Airworthiness Directives; Rockwell Collins, Inc. ADC-85, ADC-85A, ADC-850D, and ADC-850F Air Data Computers

This amendment adopts a new airworthiness directive (AD) that applies to certain Rockwell Collins, Inc. (Rockwell Collins) ADC-85, ADC-85A, ADC-850D, and ADC-850F air data computers that are installed on airplanes. This AD requires you to replace any affected air data computer (ADC) with one that has a reprogrammed and tested central processing unit (CPU) circuit card and circuit card assembly. This AD is the result of a flight test that showed that these ADC's could display an unwarranted ADC flag in response to the airplane's "Normal/ Alternate Air" static source selection capability. The actions specified by this AD are intended to prevent an unwarranted display of the ADC flag when switching static air sources. This could cause the flight crew to react to this incorrect flight information and possibly result in an unsafe operating condition.