Airworthiness Directives; Dornier Model 328-100 and -300 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Dornier Model 328-100 and -300 series airplanes, that requires inspection of the metal oxide varistor (MOV) modules and transient absorption zener (TAZ) diodes to determine if those parts are outside of tolerance limits, and replacement of MOV modules and TAZ diodes with new parts, if necessary. This action is necessary to prevent the failure of critical ice protection systems following a lightning strike, which could result in reduced controllability and degraded performance of the airplane in the event of an encounter with icing conditions. This action is intended to address the identified unsafe condition.