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21-10 A RAPID DECOMPRESSION OCCURRED AT 13000' ON DEPARTURE FROM SINGAPORE, DURING LEVEL FLIGHT. AN EMERGENCY DECENT WAS CARRIED OUT AND THE QRH CHECKLIST FOLLOWED. THE AIRCRAFT WAS FLOWN SAFELY BACK TO WSSL. COMPLIED WITH LEFT MAIN LANDING GEAR GROUND CONTACT SWITCH - REMOVAL/ INSTALLATION IAW G100 SPX AMM 32-60-01 REV 26 NOV 15/24 FOUND SATISFACTORY. PERFORMED MAIN LANDING GEAR GROUND CONTACT SWITCH ADJUSTMENT/ TEST IAW G100 SPX AMM 32-60-01 REV 26 NOV 15/24 FOUND SATISFACTORY. PERFORMED POSITION AND WARNING SYSTEM OPERATION TEST IAW G100 SPX AMM 32-6-00 FOUND SATISFACTORY. PERFORMED CABIN PRESSURE CONTROL SYSTEM OPERATIONAL TEST (DURING LEFT ENGINE RUN -UP) IAW G100 SPX AMM 21 -30-00 FOUND SATISFACTORY. LEFT MAIN LANDING GEAR GROUND CONTACT SWITCH PN OFF: 444EN1 -6, SN OFF: N/A, PN ON: 444EN1 -6 SN ON: N/A.

AIRCRAFT WAS ENROUTE DTN -ABQ. IN LEVEL FLIGHT AT FL400 CREW EXPERIENCED A LOUD VIBRATION IN ONE OF THE ENGINES THAT LASTED FOR APPROXIMATELY 10-20 SECONDS. CREW COULD NOT TELL WHICH ENGINE. IT HAPPENED AGAIN WITH A CORRESPONDING RED ITT GAUGE INDICATING 881 DEGREES AND RECEIVED AN ENGINE EXCEEDANCE CAS. CREW PULLED THE THROTTLES BACK HALFWAY. CREW OBSERVED NO ICE ON THE WING BUT ELECTED TO TURN ON THE ENGINE HEAT. AIRCRAFT WAS NEVER IN THE CLOUDS BELOW FL400. VERY SHORTLY AFTER TURNING ON THE HEAT, THE VIBRATION HAPPENED AGAIN WITH ITT RED ON BOTH ENGINES, AN ENGINE NO DISPATCH CAS, AND E1 CONTROL FAULT AND E2 CONTROL FAULT OCCURRED. OTHER CAS MESSAGES APPEARED, HOWEVER WERE GONE BEFORE CREW COULD GET TO THEM AND DON’T RECALL WHAT THEY WERE. CREW NOTED SMELL OF JET EXHAUST CAME THROUGH THE CABIN. CREW AND PASSENGER DONNED CREW OXYGEN MASKS. CREW DECLARED AN EMERGENCY, REQUESTED VECTORS TO CLOSEST AIRPORT, PULLED THRUST LEVERS TO FLIGHT IDLE, AND BEGAN A DESCENT THROUGH THE BACKSIDE OF A STORM. THE VIBRATIONS AND ITT RED LINE CONTINUED A FEW MORE TIMES BUT STOPPED EVENTUALLY DURING THE DESCENT. CREW ENGAGED AP AND RAN THE E1 CTRL FAULT CHECKLIST. RADIO HAD SEVERE STATIC DUE TO THE STORM AND ATC WAS EXTREMELY HARD TO UNDERSTAND. CREW CLEARED THE BACK SIDE OF THE LINE OF STORMS, WAS ABLE TO MANAGE THRUST, AND ATC RECOMMENDED A DIVERSION TO AMA WHICH WAS ACCEPTED. AIRCRAFT LANDED WITHOUT INCIDENT AT AMA. AIRCRAFT CMC WAS DOWNLOADED AND SENT FOR ANALYSIS. ENGINE COMPUTERS WERE DOWNLOADED AND SENT FOR ANALYSIS. RECOMMENDED BOTH ENGINES TO BE REMOVED AND SENT TO OVERHAUL FACILITY DUE TO ITT EXCEEDANCES. AIRCRAFT WAS SIGNIFICANTLY DAMAGED BY HAIL AND LIGHTNING DUE TO EMERGENCY DESCENT THROUGH WEATHER.

IN LEVEL FLIGHT AT FL400 “L FUEL PRESS” AMBER ANNUNCIATOR ILLUMINATED. CREW INITIATED RELEVANT CHECKLIST. LEFT ENGINE ROLLBACK OCCURRED APPROXIMATELY 2 MIN AFTER ANNUNCIATION. AN INFLIGHT ENGINE RESTART WAS ATTEMPTED BUT UNSUCCESSFUL. IN THE PROCESS OF TROUBLESHOOTING AND CHECKLIST PROCEDURES IT WAS NOTED THAT THE LEFT JET PUMP SWITCH WAS IN THE “OFF” POSITION, WAS NOT ANNUNCIATING CORRECTLY AND WOULD NOT LATCH IN THE “JET PUMP” POSITION. THE ENGINE WAS SECURED AND A SINGLE ENGINE APPROACH AND LANDING WAS ACCOMPLISHED. TROUBLESHOOTING ON THE GROUND CONFIRMED THE FAILURE OF THE JETPUMP SWITCH PART NUMBER: 4702-1. NO OTHER DEFECTS WERE NOTED.

ON LANDING AFTER TOUCHDOWN PILOTS STATE THAT THRUST REVERSER LEVERS WERE PULLED BUT NEITHER THRUST REVERSER UNLOCKED. ON SECOND ATTEMPT PILOT STATES THAT RT REVERSER UNLOCKED & DEPLOYED PRIOR TO LT REVERSER UNLOCKING & DEPLOYING. ACFT YAWED TO THE RT & STRUCK A RUNWAY LIGHT WITH THE RT WING BEFORE REGAINING FULL CONTROL OF ACFT & MOVING BACK TOWARDS THE CTR LINE. THE ACFT WAS STOPPED ON THE RUNWAY BY THE TOWER, AIRPORT OPERATIONS PERSONNEL CAME OUT & INSPECTED THE AIRPLANE, WHICH WAS THEN RELEASED & TAXIED OFF THE RUNWAY UNDER THEIR OWN POWER. FURTHER INSPECTION AFTER SHUTDOWN REVEALED SIGNIFICANT DAMAGE TO THE RT HAND FLAP.

ACFT DEPARTED, AFTER SHORT VECTOR TO FINAL, CAPTAIN CALLED FOR GEAR DOWN AND NO INDICATION OF EXTENSION OCCURRED. CREW REQUESTED VECTOR TO SAFE AREA TO ASCERTAIN & DIAGNOSE PROBLEM. AFTER SERVERAL ATTEMPTS TO CYCLE GEAR, THE LOWERED GEAR USING " ALTERNATE GEAR EXTENSION" CHECKLIST AND LOWERED GEAR. AFTER LOW APPROACH & VERIFICATION BY TOWER OF GEARDOWN, CREW DECLARED EMERGENCY AND LANDED SAFELY. ANALYSIS FOUND BROKEN WIRE AT RT MAIN GEAR DOWN & LOCK SWITCH. REPAIR COMPLETED. WIRE REPAIRED, ACFT RETURNED TO SERVICE.

THE PACKING HOLDER P/N D52177 INSIDE OF THE MAIN GEAR ACTUATOR BROKE APART IN TWO PIECES.THIS CAUSED LOSS OF HYDRAULIC FLUID TO THE AIRCRAFT. THIS PART HAD NOT BEEN MODIFIED IAW SB TO PREVENT THIS PART FROM BREAKING. THIS IS THE 3RD PACKING HOLDER FOUND TO BE CRACKED OR BROKEN, WHERE MODIFIED OR NOT.

DURING FLIGHT CREW NOTICED THERE WAS A LARGE DISCREPANCY BETWEEN INDICATED FUEL QUANTITY AND AMOUNT OF FUEL USED AS SHOWN ON FLIGHT MANAGEMENT SYSTEM. UPON LANDING CREW NOTICED FUEL DRIPPING FROM SEVERAL AREAS ON THE UNDERSIDE OF THE AIRCRAFT. FUEL WAS FOUND IN THE AFT BAGGAGE COMPARTMENT. WHILE TROUBLESHOOTING THIS PROBLEM, MAINTENANCE PERSONNEL DISCOVERED THAT WHEN THE LT FUEL BOOST PUMP WAS OPERATED IT WAS CONTINUOUSLY PUMPING FUEL OUT OF THE PUMP HOUSING OVERBOARD DRAIN. THE INTERNAL SEALS IN THIS PUMP HAD FAILED CAUSING THIS PROBLEM. DEFECTIVE PUMP WAS REPLACED WITH AN OVERHAULED UNIT AND AIRCRAFT WAS OPERATED WITH NO FURTHER PROBLEMS.

DURING NR 2 ENGINE CHANGE, FOUND 7.5 INCH LONG CRACK IN THE TOP OF THE ''S'' DUCT ALONG THE LONGITUDINAL AXIS APPROXIMATELY 3 FEET IN FRONT OF THE ENGINE INLET. THERE IS ALSO A CRACK IN THE AFT ATTACHMENT FLANGE OF THE ANTI-ICE MANIFOLD ON THE TOP SIDE OF THE DUCT. THE MANUFACTURER HAS BEEN NOTIFIED AND ARE CURRENTLY WORKING WITH ENGINEERS TO EFFECT A REPAIR IF POSSIBLE. (X)