ACFT EQUIP PROB GPWS FALSE ALERT.

Narrative

WHILE IN A CLBING L TURN TO ASSIGNED HDG 320 DEGS AT 1100 FT AGL; 160 KTS; 1500 FPM CLB; WE GOT A MODE 2 GPWS ALERT OF 'TERRAIN; TERRAIN.' LIT WX AT THE TIME WAS 300 FT OVCST; 3/4 MI FOG. BECAUSE WE WERE IMC; I IMMEDIATELY INITIATED A FIREWALL PWR MAX RECOVERY. THE MODE 2 'TERRAIN; TERRAIN' SOUNDED FOR APPROX 400 FT UNTIL 1500 FT AGL. AT THAT TIME WE TERMINATED THE RECOVERY. DURING THE RECOVERY; AN N2 HIGH ALERT WAS DISPLAYED AND THE N2 INDICATOR TURNED AMBER. THE ALERT TURNED WHITE AFTER THE PWR WAS REDUCED. ALL ENG AND PWR WERE NORMAL; SO I DECIDED TO CONTINUE TO DFW. ALL INDICATIONS WERE ENTERED IN THE LOGBOOK. AFTER RETURNING TO DFW; I CALLED LIT TWR AND SPOKE TO THE SUPVR WHO CONFIRMED THAT THERE WAS NO TERRAIN IN THE AREA THAT WOULD CAUSE THE ALERT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR WAS THE CAPT ON THIS TRIP. HE HAS NEVER SEEN A FALSE GPWS ALERT ON THE FK10 BEFORE. RAIN WAS FALLING AT THE TIME WHICH PROBABLY HAD NOTHING TO DO WITH THE FALSE ALARM. DFW MAINT SAID THAT 'NO FAULT WAS SHOWN IN THE COMPUTER' AND NO MAINT ACTION WAS TAKEN. THE RPTR ADMITS THAT HIS ESCAPE MANEUVER PERFORMANCE WAS COLORED BY THE ACR ACCIDENT AT CALI; COLOMBIA. HE REALIZES THAT THERE IS NO HIGH TERRAIN AT LIT THAT WOULD REQUIRE THIS TYPE MANEUVER. SUPPLEMENTAL INFO FROM ACN 325663: THE HIGHEST TERRAIN ON OUR CHARTS WAS 443 FT. WE FIREWALLED ENGS AND INCREASED RATE OF CLB. WE ASSUMED IT WAS A FALSE WARNING. NEVERTHELESS WE TREATED IT AS THE REAL THING.