CAPT OF A B757 COMPLAINS ABOUT THE LNDG GEAR WARNING SYS IN THAT IT DOES NOT SOUND WHEN THE WING FLAPS ARE GOING DOWN TO THE LNDG SETTING. HE WAS SURPRISED WHEN HE NOTICED THE GEAR NOT DOWN AFTER THE FLAPS WERE PUT TO THE LNDG SETTING.

Narrative

I WAS FLYING CAPT ON A B757 AND TURNED ONTO THE RWY 30L LDA APCH AFTER HAVING BEEN TOLD WE WERE ON A VECTOR FOR A VISUAL. WE WERE HELD AT 6000 FT PAST BBUCK INTXN AND ASKED TO KEEP A B737 IN SIGHT (HE WAS MAKING A VISUAL TO THE R PARALLEL RWY). WE HAD TO ASK FOR LOWER AND THEN STEPPED DOWN AND SLOWED TO 190 KTS. BECAUSE WE HAD TO SLOW AND GET DOWN; I USED SPD BRAKES AND THEN EXTENDED FLAPS ON SCHEDULE TO 20 DEGS. WE WERE THEN CLRED TO EXECUTE THE VISUAL TO RWY 30L. I WAS RETUNING THE ILS; AND CALLED FOR FLAPS 25 DEGS. I BELIEVED I HAD ASKED FOR THE GEAR DOWN. I WAS ALSO WATCHING THE TFC ON THE R RWY. I INADVERTENTLY LEFT THE SPD BRAKES EXTENDED AND GOT AN EICAS WARNING AND SIMULTANEOUSLY REALIZED I HAD LNDG FLAPS AND THE GEAR STILL UP. I IMMEDIATELY RETRACTED SPD BRAKES AND CALLED FOR THE GEAR. THE FO WAS A CAPT/CHK AIRMAN AND HE TOO WAS ENGROSSED IN CALLING THE TWR; WATCHING THE B737 AND HE LOWERED THE FLAPS TO LNDG BEFORE THE GEAR WAS DOWN. WE WERE SAFELY STABILIZED AND CONFIGURED BY 800 FT AND COMPLETED THE CHKLISTS; FOLLOWED BY AN UNEVENTFUL LNDG. THE PREOCCUPATION WITH THE TFC AND APCH CHANGE; AND LATE DSCNT ALL ACTED AS DISTRS. I BELIEVE THE CLOSE PARALLELS TO STL RWY 30L/R ARE FULL OF THESE POSSIBLE TRAPS AND ATC SHOULD MINIMIZE LAST MIN CHANGES. WE HAD 2 COCKPIT JUMP SEAT RIDING PLTS WHO ALSO WERE WATCHING FOR TFC. I WILL NEVER AGAIN GET SO PREOCCUPIED. RECOMMENDATION: BOEING SHOULD REVISE LOGIC SO GEAR WARNING SOUNDS IMMEDIATELY UPON SELECTING LNDG FLAPS WITH GEAR HANDLE UP OR NEUTRAL REGARDLESS OF ALT OR AIRSPD. THE MCDONNELL-DOUGLAS MD80 LOGIC WOULD HAVE SOUNDED AS SOON AS THE FLAP HANDLE WAS MOVED TOWARD LNDG FLAPS WITH THE GEAR HANDLE UP.