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

This amendment adopts a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-90-30 series airplanes. This action requires an inspection of the wiring of the primary and alternate static port heaters for chafing, loose connections, and evidence of arcing, and to determine what type of insulation blanket is installed in the area of the static port heaters; and corrective actions, if necessary. This action is necessary to ensure that insulation blankets constructed of metallized Mylar<SUP>TM</SUP> are removed or protected from the area of the static port heater. Such insulation blankets could propagate a small fire that is the result of an electrical short of the static port heater and could lead to a much larger fire and smoke in the cabin. This action is intended to address the identified unsafe condition.