Action
Notice of proposed rulemaking (NPRM).
Summary
The FAA proposes to supersede an existing airworthiness directive (AD) that applies to certain Boeing 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. This proposed AD would add new inspections for cracking of the fuselage skin along certain chem-milled lines, and corrective actions if necessary. This proposed AD would also reduce certain thresholds and intervals required by the existing AD. This proposed AD results from reports of new findings of vertical cracks in the fuselage skin along the chem-milled steps adjacent to the butt joints. We are proposing this AD to detect and 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.