Validating the electronic combat environment (ECE) in aircrew training devices (ATD) is a process that compares the operating parameters and performance of the electronic warfare (EW) portions of ATDs to the current intelligence assessment of threat weapons systems, documents the differences and assesses their impacts, and authenticates the representations and interactions. Real world threats are constantly evolving and EW reprogramming centers routinely update mission software to counter the developing threats. These changes and updates affect many different mission aspects regarding aircrew threat perceptions and reactions including detection, identification, and countermeasures effectiveness. This paper details the processes involved and illustrates the benefits of an ECE validation program for ATDs.