A PVT PLT FLYING LIGHT TWIN TO PDK ENTERED FTY AIRSPACE WITHOUT PROPER AUTH.

Narrative

APCHING PDK FROM W; THERE IS CONFUSION ON AIRSPACE CTL WITH REGARD TO FTY; MGE (DOBBINS AFRB); ATLANTA; GA. I WAS SPLITTING THE DISTANCE BTWN FTY AND MGE ENRTE TO PDK WHEN I LATER RECEIVED WORD OF POSSIBLE AIRSPACE VIOLATION OF FTY. AFTER DISCUSSING WITH 3 WELL-SEASONED PLTS; THERE WERE 3 DIFFERENT OPINIONS AS TO THE CLASS D REQUIREMENTS. FTY TWR CLAIMS CTL TO 3800 FT (3000 FT AGL) PER FARS. IT HAS BEEN UNDERSTOOD FOR SEVERAL YRS THAT ATL APCH OWNED ANYTHING OVER 3000 FT MSL. A THIRD PROFESSIONAL AIRLINE CAPT SAID THAT THE VFR TERMINAL CHART -- ATLANTA (59TH EDITION) INDICATED THAT FTY CLASS D CEILING WAS 3300 FT. THE WX WAS VFR; 20 MI CAVU; BUT APPARENTLY A HAWKER ON IFR FLT PLAN WAS FORCED TO EXTEND DOWNWIND LEG TO GET AROUND MY COURSE. I SAW THE ACFT AND DETECTED NO THREAT TO SAFETY. I BELIEVE THAT CLARIFICATION; HOWEVER; ON VFR TFC REQUIREMENTS FROM PDK WESTWARD OR APCHING PDK FROM THE W IS IN ORDER. STAYING WITH FTY TWR UNTIL CLR OF THEIR SPACE LEAVES TOO LITTLE TIME TO CONTACT THE CONGESTED PDK TWR AND ASSOCIATED AIR OPS.