Airworthiness Directives; McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 Series Airplanes; Model DC-9-81 (MD-81), -82 (MD-82), -83 (MD-83), and -87 (MD-87) Airplanes; and Model MD-88 Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 series airplanes; Model DC-9-81 (MD-81), -82 (MD-82), -83 (MD- 83), and -87 (MD-87) airplanes; and Model MD-88 airplanes; that requires repetitive inspections and functional tests of the static port heater assemblies, and corrective actions if necessary. The actions specified by this AD are intended to prevent an electrical short of the static port heater from sparking and igniting the insulation blanket adjacent to the static port heater, which could result in smoke and/or fire in the cabin area. This action is intended to address the identified unsafe condition.