The effects of a chemical defense protective drug, pyridostigmine bromide (PB), on inflight aircrew performance were assessed using the Total In-Flight Simulation (TIFS) aircraft. This aircraft was used as both a ground and inflight simulator supplying appropriate control feel, handling characteristics, and cockpit instrumentation for a tactical-transport simulation. Twenty-one C-130 pilots flew two familiarization and four data flights. As part of this study, video recordings of aircrew behavior from preflight through landing were analyzed using an incident analysis technique. Behaviors were grouped in 23 categories including irritability, humor, and accidental activation. The frequencies of occurrences of each of these behaviors by drug (PB or placebo) and crew position (pilot or copilot) are presented as well as an assessment of the utility of the incident analysis technique in drug research.