If the air data computer fails in a plane equipped with an electronic flight display, which instrument is affected?

In an aircraft equipped with an electronic flight display (EFD), the air data computer is responsible for processing input from various sensors to provide critical flight data, including airspeed, altitude, vertical speed, and sometimes heading information. If the air data computer fails, it loses its ability to calculate real-time air data, like temperature, pressure, and other parameters necessary for determining airspeed.

The airspeed indicator relies on the information processed by the air data computer to display the current airspeed of the aircraft accurately. Without this data, the airspeed indicator may become unreliable or inoperative, directly impacting the pilot's ability to gauge the aircraft's speed accurately.

Other instruments, while they may have some degree of independence, typically either rely on the air data computer for information or are not directly affected by its failure. The altimeter and vertical speed indicator also depend on the processed pressure data from the air data computer, making them vulnerable to the same failure. The heading indicator, however, usually relies on the magnetic compass or other systems and may continue to function despite the air data computer's failure, distinguishing it from the other instruments described. Thus, the airspeed indicator is the instrument most directly and critically affected in this scenario.