Colonel Scott A. Snook, Ph.D., in Friendly Fire1 introduced the term practical drift.The theory of practical drift emergedfrom Snook’s root cause analysis of a1994 friendly fire accident in which two U.S. Air Force F-15C Eagle fighter jets patrolling the No-Fly-Zone over northern Iraq shot down two U.S. Army Black Hawk UH-60 helicopters. Twenty-six peacekeepers lost their lives.

The theory of practical drift postulates that even though organizations develop elaborate plans and procedures for dealing with routine and emergency situations, when a situation (e.g., a fire, explosion, injury, etc.) occurs, these plans and procedures fall prey to on-scene modification due to conditions encountered at the scene.