Plain English Meaning
Using everyone and everything available — the other pilot, the autopilot, ATC, checklists, written guidance — to fly the aircraft safely, instead of trying to handle everything alone or letting tasks slip through the cracks.
Full Definition
Crew resource management is the structured use of all available resources — people, equipment, information, and procedures — to achieve safe and efficient flight operations. It covers communication, task delegation, workload distribution, decision-making, situational awareness, and the effective use of crew members and outside support such as ATC, dispatchers, and maintenance.