Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 737-100 and - 200 series airplanes. This proposal would require inspections to detect cracking of the support fittings of the Krueger flap actuator; and replacement of existing fittings with new steel fittings and modification of the aft attachment of the actuator, if necessary. This proposal is prompted by reports of cracking due to fatigue and stress corrosion of the support fittings of the Krueger flap actuator. The actions specified by the proposed AD are intended to prevent such cracking, which could result in fracturing of the actuator attach lugs, separation of the actuator from the support fitting, severing of the hydraulic lines, and resultant loss of hydraulic fluids. These conditions, if not corrected, could result in possible failure of one or more hydraulic systems, and subsequent reduced controllability of the airplane.