ARINC 600-20 PDF

It is intended that ARINC 600 be used with the application and customer needs in mind. To enhance the breadth of use, this document alludes to three phases defined as follows:

a. Phase I – This phase specifies the definitions, guidance, and appraisals given in Section 1.1 for those instances in which the aircraft manufacturer intends to randomly mix ARINC 600 boxes and ARINC 404A boxes.

COMMENTARY

In some aircraft, ARINC 600 boxes will be interspersed with ARINC 404A boxes in one rack while others will be installed in a dedicated ARINC 600 rack/cabinet. The guiding principle in this Specification is one-way generation interchangeability. ARINC 600 Phase I boxes should meet qualification requirements and fit and perform satisfactorily when installed on a Phase 0 (ARINC 404A) rack. It is recognized that a portion of the ARINC 404A rack will have to be made to accommodate the ARINC 600 Phase I boxes due to different hold-downs and different connectors. This is not to imply that cooling air will be different. Air will continue to be drawn down in ARINC 404A racks and ARINC 600 Phase I boxes will have to live with this condition. On the other hand, an ARINC 404A box could not be installed in an ARINC 600 Phase I rack/cabinet because it may be too large, it has front “dog houses,” a cooling system (e.g., holes in the sides of the LRU) that would upset the cooling provided in an ARINC 600 Phase I rack/cabinet, and for other reasons. The user of this Specification may, therefore, always install a mix of boxes in the lower numbered phase rack/cabinet and only two phases will be mixed in one rack/cabinet.

b. Phase II – This phase was envisioned to specify the definitions, guidance, and appraisals for those instances where ARINC 600 boxes are of a design catering to mechanical, electrical, and environmental control that is substantially beyond those features for Phase I. Phase II, therefore, is another step in the evolutionary development of avionic installations. As with Phase I and ARINC 404A, it is likely that aircraft manufacturers will find it necessary or convenient to sometimes mix Phase II and Phase I boxes in a rack. When this is done, the installation criteria for Phase I will prevail. However, it would not be proper to install Phase II boxes in ARINC 404A shelves. The standard rule is to always install a mix of boxes in the lowernumbered phase shelf/cabinet and no more than two phases may be mixed on one shelf. Put differently, a Phase N+1 box can be used in (and only in) a Phase N or a Phase N+1 rack/cabinet. Similarly, a Phase N box can be used only in a Phase N or Phase N-1 rack/cabinet.

COMMENTARY

The Commentary set forth in (a.) above applies. It must be clearly understood that Phase II has not been defined.

c. Phase III – This phase was envisioned to specify the definitions, guidance, and appraisals for those instances where ARINC 600 boxes are of a design catering to improved mechanical, electrical, and environmental control that is substantially beyond those features for Phase II. The criteria for mixing Phase II and Phase III boxes include the requirement that such a mix must always occur in a Phase III rack/cabinet only.

COMMENTARY

The commentary under (a.) and (b.) applies. It must be clearly understood that Phase III has not been defined. NIC Phase I Design Requirements are contained in Section 3 of this document.