It is likely that you never heard of this incident. However, it had a major impact on my life as I was that instructor. Neither the instructor-in-charge, other instructors, nor students recognized the clearly visible indicators of a ventilation controlled fire and potential for backdraft that were visible from the exterior. No one involved in this training exercise anticipated the impact of horizontal ventilation on fire behavior during this trainig exercise. This incident ignited my passion for understanding fire dynamics, reading the fire, and predicting likely fire behavior.