ARINC 429
Section 11: Aircraft & Avionics Architecture
Definition
A widely used avionics data bus standard that defines a unidirectional, point-to-point serial data bus operating at either low speed (12.5 kbit/s) or high speed (100 kbit/s). Each ARINC 429 bus has a single transmitter and up to 20 receivers. Data is transmitted as 32-bit words using a bipolar, return-to-zero modulation scheme over a twisted shielded pair of wires.
Where This Shows Up
ARINC 429, published by Aeronautical Radio, Incorporated, has been the dominant avionics data bus since the late 1970s and remains in widespread use on virtually all commercial aircraft. Its simplicity and inherent fault isolation (single transmitter, receive-only listeners) make it highly reliable and straightforward to certify. However, ARINC 429's limited bandwidth and point-to-point topology result in extensive wiring and limited data throughput for modern data-intensive applications. Each parameter is identified by a label (8-bit field) and the associated equipment address, with standard labels defined in ARINC 429 Attachment 6 and equipment-specific interface control documents.
Primary Sources
Mark 33 Digital Information Transfer System (DITS) — the complete ARINC 429 specification covering physical layer, protocol, and standard data labels.
Related Terms
Need help navigating certification?
Understanding the terminology is the first step. If you need expert guidance on DO-178C, DO-254, ARP4754B, or any aspect of FAA, EASA, or TCCA certification, our team is here to help.