HEIR, GENERAL. Heir at common in the English law. The heir at common law is he who, after his father or ancestor's death has a right to, and is introduced into all his lands, tenements and hereditaments. He must be of the whole blood, not a bastard, alien, &c.
An air data computer (ADC) is a avionics component that assimilates the inputs from an aircraft's external and system sensors and returns a series of calculated results critical to the control of the aircraft. In one compact package, the air data computer performs what a bank of individual instruments were once required to do. Almost all the flight-related information displayed in newer commercial aircraft fitted with glass cockpits is compiled by an air data computer.
Air traffic control. Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through controlled airspace, and can provide advisory services to aircraft in non-controlled airspace.