF TURBINE SEC., AFTER EXHAUST DUCT WAS REMOVED, NR 4 BRG HSG HEAT SHIELD WAS FOUND BROKEN, TWISTED, IN 3 SEPARATE PIECES, WAS RUBBING ON AFT FACE OF NR 3 LOW PRESSURE TURBINE DISC. DISC WAS GOUGED, HAD TO BE REPLACED ALONG WITH 10 BLADES. MINOR DAMAGE TO EXHAUST DUCT AT GAP BETWEEN DUCT, NR 3 LPT WHERE PIECES OF HEAT SHIELD HAD EXITED, A CRACK WAS NOTED ON 1 OF THE SUPPORT STRUTS. NR 4 BRG HAD PITTING ON ROLLERS, BUT COULD NOT BE CONFIRMED THAT IT WAS DUE TO LOSS OF HEAT SHIELD. ALL HEAT SHIELD MNTG HARDWARE WAS INTACT AND TIGHT. PART TT AND/OR UNRECOGNISED FATIGUE CRACK WERE CONTRIBUTING FACTORS TO THIS FAILURE.

WHILE PERFORMING A SCHEDULED INSPECTION, 3 OF THE 4 ENGINE MOUNT (CUSHION) BOLTS WERE FOUND LOOSE. 2 REQUIRED 1 FULL TURN TO TIGHTEN, AND THE 3RD TOOK ALMOST 2 TURNS TO TIGHTEN. THE SELF LOCKING FEATURE OF THE NUTS WAS CHECKED AND APPEARED TO BE OK. IT CAN ONLY BE ASSUMED THAT THE BOLTS WERE NOT PROPERLY TORQUED BY THE MFG AT ENGINE INSTALLATION. THE BOLTS WERE TORQUED IAW SRM AND THE OPPOSITE ENGINE MOUNT BOLTS WERE CHECKED AND FOUND TO BE PROPERLY TORQUED. (K)

DURING ANNUAL INSP, CRACKS WERE NOTED IN FWD CARRY-THRU SPAR WEB. LOCATED AT LT UPPER OB MOST HUCK BOLTS (2 EA) ON FWD SIDE OF CARRY-THRU ASSY. HEAD SIDE OF UPPER HUCK BOLT IS INACCESSIBLE FOR VIEWING WITHOUT WING REMOVAL. LWR HUCK BOLT IS ACCESSIBLE, NO MOVEMENT OR CRACKING WAS NOTED. WEB SKIN AROUND HUCK BOLTS WAS REMOVED DOWN TO WEB TIE PLATE. PLATE WAS EDDY CURRENT INSPECTED FOR CRACKS, NONE WERE DETECTED. THIS AREA WILL BE REINSPECTED BY DYE PENETRANT EVER ANNUAL INSP, AND BY EDDY CURRENT METHOD EVERY 500 HRS. THIS AC HAS 2 BOLT AREAS CRACKED ON ONE SIDE, REQUIRED REPAIR DOES NOT EXTEND INTO THIS AREA. THE HIGH AC TIME AND DAMAGE HISTORY WERE CONTRIBUTING FACTORS TO THE CRACKING IN THIS AREA.

AFTER TAKEOFF AND DURING CLIMBOUT, THE PILOT EXPERIENCED A COMPUTER GENERATED AUTOMATIC ROLL BACK OF POWER ON THE NR 1 ENGINE. THE NR 2 ENGINE WAS BROUGHT BACK TO A MATCHING POWER SETTING. IT WAS THEN NOTICED THAT THE NR 1 ENGINE ITT WAS MORE THAN 100 DEGREES HIGHER THAN THE NR 2 ENGINE. THE NR 1 ENGINE WAS SHUT DOWN AS A PRECAUTIONARY MEASURE, AND AN UNEVENTFUL LANDING WAS MADE. AFTER SEVERAL GROUND MAINTENANCE RUNS FOR TROUBLESHOOTING, IT WAS DETERMINED THAT SEVERE HOT SECTION DISTRESS HAD OCCURRED. THE ENGINE WAS REMOVED FOR REPAIR. CAUSE OF PROBLEM UNKNOWN.

PILOT REPORTED THE WING DEICE SYSTEM WAS INOPERATIVE. AFTER VERIFYING ELEC PORTION OF SYS WAS FUNCTIONING, A GROUND OPER CHK PERFORMED. DISCOVERED VERY LITTLE FLOW GETTING TO RT SLATS, LT SLATS APPEARED TO BE GETTING SUFFICIENT HEAT, BUT BOTH SIDES ARE REQUIRED TO OPER PROPERLY TO GET A PROPER INDICATION ON PANEL. AFTER VERIFYING NO LEAKS IN AIRFRAME DUCTING, DISCOVERED THE INTERIOR WALLS OF FLEX DUCTS ATTACHED TO SLATS WERE DEBONDED AND COLLAPSING. THIS EITHER RESTRICTED/BLOCKED FLOW OF HOT AIR TO SLATS. INSP OF LT FLEX DUCTS REVEALED SAME CONDITION EXISTED, FAILURE OF THAT SIDE WAS IMMINENT. DUCTS HAVE A 3,000 HR TBO AND WERE JUST REPLACED 66.6 HRS PRIOR. SUSPECT INCORRECT MFG PROCESS. (X)

THE PILOT REPORTED THERE WAS AN ABNORMAL 'THUMP' NOISE COMING FROM THE NOSE GEAR AREA WHEN THE GEAR WAS RETRACTED ON SEVERAL OCCASIONS. AN INVESTIGATION REVEALED THE CENTER RT NOSE LANDING GEAR DOOR BELLCRANK/HINGE WAS BROKEN IN HALF. AN INSPECTION OF THE ENTIRE NOSE GEAR AND WHEELWELL AREA SHOWED NO FURTHER DAMAGE. METAL FATIGUE IS THE SUSPECTED CAUSE OF THIS FAILURE. SUBMITTER SUGGESTED CLOSE INSPECTION OF THESE HINGES BE MADE ANY TIME LANDING GEAR WORK IS PERFORMED AS WELL AS DURING ALL PRE AND POST-FLIGHT INSPECTIONS.

DURING START OF THE RIGHT (NR 2) ENGINE, THE CREW NOTICED AN UNUSUAL NOISE THAT LASTED APPROXIMATELY 30 SECONDS. SCANNING THE INSTRUMENTATION REVEALED THE 'HYD 2' LIGHT ILLUMINATED AND THE HYDRAULIC PRESSURE GAUGE INDICATED ZERO. EXAMINATION OF THE RT ENGINE DRIVEN HYDRAULIC PUMP AFTER REMOVAL REVEALED THE DRIVESHAFT WAS INTACT, HOWEVER, IT ROTATED WITH LITTLE RESISTANCE INDICATING AN INTERNAL FAILURE. PUMP TBO IS 3,000 HOURS, HOWEVER, THIS INTERVAL IS RARELY ACHIEVED.

AFTER A NORMAL FLIGHT, HYDRAULIC FLUID WAS NOTICED RUNNING DOWN THE VERTICAL STABILIZER EMANATING FROM THE AFT ELEVATOR AREA. INVESTIGATION REVEALED THAT ONE OF THE FLEX HYDRAULIC HOSES FOR THE RUDDER/YAW SERVO WAS MAKING CONTACT WITH AND RUBBED THROUGH THE RIGID HYDRAULIC LINE (FOR THE SERVO) CAUSING THE LEAK. NO DAMAGE WAS EVIDENT TO THE FLEX HOSE. REPLACED THE LINE WITH A NEW ASSEMBLY. THIS AREA IS NOT READILY ACCESSIBLE AND THE DAMAGE WAS DIFFICULT TO LOCATE EVEN WITH A MIRROR. CLOSE INSPECTION OF THIS AREA SHOULD BE ACCOMPLISHED ANYTIME ACCESS IS GAINED TO THE RUDDER SERVO, AT WHICH TIME THE HOSE/LINE CLEARANCE SHOULD BE CHECKED THROUGH FULL RANGE OF RUDDER TRAVEL.

PILOT REPORTED PNEUMATIC PRESSURE AND VACUUM LOW AND DROPPING. FOUND PNEUMATIC REGULATOR CONTAMINATED WITH BLACK 'DUST' AND LARGER PIECES OF DEBRIS IN INLET LINE. TRACED PROBLEM TO PNEUMATIC SUPPLY HOSE AT LT ENGINE. APPROX ONE-THIRD OF INTERNAL PORTION OF HOSE WAS GONE AND REMAINDER OF INTERIOR 'DRY ROTTED' AND WOULD CRUMBLE WHEN HOSE BENT. PNEUMATIC SYS PURGED TO REMOVE DEBRIS AND HOSES ON BOTH ENGINES REPLACED. PNEUMATIC REGULATOR WAS CLEANED AND RE-INSTALLED. PNEU AND VACUUM SYSTEMS ADJUSTED PER MM. BELIEVE HOSE ON LT ENG INCORRECT P/N AND SUBSEQUENTLY INCORRECT MATERIAL TO WITHSTAND HIGH TEMPS COMING FROM ENGINE. RT HOSE APPEARED CORRECT P/N. BOTH HOSES HAD SAME MFG DATE.