NOSE GEAR UNSAFE WARNING.

Narrative

ON FINAL WE PUT THE GEAR DOWN--NOSE GEAR SHOWED RED LIGHT AND NO GREEN. WE RECYCLED THE GEAR--NO CHANGE. WE FLEW BY THE TWR AT 1000' AGL--THEY CONFIRMED IT APPEARED TO BE DOWN. WE HAD HEARD IT COME OUT OF THE WHEEL WELL SO WE KNEW; AT LEAST; IT WAS NOT UP. WE HAD AN OBSERVER (COMPANY PLT) ON THE JUMP SEAT AND AFTER FLYING BY THE TWR HE LOOKED THROUGH THE VIEWPORT IN THE FLOOR AND CONFIRMED THE GEAR WAS FULLY EXTENDED. HE ALSO HELPED FIND AND PULL THE AURAL WARNING CIRCUIT BREAKER. WE LANDED UNEVENTFULLY. THE PROBLEM TURNED OUT TO BE PROXIMITY SWITCH LINKAGE NOT POSITIONING CORRECTLY. WE FOUND THREE PREVIOUS WRITE UPS IN THE LOG BOOK AND THE NON-COMPANY MECHANIC AT MCI SAID OUR COMPANY TOLD HIM THIS WAS THE SEVENTH TIME THIS HAD HAPPENED. TWO OBSERVATIONS: 1) IT SHOULDN'T TAKE SEVEN TIMES TO FIX A SIMPLE PROBLEM LIKE THIS. AIRPLANES HAVE CRASHED IN THE PAST DUE TO SIMILAR PROBLEMS. 2) THE OBSERVER; WHO NORMALLY ISN'T THERE; WAS A BIG HELP AND ALLOWED BOTH PILOTS TO STAY IN THEIR SEATS DURING THIS HIGH WORK LOAD PERIOD.