Description / Abstract: DO-204A incorporates numerous changes to clarify the meaning and intent of the requirements. Text revisions and explanatory notes have been added. COSPAS/SARSAT testing criteria and DO-183 tests have been incorporated into the specification. G-Switch characteristics have been replaced. The document is harmonized with EUROCAE ED-62. Includes test conditions and procedures for installed equipment performance for emergency locator transmitters (ELTs) utilizing the 406.0 to 406.1 MHz band and operating in the COSPAS-SARSAT system.