Purpose of this Document

This document sets forth the air transport industry's recommended standards for the preparation of airborne navigation system reference data files. The data on these files are intended for merging with airborne navigation computer operational software to produce media for use by such computers on board aircraft. Since the industry does not desire to standardize the operational software of these computers, this merging process is not described in this document, nor do the standards set forth necessarily apply to the aircraft-employed data.

The data bases prescribed by this document are also used by computer flight planning systems, flight simulators, and other applications.

The purpose of the ARINC 424 Navigation System Data Base Standard is to be an enabling document. It enables data base suppliers, avionics systems, and other users of the data bases to fly and flight plan procedures as prescribed by procedure designers. The document is not meant to be a prescriptive document for procedure designers.

This document is also not a requirements document for airborne navigation systems.

Procedures that are not compatible with this data base standard in some cases cannot be coded for inclusion in some airborne data bases.

Coverage of Flight Simulator Needs

Supplement 4 to this document added material related to the special navigation data base needs of flight simulators. The approach taken, i.e., the definition of three new subsections to the master file and the exploitation of previously unused continuation record capability, was designed to ensure that users who wish to continue using the document solely as the basis for supporting airborne navigation system operation can do so without simulator-related records nor be concerned that the software used to merge Specification 424 data with airborne equipment operational software will need modification as the result of the changes. Users who wish to support both airborne navigation system and flight simulator operations can also do so without having to modify this merging software. Only the simulator navigation data base compilers need take into account the presence of the simulator-related components in the input (Specification 424) data.

Coverage of Flight Planning Needs

Supplement 5 of this document added material related to the special navigation data base needs to flight planning computer systems. The approach taken, i.e., the definition of the new material and the exploitation of previously unused continuation record capability, was designed to ensure that users who wish to continue using the document solely as the basis for supporting airborne navigation system operations can do so without penalty. Such users need not obtain the flight planning related records nor be concerned that the software used to merge Specification 424 data with airborne equipment operational software will need modification as the result of the changes. Users who wish to support both airborne navigation system and flight planning system operations can also do so without having to modify this merging software. Only the flight planning navigation data base systems need to take into account the presence of the flight planning related components in the input (Specification 424) data.