Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all CASA Model CN-235 series airplanes. This proposal would require repetitive high frequency eddy current (HFEC) inspections of the flap transmission shafts to detect cracking, and repetitive functional tests (checks) to verify proper operation of the flap braking sub-system; and corrective actions, if necessary. This proposal is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to detect and correct cracking in the flap transmission shafts, and to correct a malfunctioning flap braking sub-system, which could result in the inability to move the flaps, or in an asymmetric flap condition, and consequent reduced controllability of the airplane.