Description (AMM 34-12-01)

 

AIRPLANES WITH HONEYWELL HG480B42;

Air Data Computer

 

A- The digital air data computer (DADC) is a solid-state device that uses pitot static pressure and air temperature inputs to compute air data information required by airplane displays and systems. In addition to the above inputs, 115-volt ac and 26-volt ac are provided to multipin connectors at the rear of the computer.

 

B- The computer consists of two pressure transducers, 11 plug-in printed circuit cards, a power supply and chassis assembly. The front panel provides two switches for self-test actuation, a self-test indicator light, a fault isolation test connector for off-aircraft trouble shooting and pitot static pressure input connectors. Two electrical connectors mounted on the back of the chassis provide interconnection with the airplane wiring.

 

C- The “TEST SELECT” switch manually selects built-in test to be performed as follows:

FUNCTION - transmits fixed values on all the computer signal output lines.

SLEW - sets altitude rate to 600 feet per minute.

FAIL - activates all failure warning outputs.

 

The PUSH TO TEST pushbutton switch initiates the built-in test and the TEST VALID WHEN LIT indicator light comes on within 2 seconds after manually activated test is successfully completed and remains on if there is no failure.