Airworthiness Directives; Boeing Model 737-100, -200, -200C, -300, -400, and -500 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. For certain airplanes, this action requires repetitive inspections for discrepancies of the rear spar attachments and cracks in the upper flange of the inboard track at the rear spar attachment of each outboard flap, and eventual rework of the flap track assembly and rear spar attachments, including replacement of the flap track with a new track, if necessary. For all airplanes, this action requires repetitive inspections for cracks in the upper flange of the inboard flap tracks at the rear spar attachments, and corrective action, if necessary. The actions specified by this AD are intended to find and fix discrepancies of the inboard tracks of the outboard flaps, which could result in loss of the outboard trailing edge flaps and consequent reduced controllability of the airplane. These actions are intended to address the identified unsafe condition.