air is a Time and Space Partitioned Real Time Operative System (RTOS) implementing the application executive (APEX) defined by the ARINC 653 specification.

With ARINC 653, air defines support for robust partitioning in safety-critical systems, especially in the aviation domain.

Robust partitioning is a technique to execute several safety-critical real-time applications on the same processing resource, i.e. a module with processor, main memory and some networking and I/O facilities.


air technology makes the following possible in an RTOS:

  • Strict conformity with ARINC 653 specification
  • Unrestricted temporal and spatial partitioning
  • Hardware and operating system independent solution
  • Unique enhanced scheduling and functional features (see key features for more details).