N1376G

Part: SOCKET — DETERIORATED (OAT INDICATOR) · airframe 36,945 hrs · 36,225 cycles

DURING DESCENT FOR LANDING AT SCHEDULED DESTINATION, THE LWR PANEL LIGHT RHEOSTAT WAS ACTUATED. AFTER 2-3 SECONDS A STRONG ELECTRICAL ODOR WAS NOTED. THE PANEL LIGHTS WERE EXTINGUISHED AND THE ODOR RECEEDED. NO EMERGENCY WAS DECLARED AND THE LANDING WAS UNEVENTFUL. SUBSEQUENT INSPECTION REVEALED THE PLASTIC SOCKET AT THE OAT GAUGE POST LIGHT WAS MELTED. THE ASSEMBLY APPEARS TO HAVE DETERIORATED INTERNALLY ALLOWING THE CONDUCTOR TO SHORT ACROSS ITSELF. A BRIEF ILLUSTRATION OF THE FAILURE WILL BE ASSOCIATED WITH THIS SUBMISSION.

Part: FITTING — CRACKED (ZONE 400) · airframe 35,948 hrs · 34,737 cycles

DURING A ROUTINE INSPECTION, THREE CRACKS WERE FOUND ON THE RT OUTBOARD NACELLE FITTING. TWO OF THE CRACKS WERE FOUND ON THE INBOARD SIDE OF THE FITTING, JUST FORWARD OF THE SPAR STRAP. MEASURED .050 AND .090 IN LENGTH. THE THIRD CRACK WAS FOUND ON THE OUTBOARD SIDE OF THE FITTING, JUST FORWARD OF THE SPAR STRAP. CRACK WAS .102 IN LENGTH.

Part: EXHAUST VALVE — DAMAGED (NR 2 CYLINDER) · airframe 35,809 hrs

CYLINDER REMOVED DUE TO LOW COMPRESSION AT INSPECTION; EXHAUST VALVE DISPLAYS EVIDENCE OF HEAT DAMAGE.

Part: EXHAUST VALVE — DAMAGED (NR 4 CYLINDER) · airframe 37,562 hrs

CYLINDER REMOVED DUE TO LOW COMPRESSION AT INSPECTION; EXHAUST VALVE DISPLAYS EVIDENCE OF HEAT DAMAGE.

Part: UNKNOWN — ODOR (COCKPIT) · airframe 35,095 hrs · 33,527 cycles

PILOT REPORTED HEATER SMELL. RAN HEATER FOR 30 MINUTES, COULD NOT DUPLICATE SMELL. INSPECTED HEATER IAW MM CH 21.

Part: CALIPER — DEFECTIVE (MLG BRAKE) · airframe 33,397 hrs · 30,867 cycles

ON PREFLIGHT PILOT REPORTED RT BRAKES INOPERATIVE, NO BRAKES ON THE RT SIDE. R & R THE RT BRAKE CALIPER & BRAKE PADS IAW MM 32-10-00. OPERATIONS CHECKED GOOD.

Part: LIGHT — FAULTY (INSTRUMENT PANEL) · airframe 31,739 hrs · 28,319 cycles

INSTRUMENT PANEL LIGHTS EXTINGUISHED AFTER TAKEOFF. F/O INSTRUMENT LIGHT CIRCUIT BREAKER TRIPPED FOLLOWED BY MOMENTARY PUFF OF SMOKE.

Part: SKIN — CHAFED (ZONE 100) · airframe 31,553 hrs

DURING A SCHEDULED MX INSPECTION, HORIZONTAL STABILIZER WAS REMOVED WHICH REVEALED DAMAGE TO THE ACFT FUSELAGE SKIN. DAMAGE APPEARS TO HAVE BEEN CAUSED BY THE L/E OF THE HORIZONTAL STABILIZER CHAFING INTO THE FUSELAGE SKIN. DAMAGED AREA RANGED FROM FS 342.24 TO 345.15 AND WL 104.38 TO 106.88. REPAIRED AS DETAILED IN AC 43.13-1B PARA 4-58.

Part: DRAG BRACE — CRACKED (NLG) · airframe 29,447 hrs

AT SCHEDULED INSPECTION, NLG DRAG BRACE, OEM PN 5142002-5, WAS FOUND TO BE CRACKED IN THE AREA OF NLG ACTUATOR ATTACH POINT. METHOD OF INSPECTION WAS DYE PENETRANT. THIS CRACK WAS FOUND TO BE WITHIN ALLOWABLE LIMIT. THIS UNIT HAS BEEN REPAIRED IAW PROCEDURE OUTLINED IN MEB941-11R1 & RETURNED TO SERVICE.

Part: BEAM — CRACKED (LT NACELLE) · airframe 27,996 hrs

DURING A ROUTINE SCHEDULED INSP, MX FOUND LT NACELLE INBD ENG CARRIER BEAM CRACKED. REPLACEMENT OF BEAM IN PROGRESS.

Part: CIRCUIT BREAKER — FAILED (ZONE 100) · airframe 26,912 hrs · 67,000 cycles

ON PREFLIGHT INSPECTION, CREW REPORTED AVIONIC MASTER SWITCH INOP. CONTRACT MAINTENANCE REMOVED AND REPLACED SWITCH, SYSTEM CHECKED OK. THIS CIRCUIT BREAKER IS THE LATEST OF 36 TO BE CHANGED IN THE LAST TWO YEARS FOR PREMATURE FAILURE. ALL HAVE HAD THE SAME MANUFACTURE'S DATE CODE OF 0633. NONE HAVE RESULTED IN ANY EMERGENCY ACTIONS BEING TAKEN BY THE CREW, AS WERE THE PREVIOUS CIRCUIT BREAKERS INSTALLED WHICH USUALLY CAUSED SMOKE IN THE COCKPIT WHEN THE FAILED. THESE PREVIOUS FAILURES PROMPTED THE ISSUANCE OF AD2005-20-25 FOR REMOVAL AND REPLACEMENT OF EFFECTED CIRCUIT BREAKERS. THE AVERAGE FAILURE RATE (TIME IN SERVICE) FOR P/N CM3589-50 WITH A MANUFACTURING DATE CODE OF 0633 IS APPROXIMATELY 1150 HOURS. FAILURES OCCURRED AS EARLY AS 400 HOURS IN SERVICE TO 2500 HOURS.

Part: CIRCUIT BREAKER — DEFECTIVE (COCKPIT)

CREW REPORTED AVIONICS MASTER SWITCH INOP. MX CHANGED CIRCUIT BREAKER SWITCH.

Part: MASTER SWITCH — BURNED (LT SWITCH PANEL)

UPON CLIMBOUT, PILOT SMELLED SMOKE, FOUND SMOKE COMING FROM AVIONICS MASTER SWITCH. PILOT NOTIFIED TOWER BEFORE SHUTTING DOWN AVIONICS SWITCH, LANDING WITHOUT INCIDENT. MAINTENANCE REPLACED SWITCH AND RETURNED AIRCRAFT TO SERVICE.

Part: BRACKET — BROKEN (RT ENGINE)

ON RT ENGINE START, PILOT NOTICED SMOKE FROM RT COWL, SHUT DOWN ENGINE PER NORMAL PROCEDURE AND EVACUATED PASSENGERS. MAINTENANCE FOUND ALTERNATOR POWER CABLE CHAFED BY BROKEN ENGINE BAFFLE BRACKET. REPAIRED BRACKET, REPAIRED MINOR COWL DAMAGE, AND ALTERNATOR POWER CABLE. RELEASED AIRCRAFT BACK TO SERVICE.

Part: CIRCUIT BREAKER — FAILED (COCKPIT)

AFTER LANDING IN ACK, CREW SHUT OFF ALL EXTERNAL LIGHTS EXCEPT BELLY STROBE AND NAV LIGHTS. NOTICED SMOKE COMING FROM NAV LIGHT SWITCH/BREAKER. SHUT OFF SWITCH, TAXIED TO GATE, AND NOTIFIED MAINTENANCE. FOUND RT WING NAV LIGHT POWER WIRE SHORTED TO GROUND, CIRCUIT BREAKER SWITCH INOPERATIVE, DID NOT TRIP. REMOVED AND REPLACED CIRCUIT BREAKER SWITCH. CHECKED OK AFTER REPAIRING WIRING.

Part: DIODE — BURNT (WINDSHIELD HEAT)

PILOT REPORTED ARCING AND SMOKE FROM ELECTRIC HEATED WINDSHIELD. ELECTRICAL CONNECTION OR LEFT SIDE OF HEATED WINDSHIELD HAS DIODE THAT MELTED AND ARCED.

Part: MOUNT BEAM — CRACKED (FWD MT PAD)

ESTIMATED CYCLES = 28,000. ESTIMATED ENGINE CHANGES = 70. LEFT ENGINE OUTBOARD BEAM FOUND CRACKED AT FORWARD MOUNT LOCATION BETWEEN NUTPLATE HOLES.