Airworthiness Directives; British Aerospace Jetstream Model 3101 Airplanes

This action confirms the effective date of Airworthiness Directive (AD) 98-21-28, which applies to certain British Aerospace Jetstream Model 3101 airplanes. AD 98-21-28 requires modifying the propeller de-icing system to assure system performance at low ambient temperatures. This AD was the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the United Kingdom. The actions specified in this AD are intended to prevent propeller-induced vibrations from occurring during icing encounters at low ambient temperatures, which could result in decreased performance of the de-icing system during icing encounters with possible loss of control of the airplane.