ACR PLT CRITICAL OF EXCESSIVE GPWS ALARMS OVER MOUNTAINOUS TERRAIN WHILE ON APCH.

Narrative

WHILE APCHING TRI FROM THE E; WE WERE VECTORED ACROSS HOLSTON MOUNTAIN AT 5400 FT MSL IN DAY VMC CONDITIONS. JUST AS WE CROSSED OVER THE PEAK OF THE MOUNTAINS BELOW US WE RECEIVED A GPWS 'TERRAIN' WARNING. THE WARNING CONTINUED AFTER WE PASSED THE MOUNTAIN AND ACHIEVED A RADIO ALT OF GREATER THAN 2500 FT AGL. WE STOPPED THE WARNING EVENTUALLY BY PRESSING THE RADIO ALTIMETER TEST SWITCH. THE UNDERLYING TERRAIN WAS CLRLY IN SIGHT AT ALL TIMES AND AN EVASIVE CLB MANEUVER WAS NOT NECESSARY. I HAVE RECEIVED MANY UNNECESSARY GPWS WARNINGS IN THE TRI AREA; ALL OF WHICH HAVE OCCURRED WHILE UNDER RADAR VECTORS FOR A VISUAL OR INST APCH. THE MINIMUM VECTORING ALTS IN THE AREA ARE OBVIOUSLY TOO LOW AND SHOULD BE RAISED IMMEDIATELY. I DO NOT CONSIDER THESE TO BE 'FALSE' GPWS TERRAIN WARNINGS BECAUSE THE SYS APPEARS TO BE FUNCTIONING AS INTENDED. THE ATC VECTORING ALTS SIMPLY BRING THE ACFT TOO CLOSE TO RAPIDLY CHANGING TERRAIN. EVERY TIME A PLT RECEIVES AN UNNECESSARY GPWS WARNING HIS CONFIDENCE IN THE SYS IS UNDERMINED; MAKING HIM LESS LIKELY TO RESPOND PROMPTLY AND PROPERLY IN THE CASE OF A VALID WARNING. WE WILL CONTINUE TO EXPERIENCE CFIT ACCIDENTS UNTIL UNNECESSARY GPWS WARNINGS ARE ELIMINATED AND PLTS ARE PROVIDED WITH GPWS TRAINING IN THE SIMULATOR. I HAVE SPOKE TO COMPANY AND UNION SAFETY OFFICIALS ABOUT THE PROBS AT TRI AND THEY HAVE APPARENTLY BEEN UNABLE TO DO ANYTHING ABOUT IT. PERHAPS YOU (AT NASA) SHOULD CONTACT THE TRI AUTHORITIES AND EXPRESS YOUR CONCERN.