N527US

Part: LIGHT — INOPERATIVE (CABIN) · airframe 73,150 hrs · 29,843 cycles

DURING A LINE CHECK, MX FOUND THE DOOR 2R EMERGENCY EXIT LIGHT INOPERATIVE. MX REPLACED THE EXIT LIGHT ASSY. OPS CHECK WAS GOOD.

Part: BATTERY PACK — DISCHARGED (CABIN) · airframe 72,996 hrs · 29,774 cycles

EMERGENCY LIGHT MODULES INOPERATIVE AT BOTH AFT DOORS AT LOWER FORWARD CORNER. REPLACED AFT BATTERY PACK. CHECKED GOOD.

Part: BATTERY PACK — DISCHARGED (CABIN) · airframe 72,996 hrs · 29,774 cycles

EMERGENCY LIGHT MODULES INOPERATIVE AT BOTH AFT DOORS AT LOWER FORWARD CORNER. REPLACED AFT BATTERY PACK. CHECKED GOOD.

Part: POWER SUPPLY — INOPERATIVE (EMERGENCY LIGHT) · airframe 66,146 hrs · 27,296 cycles

DURING OVERNIGHT LINE CHECK, FOUND FLOOR TRACK EMERGENCY LIGHTS ROW 33 TO 40 INOP. MAINTENANCE REMOVED AND REPLACED POWER SUPPLY. OPERATIONAL CHECKED GOOD AND AIRCRAFT WAS RETURNED TO SERVICE.

Part: BATTERY PACK — INOPERATIVE (EMERGENCY LIGHTS) · airframe 65,432 hrs · 27,036 cycles

PILOT REPORTED EMERGENCY LIGHTS INOP. MAINTENANCE REMOVED AND REPLACED FORWARD BATTERY PACK. OPERATIONAL CHECKED GOOD AND AIRCRAFT WAS RETURNED TO SERVICE.

Part: PANEL — DEBONDED (HORIZONTAL STAB) · airframe 65,158 hrs · 26,935 cycles

DURING "L" CHECK FOUND RT HORIZONTAL STABILIZER UPPER INBOARD PANEL DISBONDED BETWEEN FSS 83-204. REPAIRED PER EA 55-210445 SECTION I. REPEAT INSPECTIONS REQUIRED PER SECTION II AT INTERVALS NOT MORE THAN 6 MONTHS FOR PERIOD UP TO 24 MONTHS. SECTION III PERMANENT REPAIR REQUIRES REPLACEMENT OF PANEL.

Part: FLOORBEAM — CRACKED (FUSELAGE) · airframe 51,304 hrs · 21,361 cycles

DURING "L" CHECK FOUND CRACK IN FLOORBEAM UPPER CAP AT BS 700 LBL 25. REPAIRED PER EA 55-191542.

Part: SLIDE — FAILED (CABIN) · airframe 51,304 hrs · 21,361 cycles

WHILE PERFORMING SAMPLING DEPLOYMENT INSPECTION OF DOOR 4R EVACUATION SLIDE, THE LOWER LEFT SUPPORT RIB SEAM RIPPED OPEN. REPLACED THE SLIDE. OPERATIONAL CHECK OK.

Part: HYDRAULIC LINE — LEAKING (HYD SYSTEM) · airframe 50,860 hrs · 21,176 cycles

JUST AFTER DEPARTURE FROM MSP, THE AIRCRAFT EXPERIENCED A COMPLETE LOSS OF HYDRAULIC FLUID FROM THE LEFT HYDRAULIC SYSTEM. AN EMERGENCY WAS DECLARED WITH ATC AND THE AIRCRAFT LANDED UNEVENTFULLY AND WAS TOWED FROM THE RUNWAY. REPLACED THE HYDRAULIC LINE AT THE LEFT MAIN LANDING GEAR DOWNLOCK ACTUATOR. OPERATIONAL CHECK GOOD.

Part: CONTROL UNIT — FAULTY (E/E BAY) · airframe 47,379 hrs · 19,844 cycles

ON DEPARTURE FROM SFO, BOTH ENGINE EPR INDICATIONS WERE ABNORMAL BUT OTHER ENGINE INSTRUMENTS WERE WITHIN PARAMETERS. DURING CLIMB, STATUS MESSAGES APPEARED FOR BOTH ENGINE OIL COOLERS AND REVERSER CONTROL VALVES. THE FLIGHT RETURNED TO SFO AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE BUSS POWER CONTROL UNIT WITH A SERVICEABLE UNIT. SUBSEQUENT SYSTEM TESTS WERE SATISFACTORY. AIRCRAFT RETURNED TO SERVICE.

Part: FIRE DETECTOR · airframe 45,473 hrs · 19,116 cycles

WHEN STARTING THE LEFT ENGINE THE LEFT FIRE WARNING OCCURRED. FIRE WARNING STOPPED WHEN ENGINE FUEL CONTROL WAS PLACED TO 'CUTOFF'. AIRCRAFT RETURNED TO THE GATE. MAINTENANCE REPLACED THE LEFT ENGINE CORE UPPER AND LOWER FIRE DETECTORS. OPERATIONAL CHECK OK.

Part: CONTROL MIXER — MALFUNCTIONED (RT AILERON)

EN ROUTE DTW-SFO CLIMBING THROUGH FL180, CREW REPORTED UNCOMMANDED RIGHT AILERON MOVEMENT. AN EMERGENCY WAS DECLARED. THE FLIGHT DIVERTED TO ORD AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE LATERAL CONTROL MIXER AND RIGGED THE AILERON CONTROL SYSTEM. AILERON SYSTEM TESTS WERE SATISFACTORY.

Part: VALVE — FAILED (PRESSURE SYS)

DURING DESCENT INTO DTW, THE CABIN ALTITUDE WARNING HORN SOUNDED. CABIN ALTITUDE WAS 10,000 FEET. AN EMERGENCY DESCENT WAS INITIATED FROM FL240 TO 10,000 FEET. FLIGHT CONTINUED TO DTW AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED BOTH PRESSURE RELIEF VALVES WITH SERVICEABLE UNITS.

Part: SKIN — CRACKED (NR 1 PYLON)

DURING PERIODIC CHECK, FOUND A ONE INCH CRACK IN THE NR 1 ENGINE NACELLE STRUT SKIN PANEL, NACELLE STA 115. REPAIRED PANEL P/N 311N3450-11, -13, -15 PER EA 55-98479.

Part: FLOORBEAM — CORRODED (FS 365)

DURING PERIODIC CHECK, FOUND CORROSION ON THE FLOORBEAM UPPER CHORD FS 365. REPAIRED PER EA 55-98478.

Part: COOLING FAN — FAILED (FWD E/E BAY)

A STRONG ELECTRICAL BURNING SMELL WAS NOTICED IN THE COCKPIT. FOLLOWED COCKPIT OPERATING PROCEDURE AND SMELL WAS EVACUATED, SOURCE WAS UNKNOWN. FOUND THE FORWARD EQUIPMENT COOLING SUPPLY FAN CIRCUIT BREAKER POPPED, AND WAS UNABLE TO RESET. REPLACED FORWARD EQUIPMENT COOLING FAN. SYSTEM CHECKED NORMAL.