NOSE GEAR DOOR FELL OFF DURING GEAR RETRACTION. CREW DECLARED EMER; DUMPED FUEL TO MAX LNDG WT AND RETURNED FOR UNEVENTFUL LNDG.

Narrative

DURING TKOF FROM TPA AT GEAR RETRACTION; WE HEARD A LOUD BANG FROM THE NOSE GEAR WHEEL WELL FOLLOWED BY A RED 'DOORS' LIGHT ON THE FORWARD INST PANEL. WE TOLD TPA TWR WE WOULD LIKE TO LEVEL OFF AT 5000 FT MSL AND RETURN FOR LNDG. TPA TWR ADVISED US THAT SOMEONE RPTED SEEING SOMETHING FALL OFF OUR ACFT. WE SWITCHED TO DEP CTL AND ASKED TO DUMP FUEL. FOLLOWING THE ABNORMAL GEAR RETRACTION CHKLIST; WE LOWERED THE LNDG GEAR AND GOT 3 DOWN AND LOCKED GEAR LIGHTS; BUT STILL HAD THE RED NOSE GEAR 'DOORS' LIGHT ILLUMINATED. WE HAD RETRACTED THE FLAPS TO 5 DEGS AND KEPT THE AIRSPD AT 180 KIAS. WE COMPLETED THE ABNORMAL CHKLIST; DID THE DSCNT AND APCH CHKLISTS; BRIEFED THE FLT ATTENDANTS AND ASKED THEM TO PREPARE THE CABIN FOR AN EMER LNDG AND POSSIBLE EVAC. WE MADE 2 PA'S TO THE PAX TO INFORM THEM OF WHAT WE WERE DOING AND ASSURE THEM OF THEIR SAFETY. WE ASKED FOR RWY 36L (THE LONGEST RWY AT TPA); REQUESTED EMER EQUIP AND ACR MAINT (TO PIN THE GEAR AND CHK FOR DAMAGE). AFTER DUMPING FUEL TO AN ACFT WT OF 154000 LBS WE MADE A SAFE AND UNEVENTFUL LNDG. WE STOPPED STRAIGHT AHEAD ON THE RWY AND HAD MAINT PIN THE LNDG GEAR.