This paper presents some of the development, test, and evaluation, and operational test and evaluation issues testers may have to resolve when evaluating fire control systems (FCSs) against low observable air vehicles, and offers possible approaches to dealing with them. It is inevitable that stealth technology will find its way into the construction of the Advanced Tactical Fighter and Advanced Tactical Attack aircraft. Flight testers must therefore determine how effective threat fire control systems detect and destroy threat low observable aircraft. Threat fire control systems can be assessed using Foreign Technology Division's Intelligence Data Input Packages and by evaluating U.S. fire control systems against U.S. low observables. Threat FCS performance can also be estimated through computer simulations. Several RAND computer simulations revealed that an adversary would have many incentives to develop and employ low observables. This situation should motivate the tester to enhance our ability to detect, acquire, track, and destroy threat low observables.