GLF3 ON VOR APCH TO SDM DURING NON TWR OPS; LANDS AT TIJUANA; (TIJ) MEXICO.

Narrative

I WAS PIC OF A GULFSTREAM G-III ACFT MAKING THE VOR APCH TO SDM (BROWN MUN). THE WX WAS IFR AND THE TWR WAS CLOSED. I DSNDED TO 1500 FT MSL AND BROKE OUT OF THE CLOUD DECK JUST PRIOR TO REACHING PGY VOR. I ESTIMATE THE VISIBILITY WAS 3 MI IN HAZE. JUST PRIOR TO BREAKING OUT; THE APCH CTLR ADVISED THAT PARACHUTE JUMPERS HAD JUST BEEN DROPPED 1 MI E OF THE FIELD. I WAS CONCENTRATING ON FLYING THE ACFT AND THE COPLT WAS LOOKING FOR THE FIELD AND THE JUMPERS. WHEN HE SPOTTED THE ROTATING BEACON; HE ADVISED APCH CTL AND ME. I CONCURRED. I TURNED L FOR A R DOWNWIND AND BECAUSE THE FIELD WAS ON HIS SIDE OF THE ACFT; TURNED THE CTLS OVER TO HIM. HE FLEW THE DOWNWIND AND BASE LEGS; THEN TURNED THE CTLS BACK TO ME FOR THE LNDG (A PROC WE HAD DONE BEFORE). HE ALSO MADE CALLS ON THE UNICOM FREQ TO ADVISE OUR INTENTIONS. ON LNDG; WE SAW THAT THE RWY WAS LONGER THAN WE HAD EXPECTED AND THERE WERE ACFT ON THE N SIDE OF THE FIELD PARKED AT JETWAYS. IMMEDIATELY; WE KNEW WE HAD NOT ONLY LANDED AT THE WRONG ARPT WITHOUT PERMISSION (THIS FIELD HAD AN OPERATING TWR); WE HAD LANDED IN MEXICO. SCRAMBLING THROUGH OUR APCH PLATES; THE COPLT CAME UP ON THE TWR FREQ OF GENERAL ABELARDO L RODRIQUEZ INTL APT IN TIJUANA; MEXICO. WE TAXIED TO A POS NEAR THE TWR AND WERE MET BY OFFICIALS WHO ADVISED US WE HAD LANDED WITHOUT PERMISSION AND WOULD NEED TO FILL OUT SOME FORMS TO BE ALLOWED TO TAKE OFF AND LAND AT SDM. AFTER FILLING OUT FORMS; PAYING LNDG FEES AND GRATUITIES; WE TOOK OFF WITH AN IFR CLRNC AND SHOT THE GPS APCH TO RWY 8 AT SDM AND LANDED WITHOUT FURTHER INCIDENT. THE TIJUANA TWR OPERATOR TOLD US; OVER THE RADIO; THAT THIS TYPE OF INCIDENT HAPPENS ALMOST EVERY OTHER DAY. THE CUSTOMS OFFICERS AT SDM SAID IT 'HAPPENS ALL THE TIME.' THERE IS NO NOTE ON THE APCH PLATE TO WARN THAT THERE IS A MAJOR ARPT 2 MI S OF SDM. THE PICTORIAL ON THE APCH CHART SHOWS AN ARPT SMALLER THAN SDM. IN FACT; IT IS MUCH LARGER. THE MAIN RWYS AT BOTH ARPTS ARE PARALLEL. AND; THE APCH IS FROM THE N TO THE S; SO THAT A HARD L TURN IS REQUIRED TO LINE UP ON DOWNWIND; BLOCKING BOTH PLTS' ABILITY TO KEEP THE PROPER ARPT IN SIGHT. THE ARPTS ARE WITHIN 2 MI OF EACH OTHER AND THE MEXICAN ARPT IS MUCH BETTER ILLUMINATED.