B727-100 FO DSNDED EARLY PRIOR TO THE ILS OM RESULTING IN APCH CTLR INTERVENTION AND INSTRUCTING FLC TO CLB BACK APCH ALT.

Narrative

AFTER A LONG; DIFFICULT NIGHT OF FLYING AND WX PROBS WE WERE ON APCH INTO MEM WITH ++RA AND TSTMS IN AREA. WE HAD BEEN TOLD TO EXPECT THE ILS TO RWY 18L AND HAD BRIEFED IT. ABOUT 10 MI FROM ARPT; WE WERE TOLD TO NOW EXPECT THE RWY 9 ILS. WE SCRAMBLED TO GET OUT; BRIEF AND SET UP FOR THE APCH. WHILE DOING THIS; THE FO WHO WAS THE PF; HAD EXTENDED THE SPD BRAKES TO LOSE THE EXTRA ALT WE NOW HAD FOR THE RWY 9 APCH AS WELL AS SLOW DOWN. AFTER ALL WAS SET UP; WE WERE GIVEN A VECTOR TO INTERCEPT THE RWY 9 ILS AND TO MAINTAIN 2000 FT UNTIL ESTABLISHED AND THEN CLRED FOR THE APCH. I WAS STILL BUSY TRYING TO GET A STRONG IDENT FROM THE LOM WHEN I NOTED THE FO HAD INTERCEPTED THE LOC AND WAS CONTINUING HIS DSCNT FROM 2000 FT. BOTH MY GS INDICATORS (FLT DIRECTOR AND HSI) SHOWED NO GS NEEDLES AT THIS POINT; BUT OUT OF THE CORNER OF MY EYE I NOTICED THE RADAR ALTIMETER NEEDLE START TO JUMP TOWARDS 1500 FT. JUST AS I REALIZED (WITH A NOW STRONG IDENT AND NEEDLE) THAT WE HAD NOT YET PASSED ELVIS LOM AND WE WERE NOW BELOW THE XING ALT OF 1415 FT AND WERE ABOUT TO TELL THE FO THAT WE WERE BELOW THE GS; APCH CALLED AND SAID WE WERE LOW AND TO CLB BACK TO 2000 FT. APPARENTLY WE WERE JUST SHORT OF XING BUDEE (IAF) WHICH IS TO BE CROSSED AT 2000 FT BEFORE DSCNT TO THE LOM XING ALT ABOUT .9 MI LATER. WE CLBED UP TOWARDS 2000 FT AND INTERCEPTED THE GS; FOLLOWED BY AN UNEVENTFUL LNDG. THE FO CLAIMS HIS FLT DIRECTOR (RAW DATA) GS NEEDLE WAS INDICATING HE WAS HIGH THE ENTIRE TIME UP TO 'I' AND APCH QUESTIONED IT. HE APPARENTLY DID NOT LOOK AT THE HSI GS INDICATOR SINCE HE COULD NOT ANSWER MY QUESTION AS TO WHAT IT SHOWED. HE SAID HIS FLT DIRECTOR NEEDLE (RAW) SUDDENLY SNAPPED FROM INDICATING FULL DOWN TO FULL UP SHOWING US LOW. HE HAD NOT BEEN XCHKING WITH OTHER DATA AND XING ALTS AND I INITIALLY HAD NOT MONITORED HIM ENOUGH WHILE TRYING TO GET EVERYTHING SET UP FOR THE LAST MIN APCH CHANGE. CONCLUSION AND LESSONS: 1) XCHK EVERYTHING. 2) DO NOT LET ATC PUT YOU INTO A LAST MIN RUSHED SIT. 3) AS CAPT; I MUST STRIVE TO MONITOR MY CREW MORE CLOSELY WITH THE BASICS LIKE FLYING THE ACFT AND SITUATIONAL AWARENESS.