Airworthiness Directives; Pilatus Britten-Norman Ltd. BN-2, BN- 2A, and BN-2B Series Airplanes

This amendment supersedes Airworthiness Directive (AD) 97-03- 03, which applies to certain Pilatus Britten-Norman Ltd. (Pilatus) BN- 2, BN-2A, and BN-2B series airplanes that do not have Modification NB/ M/1571 generator terminal diodes installed. AD 97-03-03 currently requires the installation of higher capacity diodes on the generator switches regardless of whether the airplane is equipped with the original 50 amp DC generating system or a Modification NB/M/1148, which is a 70 amp system. This action retains the actions of AD 97-03-03, but modifies the applicability section to reflect that this AD does not apply to Pilatus BN-2, BN-2A, and BN-2B series airplanes with 50 amp DC generation systems installed. This AD is the result of reports that the applicability section of AD 97-03-03 is incorrect. The actions specified by this AD are intended to prevent a loss of electrical power to the navigation, communications, and lighting systems, which could impair the pilot's ability to maintain control of the airplane.