Narrative:

During takeoff roll at london heathrow, we heard a very loud bang that seemed to come from the nosewheel area. Airspeed was very close to V1 (approximately 145 KIAS) as the captain's hand was already removed from the throttles. The nose of the airplane dipped slightly and yawed to the right. There was also a very heavy vibration that lasted until nosewheel lift-off. The only warning light we had at this point was the thrust asymmetry compensator (tac) off. We elected to leave the landing gear extended as our cues to this point were consistent with a nose tire failure. Shortly after lift-off the chief purser informed us that smoke was entering the cabin. The relief first officer was sent to the cabin to assess the smoke to see how heavy it was and try to identify the source. The tower controller then cleared a vehicle onto the runway to check for foreign object damage and then asked us if we had lost an engine. The captain advised them we were still assessing our situation and to stand by. An airline pilot who was waiting to cross the runway said he observed a large fireball from our right engine followed by clear exhaust. At this point we raised the gear while climbing to 6000 ft. The autoplt was engaged. Approaching leveloff we noted the right engine oil pressure was 56 psi and in the red. Shortly thereafter we noted the pressure at 54 psi and zero quantity. The captain directed the right engine shut down and asked the relief first officer to return to the flight deck. We accomplished all checklists and dumped approximately 100000 pounds of fuel to get to our maximum landing weight at FL070. We declared an emergency and were vectored by london control for the fuel jettison and were handed off to heathrow director for the single engine approach and landing. The cabin was prepared for a possible evacuate/evacuation and all these procedures were discussed with the chief purser. The captain took control of the aircraft on extended base leg and I took over PNF duties. Landing was uneventful and we cleared at the last high speed taxiway and terminated the emergency. Looking back with the knowledge we had a thrust loss very close to V1 (a recoverable engine stall) I feel the heavy vibration we experienced was due to the nosewheel scuffing the runway as the aircraft yawed due to decreased thrust in the right engine and subsequent rudder input to control the yaw. Also the airframe must really conduct noise as all 3 flight deck crew members thought the loud bang came from the nosewheel area.

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Original NASA ASRS Text

Title: FLC OF WDB EXPERIENCES A LOUD BANG AND VIBRATION AT V1 SPD. AN ACR CAPT ON THE GND INDICATED A FIREBALL FROM THE R ENG FOLLOWED BY CLR EXHAUST. THE FLC CIRCLED TO DUMP FUEL AND RETURNED.

Narrative: DURING TKOF ROLL AT LONDON HEATHROW, WE HEARD A VERY LOUD BANG THAT SEEMED TO COME FROM THE NOSEWHEEL AREA. AIRSPD WAS VERY CLOSE TO V1 (APPROX 145 KIAS) AS THE CAPT'S HAND WAS ALREADY REMOVED FROM THE THROTTLES. THE NOSE OF THE AIRPLANE DIPPED SLIGHTLY AND YAWED TO THE R. THERE WAS ALSO A VERY HVY VIBRATION THAT LASTED UNTIL NOSEWHEEL LIFT-OFF. THE ONLY WARNING LIGHT WE HAD AT THIS POINT WAS THE THRUST ASYMMETRY COMPENSATOR (TAC) OFF. WE ELECTED TO LEAVE THE LNDG GEAR EXTENDED AS OUR CUES TO THIS POINT WERE CONSISTENT WITH A NOSE TIRE FAILURE. SHORTLY AFTER LIFT-OFF THE CHIEF PURSER INFORMED US THAT SMOKE WAS ENTERING THE CABIN. THE RELIEF FO WAS SENT TO THE CABIN TO ASSESS THE SMOKE TO SEE HOW HVY IT WAS AND TRY TO IDENT THE SOURCE. THE TWR CTLR THEN CLRED A VEHICLE ONTO THE RWY TO CHK FOR FOREIGN OBJECT DAMAGE AND THEN ASKED US IF WE HAD LOST AN ENG. THE CAPT ADVISED THEM WE WERE STILL ASSESSING OUR SIT AND TO STAND BY. AN AIRLINE PLT WHO WAS WAITING TO CROSS THE RWY SAID HE OBSERVED A LARGE FIREBALL FROM OUR R ENG FOLLOWED BY CLR EXHAUST. AT THIS POINT WE RAISED THE GEAR WHILE CLBING TO 6000 FT. THE AUTOPLT WAS ENGAGED. APCHING LEVELOFF WE NOTED THE R ENG OIL PRESSURE WAS 56 PSI AND IN THE RED. SHORTLY THEREAFTER WE NOTED THE PRESSURE AT 54 PSI AND ZERO QUANTITY. THE CAPT DIRECTED THE R ENG SHUT DOWN AND ASKED THE RELIEF FO TO RETURN TO THE FLT DECK. WE ACCOMPLISHED ALL CHKLISTS AND DUMPED APPROX 100000 LBS OF FUEL TO GET TO OUR MAX LNDG WT AT FL070. WE DECLARED AN EMER AND WERE VECTORED BY LONDON CTL FOR THE FUEL JETTISON AND WERE HANDED OFF TO HEATHROW DIRECTOR FOR THE SINGLE ENG APCH AND LNDG. THE CABIN WAS PREPARED FOR A POSSIBLE EVAC AND ALL THESE PROCS WERE DISCUSSED WITH THE CHIEF PURSER. THE CAPT TOOK CTL OF THE ACFT ON EXTENDED BASE LEG AND I TOOK OVER PNF DUTIES. LNDG WAS UNEVENTFUL AND WE CLRED AT THE LAST HIGH SPD TXWY AND TERMINATED THE EMER. LOOKING BACK WITH THE KNOWLEDGE WE HAD A THRUST LOSS VERY CLOSE TO V1 (A RECOVERABLE ENG STALL) I FEEL THE HVY VIBRATION WE EXPERIENCED WAS DUE TO THE NOSEWHEEL SCUFFING THE RWY AS THE ACFT YAWED DUE TO DECREASED THRUST IN THE R ENG AND SUBSEQUENT RUDDER INPUT TO CTL THE YAW. ALSO THE AIRFRAME MUST REALLY CONDUCT NOISE AS ALL 3 FLT DECK CREW MEMBERS THOUGHT THE LOUD BANG CAME FROM THE NOSEWHEEL AREA.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.