Summary
We are revising an earlier proposed airworthiness directive (AD) for certain Model 737-200, -200C, -300, -400, and -500 series airplanes. That proposed AD would have superseded an existing AD that applies to certain The Boeing Company Model 737-200, -200C, -300, -400, and -500 series airplanes. The existing AD currently requires repetitive inspections to find fatigue cracking of certain upper and lower skin panels of the fuselage, and follow-on and corrective actions if necessary. The existing AD also includes a terminating action for the repetitive inspections of certain modified or repaired areas only. That NPRM proposed to add new inspections for cracking of the fuselage skin along certain chem-milled lines, and corrective actions if necessary. That NPRM also proposed to reduce certain thresholds and intervals required by the existing AD. This action revises that NPRM by reducing the proposed repetitive inspection intervals. We are proposing this supplemental NPRM to detectand correct fatigue cracking of the skin panels, which could result in sudden fracture and failure of the skin panels of the fuselage, and consequent rapid decompression of the airplane. Since these actions impose an additional burden over that proposed in the previous NPRM, we are reopening the comment period to allow the public the chance to comment on these proposed changes.