The Tactical Engagement Simulation System (TESS) was developed for the AH-64D Longbow Apache (LBA) attack helicopter, and fielded and approved as a U.S. Army Program of Record in 1998. LBA-TESS advanced training instrumentation provides aircrew the opportunity to practice live weapon engagements and combined arms training without firing a round. LBA-TESS simulates tactical weapons actions and effects in a live training environment, providing Force-on-Force and Force-on-Target live weapons training. Exercise data is actively monitored, recorded and transmitted to the Exercise Control (EXCON) display for analysis and After Action Review (AAR).

LBA-TESS customers include the United States, Netherlands, Egypt, United Kingdom, Singapore, Kuwait, Taiwan, and United Arab Emirates (UAE). Qatar and Saudi Arabia are also pursuing this training capability.

LBA-TESS is used at Combat Training Centers (CTCs) and Aviation Unit Home Stations to provide collective, combined arms training with player-to-player communications, decentralized engagement adjudication, and Real Time Casualty Assessment (RTCA). LBA-TESS interfaces electronically to the aircraft weapons system to provide a training mode, weapons mode, and a simulated weapons inventory. The advanced aircraft instrumentation system receives and transmits real-time data from the aircraft MIL-STD-1553 multiplex data bus and Discrete Laser Sensors. Realistic weapon engagements are simulated and computed using Multiple Integrated Laser Engagement System (MILES) Communication Code and Geometric Pairing for all weapons including 30mm gun, rockets, and hellfire missiles. Weapon engagements are adjudicated using Probability of Hit/Probability of Kill (Ph/Pk) algorithms specific to each weapon and player type. When a simulated round is fired, Geometric Pairing algorithms are used to calculate a trajectory and determine weapon effects.