Integrating a Helmet Mounted Cueing System (HMCS) in a fast jet is a challenging task. Successful integration is subjected to numerous factors, from which system latency is one of the most important. An excellent mounted cueing system design by itself may not satisfy the latency requirements at the aircraft level. The bigger latency is, the bigger the gap between real world situation and the interpretation of this situation as presented to the pilot through his HMCS. System latency may induce difficulties in target acquisition by the pilot and other sensors of the aircraft (missile, radar, FLIR, weapon, etc.), it reduces pilot situation awareness and degrades system accuracy and performance. These effects may vary in different avionics configurations as well as in diversified flight conditions. This paper discusses the nature of latency effects in aircraft level, latency operational characteristics and requirements, and recommends approaches and methods to help overcome these effects.