AN ACR MD88 FLC STARTED DSCNT TO THE MDA FOR A LOC APCH BEFORE XING THE FINAL APCH FIX. THE CAPT USED AN INAPPROPRIATE TECHNIQUE TO DETERMINE STATION PASSAGE.

Narrative

ON ILS RWY 3 APCH (GS INOP) AT GREER ARPT; AT 2700 FT MSL (PUBLISHED AND ASSIGNED ALT); ABOUT 1 MI PRIOR TO FINAL APCH FIX (GREER OMB); CAPT STATED 'STATION PASSAGE; STARTING TIME.' I BEGAN DSCNT TO MDA (1380 FT MSL). WHEN I LOOKED AT MY NAV DISPLAY; I NOTICED THE ADF NEEDLE POINTING AHEAD OF THE ACFT INDICATING NO STATION PASSAGE. I TOLD THE CAPT THAT MY NEEDLE HAD NOT SWUNG AND WE BOTH BEGAN TO TRY TO FIGURE OUT THE PROB. I THEN REALIZED THAT THE CAPT'S NEEDLE HAD NOT SWUNG EITHER; AND THAT HE BASED STATION PASSAGE ON THE ACARS MAP; IN ERROR. WE WERE ALREADY BELOW 2700 FT. THE NEEDLE THEN SWUNG; AND SHORTLY AFTER WE CAME OUT OF THE CLOUDS AND COULD SEE THAT WE COULD PROCEED TO THE RWY WITH NO POSSIBILITY OF HITTING ANY OBSTRUCTIONS; SO I CONTINUED WITH THE APCH AND LANDED NORMALLY. CONTRIBUTING FACTORS: 1) CAPT'S USE OF FMS MAP AT INAPPROPRIATE TIME. 2) MY RELIANCE ON CAPT'S CALL WITHOUT XCHK. 3) OUR FAILURE TO IMMEDIATELY CLB ON REALIZATION THAT WE WERE BELOW PRESCRIBED ALT. 4) RELIANCE ON A SINGLE NAVAID AT A CRITICAL POINT IN A FLT; SUCH AS THE GREER OM. CORRECTIVE ACTIONS: 1) TRAIN CREWS TO TURN OFF FMS MAP AND USE ONLY APPROPRIATE NAVAIDS FOR THIS TYPE OF APCH. 2) TRAIN CREWS TO ALWAYS XCHK; QUESTION; AND BE SPRING-LOADED FOR MISSED APCH. 3) MINIMIZE ILS DOWN TIME DURING CONSTRUCTION.