AD FAA-2011-0722

We are superseding an existing airworthiness directive (AD) for certain The Boeing Company Model 737-100 and -200 series airplanes. The existing AD currently requires various inspections for cracks in the outboard chord of the frame at body station (BS) 727 and in the outboard chord of stringer (S) 18A, and repair or replacement of cracked parts. This new AD adds airplanes to the applicability statement in the existing AD and adds inspections for cracks in the BS 727 frame outboard chords and the radius of the auxiliary chord, for certain airplanes. This new AD also removes the inspections of the outboard chord of S-18A required by the existing AD. This AD was prompted by several reports of fatigue cracking in the frame outboard chord at BS 727 and in the radius of the auxiliary chord on airplanes that were not affected by the existing AD. We are issuing this AD to detect and correct fatigue cracking of the outboard and auxiliary chords, which could result in reduced structural integrity of the outboard chord and consequent rapid decompression of the airplane.