Flight director system 1 & 2 Fuel temperature indicator Autopilot system Flight recorder/locator Transponder FLT management computer units 1 & 2 Inertial reference units 1, 2, & 3 FLT control augmentation computer Alternate static port AOA probe Total air temperature probe Pilot’s mach/airspeed Digital air data computer Pilot’s altimeter Auto throttle Copilot’s altimeter Static air temp gauge True airspeed indicator TAT indicator Copilot’s mach/airspeed 1 2 2 3 Computed airspeed DADC data bus DADC data bus Altitude encoding Altitude error airspeed Altitude Altitude error Computed airspeed altitude TAS Airspeed mach altitude Altitude rate TAT Static pressure Static pressure Mach Copilot’s pitot pressure Pilot’s pitot pressure Pitot pressure Static pressure Electrical connection Direction of data flow Pilot’s altimeter provides altitude signal to  flight recorder/locator if in reset mode Servo-corrected altitude In reset mode, copilot uses pilot’s static source 1 2 3 Figure 10-29.  ADCs receive input from the pitot-static sensing devices and process them for use by numerous aircraft systems.  Altimeters that measure the aircraft’s altitude by measuring  the pressure of the atmospheric air are known as pressure  altimeters. A pressure altimeter is made to measure the  ambient air pressure at any given location and altitude. In  aircraft, it is connected to the static vent(s) via tubing in the  pitot-static system. The relationship between the measured  pressure and the altitude is indicated on the instrument face,  which is calibrated in feet. These devices are direct-reading  instruments that measure absolute pressure. An aneroid or  aneroid bellows is at the core of the pressure altimeter’s  inner workings. Attached to this sealed diaphragm are the  linkages and gears that connect it to the indicating pointer.  Static air pressure enters the airtight instrument case and  surrounds the aneroid. At sea level, the altimeter indicates  10-17