AN SMA PLT; IN BUMPY WX; MAY HAVE ENTERED THE BHM ARSA. HE WAS UNABLE TO CONTACT BHM APCH CTL AS THE FREQ LISTED ON THE LATEST SECTIONAL CHART IS WRONG.

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I WAS PROCEEDING VFR BACK FROM PLR TO 3AI. I HAD OBTAINED A PREFLT WX BRIEFING FROM ANNISTON FSS. I WAS TOLD ABOUT A LINE OF TRW AND RAIN SHOWERS THAT WERE N/NE OF MY COURSE. I WAS TRYING TO CIRCUMNAV THIS LINE OF TRW WHEN I MAY HAVE INADVERTENTLY ENTERED THE ARSA WITHOUT ESTABLISHING PRIOR COM. I TRIED THE FREQ LISTED ON THE LATEST ATLANTA SECTIONAL 124.5 BUT COULD NOT ESTABLISH CONTACT WITH BIRMINGHAM APCH. I WAS TRYING TO END RUN A LINE OF FAST MOVING STORMS AND ENCOUNTERED TURB AND WINDSHEAR MAKING IT DIFFICULT TO FLY AND READ THE CHART AT THE SAME TIME. I DSNDED TO REMAIN CLR OF THE ARSA -- BUT I MAY HAVE ENTERED A PORTION INADVERTENTLY -- I WAS BOUNCING AROUND TOO MUCH TO BE SURE I WAS ENTIRELY CLR. WHEN I COULD NOT DIVERT AROUND THIS LINE; I CONTACTED BIRMINGHAM TWR ON 119.9 AND DIVERTED TO BIRMINGHAM. AFTER LNDG I DISCOVERED BIRMINGHAM APCH FREQ WAS CHANGED TO 118.25. THIS CHANGE IS NOT REFLECTED ON THE NEW ATLANTA SECTIONAL CHARTS ON THE LATEST ARPT FACILITY DIRECTORY. I HAVE FILED A SAFETY IMPROVEMENT RPT WITH THE FAA AND AM NOTIFYING NOS. THIS COULD BE A HAZARDOUS SITUATION THAT COULD BE AVOIDED BY MONITORING THE OLD FREQ AND INFORMING PLTS OF FREQ CHANGE.