What was found
WHILE IN CRUISE FLT AT FL 260 AT 300 KTS, NLG DROPPED OUT OF WW. CREW SLOWED A/C TO BELOW 200 KTS AND REQUESTED A LOWER ALT. L/G WAS CYCLED UP AND ALL GEAR REMAINED RETRACTED. A/C WAS LANDED W/O FURTHER INCIDENT. GEAR WAS INSPECTED FOLLOWING LANDING AND A GEAR DOOR FOUND TO BE TWISTED. MX REMOVED, RESEALED AND REINSTALLED NLG STRUT ASSY. UPLOCK RIGGING WAS CHECKED AND L/G LUBRICATED. PHASE I AND II INSPECTIONS WERE COMPLETED FOR A NLG AFTER OVERSPEED EXTENSION. NO FAULTS FOUND. NLG AFT DOOR ADJUSTED AND SEVERAL WORKING RIVETS REPLACED. 5 CYCLES OF L/G COMPLETED WITH NO NOTED DISCREPANCIES. A/C WAS RETURNED TO SERVICE.