PLT DEPARTED UNCTLED ARPT WITHOUT IFR CLRNC.

Narrative

I WAS THE PF ON A TRIP FROM GAI; MD; TO TDZ; OH; WITH THE OWNER OF THE AIRPLANE WORKING THE RADIO. WHILE TAXIING OUT FOR DEP; I SAW A NUMBER OF OTHER ACFT PREPARING TO DEPART. I DECIDED IT WOULD BE BETTER TO DEPART VFR TO PICK UP MY IFR CLRNC IN THE AIR THEN TO CAUSE A LOG JAM AT GAI IF I HAD A PROB GETTING IT ON THE REMOTE FREQ; AS HAPPENS FREQUENTLY AT TDZ; WHERE I AM BASED. I DECIDED TO STAY BELOW 3000 FT UNTIL REACHING A RAILROAD TRACK JUST S OF FREDERICK; MD; TO STAY OUT OF OVERLYING CLASS B AIRSPACE. AS I DEPARTED; WE GAVE BWI APCH A CALL FOR OUR CLRNC; AND WERE IMMEDIATELY TOLD THAT WE SHOULD HAVE GOTTEN IT ON THE REMOTE FREQ. THE CTLR EXPLAINED THAT IT WAS BETTER TO DO IT THAT WAY. WHILE WAITING FOR THE CLRNC; THE PANEL-MOUNTED GPS SHOWED THAT WE WERE CLRING THE OVERLYING CLASS B SHELF. I ALSO COULD SE THAT WE WERE CLOSE TO THE TRACKS; SO I CONTINUED MY CLB ABOVE 3000 FT. AS WE APCHED 5000 FT; THE AIRPLANE'S OWNER POINTED TO AN AIRLINER APCHING FROM THE R. AT THIS TIME THE CTLR STATED THAT WE WERE 'IN DULLES' AIRSPACE; IN THE APCH CORRIDOR.' THE GPS STILL SHOWED CLR; AND BY XCHKING THE CHART WITH WHAT I SAW; IT LOOKED AS IF WE WERE N OF CLASS B. I'M NOT SURE IF I WAS IN THE AIRSPACE; OR IF THE CTLR HAD MEANT THAT I HAD FLOWN ACROSS THE DESIRED APCH COURSE INTO DULLES. SINCE HE WAS BUSY; I DIDN'T PURSUE IT. HE THEN TOLD US TO CONTACT DULLES APCH. THE NEW CTLR DID NOT MENTION THE INCIDENT; AND GAVE US OUR IFR CLRNC. IT BOTHERED ME FOR THE REST OF THE FLT; AND UPON LNDG; I DISCUSSED THE INCIDENT WITH THE CHIEF PLT OF MY COMPANY'S CHARTER DEPT. HE TOLD ME THAT IN A HIGH DENSITY TFC AREA TO NEVER TRY TO OBTAIN A CLRNC IN THE AIR; AND IF I DID; TO STAY ONLY ABOUT 1000 FT AGL WHEN DOING SO. HE STRONGLY ENCOURAGED ME TO USE REMOTE FREQS OR LANDLINES TO OBTAIN A CLRNC IN SUCH AN AREA IN THE FUTURE. THESE ARE PRACTICES THAT I INTEND TO USE. THE TOLEDO AREA IS NOT A HIGH DENSITY AREA; AND IT IS USUALLY EASY TO GET AN IFR CLRNC IN THE AIR. THIS WAS MY FIRST FLT TO THE ATLANTIC COAST AREA; AND I FEEL THAT I WAS A LITTLE OVERWHELMED. FINALLY; I FEEL THAT I WAS TOO RELIANT ON THE GPS MAP; AND SHOULD HAVE KEPT BETTER TRACK OF MY POS USING THE VFR SECTIONAL. THIS WOULD HAVE ELIMINATED ANY CONFUSION.