AET Digital Electronics 2

Question 1

What is the primary characteristic of the ARINC 429 data bus used in commercial aviation?

Accepted Answer

Unidirectional single transmitter to multiple receivers

Answer

ARINC 429 is a unidirectional bus with one transmitter and up to 20 receivers, widely used in commercial transport aircraft.

Question 2

What word length does ARINC 429 use for each data transmission?

Accepted Answer

32 bits

Answer

Each ARINC 429 word is 32 bits long, containing a label, source/destination identifier, data, sign/status matrix bits, and a parity bit.

Question 3

What does a flip-flop circuit do in digital avionics systems?

Accepted Answer

Stores a single bit of data

Answer

A flip-flop is a bistable multivibrator that stores one bit of digital information, maintaining its output state until triggered to change.

Question 4

In avionics software, what does DO-178C define?

Accepted Answer

Software development and assurance levels for airborne systems

Answer

RTCA DO-178C defines the software development and verification processes required for airborne software to meet FAA certification levels (DAL A–E).

Question 5

What is the function of a data concentrator unit (DCU) in a modern avionics suite?

Accepted Answer

Collect, process, and route data from multiple avionics sensors to display systems

Answer

A DCU aggregates data from multiple avionics buses and sensors, formats it, and distributes it to cockpit display systems and other LRUs.

AET - Avionics Electronic Technicians Practice Test