ACR WDB COMPRESSOR STALL AT VR. FUEL DUMP RETURN LAND.

Narrative

FLT WAS SCHEDULED TO DEPART LONDON GATWICK ENRTE TO MIAMI. ATIS INFO HAD NOTED RPTS OF WINDSHEAR EARLIER IN THE MORNING. PUSHBACK FROM STAND AND ENG START AND TAXIOUT WERE NORMAL; AFTER START AND TAXI CHKLISTS ACCOMPLISHED ROUTINELY. WE HELD SHORT OF THE RWY APPROX 4-5 MINS FOR LNDG AND DEPARTING TFC. TWR REPEATEDLY ISSUED WINDS THROUGHOUT THIS APCH AND LNDG; AND THEN THE DEP; AND THEY WERE CONSISTENTLY 210/20. WX WAS VFR; NO PRECIPITATION; NO ACTIVE WINDSHEAR ALERT OR RPTS. WE WERE INITIALLY CLRD ON TO HOLD; AND BEFORE TKOF CHKLIST WAS COMPLETED WHILE TAXIING INTO POS. BEGAN TKOF ROLL ON RWY 26L APPROX TKOF WT 730000 LBS; TKOF EPR 1.45; FLAPS 20; ALL ENGS OPERATING NORMALLY AT TKOF PWR. ROLLING DOWN THE RWY; THE F/O ANNOUNCED A MOMENTARY PAUSE OF THE AIRSPD AT ABOUT 120 KTS AND AGAIN AT ABOUT 140 KTS. NO FLASHING 8'S (INDICATING WINDSHEAR) WERE OBSERVED ON THE INS DURING THE ROLL. ROTATION AT VREF WAS NORMAL; BUT AS THE MAIN GEAR LIFTED OFF THE RWY WE HEARD A LOUD BANG FROM THE RIGHT SIDE OF THE ACFT AND THE S/O ANNOUNCED WE HAD LOST PWR ON ENG #4. THE AMBER OVERTEMP LIGHT ON #4 WAS ILLUMINATED AND THE MAX EGT INDICATOR WAS PEGGED OFF THE TOP OF THE SCALE. THE S/O RESPONDED TO MY REQUEST FOR MORE PWR BY SELECTING MAX PWR ON ENGS #1; #2 AND #3. A POSITIVE RATE OF CLB WAS VERIFIED AND THE LNDG GEAR WAS RAISED. THE S/O THEN INITIATED FUEL DUMPING PROCS AS BRIEFED. THE STICK SHAKER ACTIVATED; AND THE AIRSPD OSCILLATED QUITE WILDLY SLIGHTLY ABOVE AND BELOW THE VREF AIRSPD BUG. THE ACFT FELT AS THOUGH IT WAS BEING BUFFETED BY GUSTY WINDS AND FLASHING 8'S (INDICATING WINDSHEAR) WERE OBSERVED INTERMITTENTLY ON THE INS. I WORKED TO ESTABLISH A PITCH ATTITUDE TO MAINTAIN CLRNC WITH THE VISIBLE AND RISING TERRAIN OFF THE END OF THE RWY; WHILE AT THE SAME TIME ATTEMPTING TO MAINTAIN AS LEVEL A FLT PROFILE AS POSSIBLE TO STABILIZE AND INCREASE AIRSPD. NO GPWS WARNING WAS ACTIVATED. RWY HDG WAS MAINTAINED AS CLOSELY AS POSSIBLE. AIRSPD GRADUALLY INCREASED; THE STICKER SHAKER STOPPED AND AT V2 A SHALLOW CLB WAS INITIATED TO APPROX 800' AGL. THE CLB RATE WAS THEN NEUTRALIZED TO ALLOW A FURTHER INCREASE IN AIRSPD; AND THE FLAPS WERE RETRACTED ON SCHEDULE. CLB WAS THEN CONTINUED TO OUR INITIAL ASSIGNED ALT OF 3000' MSL AND THE F/O CALLED IN OUR EMER TO GATWICK TWR; INFORMING THEM WE WERE DUMPING FUEL AND CLBING TO 3000' MSL. WE WERE SWITCHED TO A RADAR FREQ AND REQUESTED A RADAR BOX PATTERN TO CONTINUE FUEL DUMPING AND A FURTHER CLB TO 4000' MSL TO REMAIN CLR OF A THIN CLOUD LAYER IN THE AREA. THE ENG FAILURE CHKLIST WAS ACCOMPLISHED. THE ENG WAS SHUTDOWN ACCORDING TO THE CHECKLIST PROCS. F/A'S WERE NOTIFIED OF THE PROB AND OUR INTENTIONS; AND THEN AN ANNOUNCEMENT WAS MADE TO THE PAX BY THE S/O. TOTAL FUEL DUMP TIME WAS APPROX 36 MINS TO DUMP ABOUT 160000# OF FUEL. OUR MAX LNDG WT LIMIT WAS 585000 LBS. WE WERE SUBSEQUENTLY INFORMED BY THE F/A'S THAT CREWMEMBERS AND PAX AT THE REAR OF THE ACFT HAD WITNESSED FLAMES SHOOT OUT OF BOTH ENGS #1 AND #4 AT THE TIME OF THE LOUD BANG. WHILE CONTINUING TO DUMP FUEL WE COMPLETED THE ONE GEN INOP AND THE ONE ENG INOP APCH AND LNDG CHKLIST. WE DISCUSSED THE IMPENDING APCH AND THE POSSIBILITY OF ENCOUNTERING MORE GUSTY CONDITIONS AND WINDSHEAR; AND KNOWING WE MIGHT ALSO HAVE A PROB WITH ENG #1; I ELECTED TO ATTEMPT TO RESTART ENG #4. THERE WAS NO KNOWN MALFUNCTION OR INDICATION OF MECHANICAL ENG DAMAGE; AND ENG WAS RESTARTED NORMALLY BY CHKLIST PROCS. ITS SUBSEQUENT OP WAS NORMAL AND WITHIN ALL OP LIMITS. WHEN FUEL DUMPING WAS COMPLETED; REQUESTED RADAR VECTORS AT 4000' MSL TO ILS FINAL APCH RWY 26L AT GATWICK. APCH AND LNDG CHKLISTS WERE COMPLETED ROUTINELY AND ACFT WAS CONFIGURED FOR A FLAPS 25 APCH AND LNDG DUE WINDY CONDITIONS. AN UNEVENTFUL T/D WAS MADE ON 26L. REVERSE WAS USED ONLY ON ENGS #2 AND #3; ENG #4 WAS SHUTDOWN AFTER CLRING RWY. GATWICK FIRE PERSONNEL VISUALLY INSPECTED ENGS AND UNDERCARRIAGE AND APPROVED FURTHER TAXI TO STAND. NO CREW MEMBERS ARE AWARE OF ANY PAX PROBS/COMPLAINTS RELATED TO ABOVE EVENTS. I PERSONALLY FEEL THAT ENG #4 EXPERIENCED COMPRESSOR STALL AND SUBSEQUENT FAILURE DUE WIND CONDITIONS OR WINDSHEAR ENCOUNTERED AT LIFTOFF; AND THAT ENG #1 PROBABLY WAS AFFECTED BY SIMILAR BUT LESS SEVERE WIND CONDITIONS. OUR ABILITY TO RECOVER THE ACFT FROM THIS SITUATION IS A TRIBUTE TO OUR TRAINERS AND THE CREW CONCEPT. EACH CREW MEMBER PERFORMED PROFESSIONALLY; WITH QUICK; ACCURATE ACTIONS AND DECISIONS. THE COHESIVENESS AND RAPPORT ON THE FLT DECK WAS INSTRUMENTAL TO THE SMOOTH FLOW OF BOTH INFO AND PROCS. I AM THANKFUL THAT I WAS FLYING WITH 2 HIGHLY TRAINED; SKILLED AND EXPERIENCED PROFESSIONALS WHO RESPONDED INSTANTLY AND ACCURATELY TO THE SITUATION WE FACED. SUPPLEMENTAL INFORMATION FROM ACN 81539: THEY HAD RPTED SHEAR 30-45 MINS EARLIER WHILE OUR CABIN TEAM WAS BOARDING OUR 425 PAX. I DO NOT RECALL AN ASSOCIATED ALT OR SHEAR FACTOR. THE STICK SHAKER SOUNDED AND I CALLED FOR PWR. THE STICK SHAKER CONTINUED AND AIRSPD WAIVERED WITHIN +/- 3K OF VR. SUPPLEMENTAL INFORMATION FROM ACN 81667: IT SHOULD ALSO BE NOTED THAT AS I WAS SETTING PWR THE F/O ASKED THE CAPT IF HE WOULD LIKE THE GEAR RAISED AND HE ANSWERED YES (SO DID I). WE LATER LEARNED WAS VIRTUALLY TREETOP LEVEL (WE CAUSED 'SUBSTANTIAL TREE DAMAGE ALONG THE DEP PATH'). FLYING THE AIRPLANE FOR ALMOST 30 SECS AT STICK SHAKER BTWN V1 AND VR. DUMPING JET FUEL ON NOT A FEW ANGRY RESIDENTS. IT WAS A RELIEF TO HEAR ANOTHER VOICE; BUT ALL THE SAME IT SHOULD BE EMPHASIZED THEIR POLICY OF MAINTAINING RADIO SILENCE DURING AN EMER WAS VERY IMPORTANT TO OUR INTRACOCKPIT EQUILIBRIUM (IE; WE DIDN'T WANT TO HEAR FROM THEM TILL WE WERE GOOD AND READY). IN ORDER TO DUMP THE S/O-F/E ON A WDB MUST SWIVEL HIS SEAT AND SLIDE BACK TO REACH THE DUMP PANEL. TO GET BACK UP TO REACH THE PWR LEVERS THE ELECTRIC MOTOR IS REQUIRED TO OVERCOME THE STEEP DECK ANGLE ASSOCIATED WITH EVEN A NORMAL DEP. THE ELECTRIC MOTOR IS AN ACCEPTABLE DEFERRED MAINT ITEM.