DO-242A

DO-242A is a document published by RTCA (formerly known as Radio Technical Commission for Aeronautics). It specifies Minimum Aviation System Performance Standards (MASPS) for Barometric Vertical Navigation (Baro-VNAV) Systems. These standards are intended to support the development and certification of Baro-VNAV systems used during aircraft operations, particularly in the approach phase of flight.

Baro-VNAV relies on barometric altitude data in conjunction with lateral guidance to enable aircraft to follow a defined descent path. The DO-242A document outlines the required performance, functionality, and integrity characteristics for Baro-VNAV systems to ensure safe and reliable navigation. It addresses various aspects, including accuracy requirements for altitude measurements, system monitoring capabilities, and interfaces with other aircraft systems.

The MASPS defined in DO-242A are used by avionics manufacturers in the design and development of Baro-VNAV equipment. Furthermore, regulatory authorities, such as the Federal Aviation Administration (FAA) in the United States, may reference DO-242A in their certification guidance and regulations for Baro-VNAV operations. Compliance with DO-242A assists in demonstrating that Baro-VNAV systems meet the necessary safety and performance requirements for use in aviation.