ARINC SPECIFICATION 424-21-2016 PDF

Full title and description

ARINC Specification 424-21-2016 — Navigation System Data Base. Recommended industry standard describing the fixed‑record format, field definitions and encoding rules used to prepare airborne navigation system database files for flight management and navigation equipment.

Abstract

ARINC 424-21 (Release 21, 2016) defines the data format and coding conventions for navigation system databases used by airborne navigation and flight management systems. The specification covers user file organization, record layouts, field definitions, and encoding rules required to represent airports, runways, navaids, waypoints, airways, SIDs, STARs, approaches and other procedure elements — enabling interoperable navigation database production and exchange between data suppliers, avionics manufacturers and aviation service providers.

General information

• Status: Revised (Release/Issue of the ARINC 424 series).
• Publication date: July 25, 2016 (Release 21 / 424-21).
• Publisher: Aeronautical Radio, Inc. (ARINC).
• ICS / categories: ICS 49 (Aerospace engineering) — on‑board equipment and avionics/navigation data (commonly referenced under ICS 49.090 / aircraft avionics/navigation).
• Edition / version: Release 21 (ARINC 424-21, 2016). Note: the ARINC 424 series has subsequent releases (most recently Release 23 / 2022 edition).
• Number of pages: Approximately 480–490 pages (typical PDF/hardcopy edition listings report ~487 pages).

Scope

Specifies a fixed‑length record format and a comprehensive set of coded record types and field definitions for creating airborne navigation databases. Scope includes file organization for airline and helicopter user files, detailed record layouts for waypoints, navaids, airports/runways, airways, departure/arrival/approach procedures, coding rules (bit density, parity conventions, labels), and special encodings for modern navigation constructs such as PBN/RNP elements and RF (radius‑to‑fix) legs. The standard is intended for database producers, avionics integrators and related toolchains that prepare navigation data for operational flight software.

Key topics and requirements

• Fixed 132‑byte record format and record type catalogue.
• User file organization for airline and helicopter database files.
• Field definitions and encoding rules for airports, runways, navaids, waypoints, airways, SIDs, STARs and approaches.
• Coding conventions: headers, labels, bit density, parity and reel‑file relationships.
• Support for performance‑based navigation (PBN) elements, RF legs and vertical path coding used in modern procedures.
• Guidance on handling non‑standard or not‑fully‑codable procedures and reserved fields for future enhancements.

Typical use and users

Primary users include navigation database suppliers, avionics and FMS manufacturers, flight‑planning and dispatch systems, procedure designers, flight simulator/data‑integration vendors, and regulatory authorities who review database coding for procedure publication and validation. Integrators use the specification to produce database media consumable by airborne navigation equipment.

Related standards

Part of the ARINC 424 series (multiple releases: earlier and later releases such as 424-20, 424-22, 424-23). Related material and operational datasets include national/regional CIFP datasets and ICAO/Eurocontrol guidance on procedure design and PBN; avionics interface standards and ARINC reports that address onboard data handling are also complementary.

Keywords

ARINC 424, navigation database, FMS, avionics, waypoints, navaids, SIDs, STARs, approaches, record layout, PBN, RF leg, database encoding, ARINC 424-21, Release 21, ARINC.

FAQ

Q: What is this standard?

A: ARINC Specification 424-21 is Release 21 (2016) of the ARINC 424 Navigation System Data Base specification — the industry coding standard for preparing airborne navigation database files used by FMS and navigation equipment.

Q: What does it cover?

A: It covers file organization, fixed record formats, record types, field definitions, encoding rules and conventions needed to represent airports, runways, navaids, waypoints, airways and instrument procedures (SIDs, STARs, approaches), including modern PBN elements.

Q: Who typically uses it?

A: Navigation data suppliers, avionics/FMS manufacturers, flight‑planning and dispatch systems, procedure designers, simulator vendors and regulatory/air navigation authorities.

Q: Is it current or superseded?

A: The 424-21 document is the 2016 Release 21 edition. The ARINC 424 series is periodically updated; later releases (for example Release 23 / 2022) have been published, so 424-21 should be treated as a historical release where implementers are expected to reference the latest release for new systems.

Q: Is it part of a series?

A: Yes — ARINC 424 is a series of releases (numbered supplements/releases) maintained by AEEC/ARINC; each release (e.g., 424-18, 424-20, 424-21, 424-22, 424-23) updates or extends the coding rules and record types.

Q: What are the key keywords?

A: Navigation database, ARINC 424, fixed record format, field definitions, FMS, avionics, PBN, RF leg, SIDs, STARs, approaches.