ARINC 826

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[ARINC 826 is an avionic data loading protocol for data loading of avionics][1] over the Common Area Network (CAN) bus. It allows Loadable Software Aircraft Parts (LSAP) to be loaded in a verifiable and secure manner to avionics Line Replaceable Units (LRUs) and Line Replaceable Modules (LRMs) using CAN.

Based on a subset of ARINC 615A features (the avionic data loading protocol for data loading over Ethernet), ARINC 826 provides basic features for avionics data loading.

ARINC 826 is also known informally as the "Armagnac Protocol" as it was first conceived and documented on a cocktail napkin in a bar in a hotel in Toulouse, France over several glasses of Armagnac. It is also commonly referred to as "the diminutive protocol".

ARINC 826 was originally conceived to have both an "A" version and a "B" version. The "A" version was originally intended to be a more complex protocol where ARINC 615A messages would be encapsulated in CAN messages. This was implemented in the Boeing 787 in a derived form. The "B" version was designated to be the simplest of possible data loading protocols, designed for data loading of simple avionics of which the example of a "data loadable" coffee pot is often used.

The "A" version was dropped when this proved cumbersome in 787 applications. The "B" version was expanded to have more features which made it suitable for general avionics.

The requirement for a reliable and robust CAN bus data loading protocol has come about because of the increased use of CAN for avionics applications in next generation aircraft. CAN provides a low cost substitute for ARINC 429, the traditional avionic protocol.