Summary
This document proposes to supersede airworthiness directive (AD) 97-03-03, which is applicable to Pilatus Britten-Norman Ltd. (Pilatus) BN-2, BN-2A, and BN-2B series airplanes that do not have generator terminal diodes installed with Modification NB/M/1571. This AD currently requires removing the terminal diodes that have a 70 amp direct current (DC) Generation System, referred to as Modification NB/ M/1148, and installing Modification NB/M/1571, which consists of new terminal diodes with a higher amp rating. The proposed action would retain the same actions required in AD 97-03-03, and would change the applicability section of the proposed AD. Reports from operators that one or both diodes were failing prompted this action, as well as reports from operators that the applicability section of AD 97-03-03 was wrong. The actions specified by this AD are intended to prevent a loss of electrical power to the navigation, communications, and light systems, which could impair the pilot's ability to maintain control of the airplane.