Which system is described as an aircraft computer that receives and processes pitot pressure, static pressure, and temperature to calculate altitude, indicated airspeed, true airspeed, and air temperature?

• A. An onboard weather radar unit
• B. An aircraft computer that receives and processes pitot pressure, static pressure, and temperature to calculate altitude, indicated airspeed, true airspeed, and air temperature.
• C. A device that measures cabin pressure.
• D. A navigation computer for route planning.

Answer: (B)

The system described is the air data computer (ADC) in the air data system. It takes signals from the pitot tube (total or pitot pressure), from the static pressure ports, and from an outside air temperature sensor. Using these inputs, it computes the essential air data: altitude, indicated airspeed, true airspeed, and outside air temperature. Indicated airspeed comes directly from the dynamic pressure derived from pitot and static pressures. Altitude is determined from the static pressure (with corrections for temperature), and true airspeed adjusts indicated airspeed for air density, which depends on both altitude and outside air temperature. The outside air temperature input is also used to compute true airspeed and to display the outside air temperature.

This is distinct from onboard weather radar (which looks for weather phenomena), a device measuring cabin pressure (which monitors cabin pressure levels), or a navigation computer (which handles route planning and navigation).