Performs the final flight line servicing, checkout, trouble shooting, repairing and maintenance of completed aircraft electrical and instrument systems, related lines and accessories prior to, during and after flight, and sells off entire functional systems, accessories and components for airworthiness and conformance to Company and customer requirements; operates, trouble shoots and makes final adjustments to entire electrical diagnosing and correcting any malfunctioning revealed by such operational checkout while such systems are operating under auxiliary power or power instrument systems, accessories and components to authorized Company and/or customer personnel. Installs shortages; incorporates design or modification changes to ship's electrical and instrument systems, lines, and related accessories; makes adjustments, calibrations, alterations, repairs, corrections, and replacements as required.