AN MD11 ON APCH AT 3600 FT RECEIVED A GPWS 'TERRAIN; TERRAIN' WARNING AND INITIATED EVASIVE ACTION TO 5500 FT. CREW SUSPECTED A FALSE GPWS WARNING DUE TO TERRAIN AT POINT OF WARNING ONLY 2000 FT.

Report 1 | Narrative: BEING VECTORED INBOUND TO PDX FOR ILS RWY 10R; DSNDING FROM 5000 FT MSL DIRECT TO 3500 FT MSL SLOWING FROM 230 KTS DIRECT TO 210 KTS WITH SLATS AND SPD BRAKES DEPLOYED. AT 3650 FT RECEIVED 'TERRAIN; TERRAIN' GPWS ALERT; INITIATED STANDARD RECOVERY TECHNIQUE TO APPROX 5500 FT MSL. AWARE OF ONLY 2000 FT TERRAIN IN AREA; WITHIN 4 MI OF INTERCEPTING LOC COURSE INBOUND; NORMAL VECTORING ALT FOR THIS AREA; SUSPECT EQUIP MALFUNCTION.

Report 1 | Synopsis: AN MD11 ON APCH AT 3600 FT RECEIVED A GPWS 'TERRAIN; TERRAIN' WARNING AND INITIATED EVASIVE ACTION TO 5500 FT. CREW SUSPECTED A FALSE GPWS WARNING DUE TO TERRAIN AT POINT OF WARNING ONLY 2000 FT.