B737 CREW RPTS GPWS WARNING DURING RNAV APCH TO RWY 8 AT MDPP.

Narrative

DURING RNAV/GPS APCH TO RWY 8 AT POP/MDPP IN VISUAL MET CONDITIONS A PARTIAL TERRAIN AUDIO WAS HEARD WITH PULL UP DISPLAYED ON BOTH PFDS. EVENT OCCURRED IN VICINITY OF KELSO AT APPROX 1800 RA AND 2900 BARO WITH LOCAL ALTIMTER 30.01. PRIOR TO WARNING ALL PARAMETERS APPEARED NORMAL; TRACKING LNAV; RNP.3; ON VNAV PATH; AUTOPLT ENGAGED; ACFT CONFIGURED WITH NO OTHER ALERTS OR WARNINGS. APCH ABANDONED AND CONTINUED AS VISUAL APCH TO LNDG. AT THIS POINT I BELIEVE THE APCH WAS BEING CONDUCTED PROPERLY AND THERE MAY BE AN ANOMALY IN THE DATABASE OR APCH DESIGN WHICH CAUSED THE WARNING. PRECIPITOUS TERRAIN UNDERLYING THE APCH DID NOT APPEAR TO BE A THREAT.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT THE GPWS WARNING WAS VERY BRIEF; LASTING LESS THAN A SECOND WITH NO PULL UP COMMANDS. THE ACFT WAS IN A STEADY DESCENT AS IT PASSED OVER KELSO AND THE RIDGE THAT PROBABLY CAUSED THE WARNING WAS CLEARLY VISIBLE. THE RPTR SENT IN THE RPT TO CAUTION OTHERS THAT THEY MAY RECEIVE AN UNWARRANTED GPWS WARNING PASSING KELSO.