AD FAA-2010-0646

We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires repetitive detailed inspections of the aft pressure bulkhead web for cracking, and repair if necessary. For certain airplanes, this AD also provides for an optional preventative modification of the aft pressure bulkhead web, which would terminate certain repetitive detailed inspections. This AD was prompted by reports of cracks in the aft pressure bulkhead web. We are issuing this AD to detect and correct cracking in the aft pressure bulkhead web, which could adversely affect the structural integrity of the airplane, resulting in difficulty maintaining cabin pressurization or rapid decompression of the airplane.