Airworthiness Directives; McDonnell Douglas Model MD-90-30 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-90-30 series airplanes, that requires replacement of certain ground block screws with new screws; and retermination of the circuit ground wires of the electrical power control unit (EPCU) to separate grounding points. This amendment is prompted by reports of complete loss of the primary electrical power on an airplane during flight. The actions specified by this AD are intended to prevent a loose electrical ground block of the circuit ground wires of the EPCU, which could result in complete loss of the primary electrical power of an airplane during flight.