AD FAA-2007-28990

We are adopting a new airworthiness directive (AD) for certain Boeing Model 757-200, -200CB, and -300 series airplanes. This AD requires repetitive detailed inspections with a borescope for cracks of the intercostal tee clips; or repetitive detailed inspections for cracks of the intercostal tee clips and attachment fasteners at the number 3 and number 4 doorstops of the passenger door cutouts; and related investigative and corrective actions if necessary. This AD also provides an optional terminating action for the repetitive inspections. This AD results from reports of cracked intercostal tee clips at the number 3 and number 4 doorstops of the passenger door cutouts. We are issuing this AD to detect and correct cracking of the tee clips, which could result in additional stress on the adjacent tee clips, surrounding intercostals, edge frame, door structure and doorstops. This additional stress could cause further cracking or breaking of the tee clips, which could result in failure of the door to seal and consequent rapid decompression of the airplane.