A Combat Systems Officer (or CSO, differs from CSOp) is a flight member of an aircrew in the United States Air Force and is the mission commander in many multi-crew aircraft. The combat systems officer manages the mission and integrates systems and crew with the aircraft commander to collectively achieve and maintain situational awareness and mission effectiveness. CSOs are trained in piloting, navigation, the use of the electromagnetic spectrum, and are experts in weapon system employment on their specific airframe. Aircrew responsibilities include mission planning, mission timing, weapons targeting and employment, threat reactions, aircraft communications, and hazard avoidance.