Summary
We propose to adopt a new airworthiness directive (AD) for certain Cessna Aircraft Company Model 750 airplanes. This proposed AD was prompted by reports of loss of displayed airspeed. This proposed AD would require inspecting certain logic modules to determine if certain cabin altitude/pitot static heater module assemblies are installed and replacing those assemblies with a new assembly; and revising the Non- Normal Procedures Section of the airplane flight manual (AFM) to include procedures for resetting the pitot switch in the event of pitot heater failure and for total loss of airspeed indication. We are proposing this AD to prevent the loss of all displayed airspeed, which could result in reduced ability to control the airplane.