B757 FLT CREW DESCENDED BELOW GS ON A VISUAL APCH; TRIGGERING A LOW ALT WARNING FROM ATC.

Narrative

DANGEROUS VISUAL APCH; ACFT WAS ROUGHLY 700 FT LOW XING THE FAF FOR RWY 26R AT ATL. GOT A LOW ALT WARNING FROM ATC. CLBED SLIGHTLY; INTERCEPTED GS; AND CONTINUED APCH; MEETING ALL STABILIZED APCH GATES TO A NORMAL LNDG. THAT'S WHAT HAPPENED; THE STORY IS HOW IT HAPPENED. FLT WAS A RED-EYE AND HAD BEEN NORMAL IN EVERY RESPECT UNTIL DSNDING INTO ATLANTA. MY EXPERIENCE HAS BEEN THAT ATL APCH TENDS TO 'SLAM-DUNK' (HIGH AND FAST STRUGGLING TO GET DOWN AND SLOW DOWN; EVEN IN THE FINAL APCH PHASE) THE EARLY ARRIVING RED-EYE FLTS. I REALLY HATE TO BE 'SLAM-DUNKED;' SO I WAS QUITE CONCERNED AND EXPECTING IT. CTR HAD US KEEP OUR SPD HIGH ON THE INITIAL DSCNT; WHICH WAS CONTINUED BY APCH CTL. APCH ALSO GAVE US A VECTOR TO 'CUT ACROSS' TO FINAL; RATHER THAN THE USUAL DOWNWIND. I REALLY FELT A SLAM-DUNK DEVELOPING; SO I USED MAX SPD BRAKES TO MAKE SURE I GOT AS LOW AS POSSIBLE AS FAST AS POSSIBLE; AND FLEW ABSOLUTELY NO FASTER THAN THE ASSIGNED SPDS. THEN; TURNING DOGLEG TO FINAL AT 3500 FT MSL MY FO REALIZED WE HAD NOT DONE THE 'APCH CHKLIST' (SHOULD HAVE BEEN DONE AT AROUND 10000 FT AFE). THIS MEANT I HAD NOT WARNED THE FLT ATTENDANTS THAT LNDG WAS IMMINENT; SO I IMMEDIATELY REACHED UP AND SIGNALED THE FLT ATTENDANTS; WHILE TURNING TO FINAL AND SLOWING TO 160 KTS AS REQUESTED. WE QUICKLY DID THE CHKLIST; THEN I TOLD THE FO TO CALL THE FLT ATTENDANTS ON THE INTERPHONE AND TELL THEM THAT I HAD SCREWED UP AND TO SIT DOWN DOUBLE QUICK. I WOULD REALLY HATE TO HAVE A FLT ATTENDANT INJURED BECAUSE I FORGOT TO SIGNAL. AT THIS POINT I REALIZED THAT THE AUTOFLT SYS (AUTOPLT WAS ON) HAD CAPTURED 3500 FT AND WAS GOING ABOVE THE GS WITHOUT CAPTURING THE GS. I DIALED THE ALT DOWN TO 1700 FT (REALLY JUST SOMETHING LOWER TO ALLOW US TO DSND ON AUTOPLT TO THE GS). I JUST SPUN IT. I SELECTED FLT LEVEL CHANGE; CHKED THAT APCH MODE WAS ARMED; TOLD THE FO TO LOWER THE GEAR AND CALLED FOR FLAP EXTENSION TO 25 DEGS; WHILE DIALING BACK THE SPD TO FINAL APCH SPD. XING THE FAF; APCH (MAYBE IT WAS TWR; I'M NOT SURE) CALLED OUT A LOW ALT WARNING ALERT FOR US. SURE ENOUGH WE WERE AT ABOUT 1800-1900 FT; WELL BELOW THE GS. I CLICKED OFF THE AUTOPLT; CLBED SLIGHTLY; INTERCEPTED THE GS FROM BELOW; AND CONTINUED THE APCH. WE DID ACTUALLY COMPLETE ALL CHKLISTS AND MET ALL OF THE STABILIZED APCH GATES. LNDG WAS NORMAL. LATER; AT THE GATE; I SAT IN THE COCKPIT THINKING ABOUT WHAT HAD HAPPENED AND REVIEWED IT ALL IN MY 'MIND'S EYE.' I WAS HORRIFIED TO REALIZE THAT I HAD NEVER BEEN ABOVE THE GS (I CAN STILL SEE THE ADI PICTURE VERY CLRLY IN MY HEAD). THE LEVELOFF AT 3500 FT WAS FINE AND WE WOULD HAVE VERY SOON CAPTURED THE GS NORMALLY FROM BELOW. INSTEAD; I INTERVENED DSNDING IN FLT LEVEL CHANGE. THE SYS NEVER GOT TO THE GS; SO WE NEVER CAPTURED IT. I WAS EXPECTING A PROB; AND I SAW WHAT I EXPECTED. I THINK I WAS SO PREOCCUPIED WITH A POSSIBLE SLAM-DUNK THAT I LET EVERYTHING ELSE SLIDE (FORGOT TO DO THE APCH CHKLIST). DOING THE APCH CHK; AND ORDERING MY FO TO TALK TO THE FLT ATTENDANTS TOOK HIM OUT OF THE LOOP. WE WERE VERY RAPIDLY RUNNING A CHKLIST (SHORT ONE; LUCKILY); TURNING TO FINAL; SLOWING DOWN; CONFIGURING TO LAND; SWITCHING TO TWR FREQ; AND TRYING TO CAPTURE THE GS. MY XCHK OBVIOUSLY BROKE DOWN; AND I FORCED MY FO OUT OF THE LOOP; SO HE DIDN'T CATCH THE LOW ALT EITHER. THE AUTOFLT SYS DID EXACTLY WHAT I TOLD IT TO DO. THERE WAS NO MALFUNCTION OTHER THAN MY OWN. I SAW WHAT I EXPECTED TO SEE; RATHER THAN WHAT WAS REALLY TRUE. I ALSO LET MY CONCERN FOR THE FLT ATTENDANTS INTERVENE IN THE AVIATE; NAV; COM; HIERARCHY. BAD; REALLY BAD. WAS FATIGUE A FACTOR? WELL; IT WAS EARLY MORNING; BUT I DIDN'T FEEL BAD AT ALL. I HAD NAPPED WELL ON THE LAYOVER AND WAS WELL RESTED FOR THE FLT. SO IT WAS BACKSIDE OF THE CLOCK; AND A PERIOD OF CIRCADIAN LOW; BUT I CAN'T REALLY SAY THAT FATIGUE WAS ANY MORE THAN A MINOR FACTOR; IF THAT. MY FO WAS FAIRLY NEW; BUT HIS PERFORMANCE AND ATTITUDE HAD BEEN EXCELLENT FOR THE ENTIRE TRIP. HE IS A VERY GOOD PLT. HE KEPT UP WITH ALL I ASKED OF HIM THERE ON FINAL; EXCEPT THAT HIS XCHK BROKE DOWN AS WELL. HOWEVER; I ORDERED HIM TO CALL THE FLT ATTENDANTS ON THE INTERPHONE; SO I CAN'T BLAME HIM FOR A POOR XCHK. I GUESS HE FORGOT THE APCH CHKLIST TOO; BUT IT IS MY RESPONSIBILITY AS PF AND AS CAPT TO MAKE SURE ALL CHKLISTS ARE COMPLETED. I FEEL LUCKY TO HAVE HAD THIS PARTICULAR FO. AFTER WE STARTED CORRECTING MY MISTAKE HE WAS RIGHT BACK IN THE LOOP AND HELPED GET EVERYTHING BACK IN ORDER; AND TO GET ALL SUBSEQUENT ACTIONS COMPLETED. I REALLY APPRECIATE THE ATC LOW ALT WARNING. IT FORCED ME TO ASSESS AND CORRECT THE SITUATION. HOWEVER; IT PROBABLY DIDN'T PREVENT US FROM GOING ANY LOWER; BECAUSE I THINK THE AUTOPLT ACTUALLY STARTED TO CAPTURE 1700 FT BEFORE I DISCONNECTED IT AND CLBED. THERE WAS NO GPWS WARNING.