Narrative:

The WX was originally forecast to be marginal VFR throughout new jersey this date. However, the WX made a very abrupt turn for the worse in mins. Severe WX was erupting all over south jersey surprising everyone. I had left wilmington, de, eastbound VFR with several small thunderstorm cells showing on my radar to the east and southeast. Suddenly, the screen lit up with severe WX in all areas. I was at that time following the new jersey turnpike and also using LORAN and VOR navigation. Visibility got very low and I circled VFR where I thought I was still clear of philadelphia class B airspace. I contacted the approach controller, advised him of my conditions and asked for IFR routing back to wilmington. At that time he advised me that I had penetrated philadelphia class B and was 4.8 NM south of philadelphia. I told him I was avoiding heavy WX and inadvertently entered, unknown to me. He then cleared me back to wilmington, IFR. He also stated my intrusion was no big deal and that everyone was surprised by the instant WX change going on. My concern was keeping myself, passenger, and aircraft safe at this time and obtaining an IFR clearance to avoid an accident, etc.

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Original NASA ASRS Text

Title: CAPT OF AN SMT HELI INADVERTENTLY PENETRATED CLASS B AIRSPACE DUE TO DETERIORATING WX CONDITIONS.

Narrative: THE WX WAS ORIGINALLY FORECAST TO BE MARGINAL VFR THROUGHOUT NEW JERSEY THIS DATE. HOWEVER, THE WX MADE A VERY ABRUPT TURN FOR THE WORSE IN MINS. SEVERE WX WAS ERUPTING ALL OVER SOUTH JERSEY SURPRISING EVERYONE. I HAD LEFT WILMINGTON, DE, EBOUND VFR WITH SEVERAL SMALL TSTM CELLS SHOWING ON MY RADAR TO THE E AND SE. SUDDENLY, THE SCREEN LIT UP WITH SEVERE WX IN ALL AREAS. I WAS AT THAT TIME FOLLOWING THE NEW JERSEY TURNPIKE AND ALSO USING LORAN AND VOR NAV. VISIBILITY GOT VERY LOW AND I CIRCLED VFR WHERE I THOUGHT I WAS STILL CLR OF PHILADELPHIA CLASS B AIRSPACE. I CONTACTED THE APCH CTLR, ADVISED HIM OF MY CONDITIONS AND ASKED FOR IFR ROUTING BACK TO WILMINGTON. AT THAT TIME HE ADVISED ME THAT I HAD PENETRATED PHILADELPHIA CLASS B AND WAS 4.8 NM S OF PHILADELPHIA. I TOLD HIM I WAS AVOIDING HVY WX AND INADVERTENTLY ENTERED, UNKNOWN TO ME. HE THEN CLRED ME BACK TO WILMINGTON, IFR. HE ALSO STATED MY INTRUSION WAS NO BIG DEAL AND THAT EVERYONE WAS SURPRISED BY THE INSTANT WX CHANGE GOING ON. MY CONCERN WAS KEEPING MYSELF, PAX, AND ACFT SAFE AT THIS TIME AND OBTAINING AN IFR CLRNC TO AVOID AN ACCIDENT, ETC.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.