CRJ900 FO DESCENDS EARLY ON THE VOR RWY 8 TO PNS THINKING NUN IS PNS. PNS TOWER CALLS LOW ALTITUDE ALERT AT THE SAME TIME THE CAPT DISCOVERS THE EARLY DESCENT AND THE FO CLIMBS BACK TO PROPER ALTITUDE.

Narrative

WE WERE BEING VECTORED FROM THE NE TO THE PNS (PENSACOLA REGIONAL) VOR RWY 8 APCH. THE APCH CTLR CLRED US FOR THE APCH AND TOLD US TO MAINTAIN 2000 FT UNTIL ESTABLISHED ON THE APCH AND HANDED US OFF TO THE PNS CTLR. I REMEMBER THE CAPT POINTING OUT AN ARPT OFF TO OUR L (PENSACOLA COASTAL) AND MAKING THE COMMENT THE HE WONDERED HOW MANY PLTS HAD MISTAKEN IT FOR PNS. AN AFTER THE FACT REVIEW REVEALED THAT HE WAS REFERRING TO SAUFLEY ARPT. I THOUGHT HE WAS REFERRING TO PENSACOLA COASTAL. WE INTERCEPTED THE LOC OUTSIDE OF THE NUN VOR AND HAD ALREADY BROKEN OUT OF THE BROKEN CLOUD LAYER WHICH WAS HIGHER THAN RPTED; ALTHOUGH THE VISIBILITY WAS LIMITED BY HAZE. IRONICALLY BECAUSE OF THE HAZY SKY CONDITIONS I DID NOT CLRLY SEE PNS IN THE DISTANCE AND MISTOOK SAUFLEY ARPT AS PNS. OUR AUTOPLT HAD CAPTURED THE 2000 FT THAT WE HAD BEEN TOLD TO MAINTAIN AND SO THE CAPT AS PER PROC AND MY REQUEST SET THE MDA OF 800 FT INTO THE ALT SELECTOR. I COULD SEE SAUFLEY AND SINCE I THOUGHT IT WAS PNS I THOUGHT I WAS HIGH ON THE APCH AND DISCONNECTED THE AUTOPLT TO DSND VISUALLY TO LAND. AS I WAS DSNDING TO THE 800 FT ALT THAT THE CAPT HAD SELECTED FOR ME; PNS BECAME MORE VISIBLE. I XCHKED MY APCH PLATE AND REALIZED THAT I WAS STILL OUTSIDE OF THE FAF AND THAT THE ARPT I WAS DSNDING TO WAS NOT THE INTENDED PNS BUT SAUFLEY. AFTER REALIZING MY MISTAKE I IMMEDIATELY STARTED TO ASCEND BACK TO THE 2000 FT LEVEL. AT ABOUT THE SAME TIME THE PNS TWR CTLR GOT A LOW ALT ALERT AND QUERIED US. AT THAT POINT WE WERE FLYING OVER SAUFLEY ARPT AND THE FAF AT NUN. I ATTRIBUTE THE INCIDENT TO THE HAZY CONDITIONS AND 3 ARPTS IN RELATIVELY CLOSE PROX TO EACH OTHER. I SHOULDN'T HAVE STARTED MY DSCNT TO THE MDA UNTIL AFTER VERIFYING AND XCHKING THAT WE WERE PAST THE FAF TO PNS. THE ILLUSION WAS THAT WE WERE VERY HIGH ON A VISUAL APCH TO THE ARPT THAT I THOUGHT WAS PNS BUT IN REALITY WAS SAUFLEY. AS A RESULT I CONSIDERED MYSELF VISUALLY ESTABLISHED TO MAKE A LNDG. IN REALITY; I WAS VERY LOW FOR A VOR APCH TO PNS AND HENCE A LOW ALT ALERT FROM THE PNS TWR CTLR. I FELL PREY TO THE OPTICAL ILLUSIONS OF HAZY CONDITIONS. I REVIEWED THE CHARTS AND DID NOT FIND ANY NOTES OR WARNINGS THAT INDICATED THAT THERE ARE OTHER ARPTS IN CLOSE PROX TO PNS AND THAT THESE ARPTS COULD BE MISTAKEN FOR PNS IN LOW VISIBILITY OR HAZY CONDITIONS. SUPPLEMENTAL INFO FROM ACN 758145: WHILE FLYING THE VOR RWY 8 APCH TO PENSACOLA; FL; WE DSNDED BELOW 2000 FT MSL WHILE STILL OUTSIDE THE FAF (NUN VOR) I; THE PNF; MADE A REMARK TO MY FO TO THE EFFECT THAT SAUFLEY FIELD COULD BE MISTAKEN FOR PENSACOLA. IRONICALLY; HE DID JUST THAT AND BEGAN HIS DSCNT WHILE ABOUT 1 NM OUTSIDE THE VOR. WE BOTH REALIZED THE MISTAKE AND INITIATED A PROMPT CORRECTION; AT THE SAME TIME RECEIVING A 'LOW ALT' ALERT FROM THE TWR. FURTHER ADDING TO THE CONFUSION WAS THAT I HAD PNS IN SIGHT; AND MOMENTARILY THOUGHT WE WERE DSNDING TO LAND. I HAVE NOTICED AN APPARENT WEAKNESS IN SOME OF OUR NEWER PLTS WHEN IT COMES TO NON-PRECISION APCHS; PRIMARILY THE VOR AND LOC APCHS WE OCCASIONALLY ENCOUNTER. MY FO AND I DISCUSSED IT AT LENGTH AFTERWARDS; AND THERE WAS AN AREA OF CONFUSION REGARDING WHEN WE WERE PERMITTED TO DSND BELOW MDA; OR ANY ALT ON A GIVEN SEGMENT OF (IN THE CASE) A VOR APCH. MY RESPONSE WAS 'NEVER;' WITH A SLIGHT PAUSE; THEN EXPLAINING THE EXCEPTION OF BEING CLRED FOR A VISUAL APCH OR BEING AT MDA WITH THE RWY; ETC; IN SIGHT; MAKING A DSCNT FOR A NORMAL LNDG; EXPLAINING THE VDP; AND SO FORTH. I INSTRUCTED MY FO THAT WHEN CLRED FOR AN INST APCH; YOU FLY THAT APCH UNTIL CLRED OTHERWISE; TO SUM IT UP. IT'S ONLY A VISUAL APCH WHEN YOU ARE CLRED FOR IT! LOOKING BACK; I HAD LET MY GUARD DOWN DURING THAT MOMENT OF THE APCH; SETTING RADIOS AND THE LIKE. MY FO AND I HAD FLOWN SEVERAL TRIPS TOGETHER; AND HE IS A VERY COMPETENT PLT.