Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Saab Model SAAB SF340A and SAAB 340B series airplanes. This proposal would require inspections to detect damage or cracking of the forward and aft attachment lugs of the flap fittings at wing station (WS) 123.38; an inspection to verify that the sizes of the holes of the flap fittings are within specified limits and to ensure that the swaged bushings are not loose; and modification of the flap fittings. This proposal is prompted by a report of jamming of a flap due to incorrect tolerances of the flap-hinge installation, which caused high bearing stress on the bushings in the flap fittings. The actions specified by the proposed AD are intended to prevent such high bearing stress, which could result in wear on the bushings, cracking of the flap fittings, and breakage of the lugs; these conditions could result in jamming of the flaps and consequent reduced controllability of the airplane.