Airworthiness Directives; Saab Model SAAB 340B Series Airplanes Equipped with Hamilton Sundstrand Propellers

This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB 340B series airplanes equipped with Hamilton Sundstrand propellers. This amendment requires a one-time inspection of two remote controlled circuit breakers (RCCB), located in specific electrical compartments, to identify the part number, and replacement of the RCCBs with new RCCBs having a different part number if necessary. This action is necessary to ensure removal of 35-ampere (amp) RCCBs on a 50-amp electrical circuit. Incorrect RCCBs on an electrical circuit could result in erroneous tripping of the RCCBs (even though an overload condition does not exist), premature failure of the RCCBs, loss of power to the feather pump system, and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.