A TRANSPORT CATEGORY ACFT FLT CREW REPORTS AN EGPWS WARNING ON SHORT FINAL TO TAPA; WITH NO CORRESPONDING TERRAIN/OBSTACLES VISIBLE OR DISPLAYED ON THE ACFT'S PFD.

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DURING FINAL APCH TO LNDG IN TAPA; RWY 07; WE RECEIVED AN EGPWS WARNING FOR AN OBSTACLE. CONDITIONS WERE DAY VFR AND WE WERE WELL CLEAR OF ALL TERRAIN AND OBSTACLES. THE ACFT WAS APPROX 4 MI FROM THE END OF THE RWY AT APPROX 1200 FT AGL; ON THE RWY CTRLINE AND ON THE CORRECT GLIDE PATH (2 WHITE 2 RED PAPI). THERE WERE NO CHARTED OBSTACLES IN THE IMMEDIATE PATH AND THERE WERE NO RED OR YELLOW OBSTACLES DISPLAYED ON THE ND IN THE TERRAIN MODE. I HAVE SPOKEN TO OTHER PLTS WHO HAVE EXPERIENCED THE EXACT SAME THING RECENTLY GOING INTO TAPA. I SUSPECT THAT THERE IS SOMETHING CORRUPT IN THE EGPWS DATABASE AS THIS SEEMS TO BE HAPPENING TO TOO MANY ACFT THAT ARE ESTABLISHED WITHIN PARAMETERS ON FINAL APCH TO TAPA RWY 07. THERE ARE NO NOTES ON ANY OF THE COMPANY OR COMMERCIAL CHART PAGES FOR TAPA STATING THAT APCH PROCS DIFFER FROM STANDARD ICAO PROCS DUE TO OBSTACLE CLRNC CONCERNS. WOULDN'T THERE BE IF YOU WEREN'T SUPPOSED TO FOLLOW THE PAPI'S INSTALLED FOR THAT RWY?SUPPLEMENTAL INFO FROM ACN 684450: RECEIVED TERRAIN AND OBSTACLE ALERTS FROM EGPWS ON FINAL. BECAUSE I WAS BRIEFED OTHER CREWS HAD RECEIVED THIS TERRAIN AND OR OBSTACLE WARNINGS ON FINAL TO RWY 07 AT TAPA AND I WAS POSITIONED APPROPRIATELY ON FINAL AND COULD CLEAR THE APCH CORRIDOR VISUALLY; I CONTINUED. EVERY CREW I HAVE TALKED TO THAT HAS FLOWN INTO TAPA RECENTLY REPORTS SIMILAR ALERTS; WARNINGS; OR CAUTIONS ON FINAL TO TAPA RWY 07. NOTHING RED SHOWED ON EGPWS DISPLAY CONCURRENT WITH WARNINGS.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT HE DOES NOT KNOW THE SOURCE OF THE WARNINGS AND DOES NOT RULE OUT A SPURIOUS ANNUNCIATION BECAUSE HE CANNOT SEE AN OBSTACLE IN THAT AREA. BECAUSE HIS FO HAD THIS EXPERIENCE BEFORE AND DID NOT REMEMBER A PFD WARNING; THEY WERE BOTH ANTICIPATING A RED OR AMBER PFD WARNING BUT IN THIS EVENT; THE PFD ANNUNCIATION DID NOT OCCUR COINCIDENTAL WITH THE AURAL ALERT.