How is the aircraft center of gravity envelope determined?

CG envelope defines allowable CG range for safe operation. Forward limit determined by: Elevator authority for rotation at takeoff, Nose-down pitch control in landing approach, and Trim capability at forward loading. Aft limit determined by: Longitudinal stability requirements (adequate stability margin), Nose-up recovery from stall, and Control in crosswind landing. Process: Calculate CG for various loading conditions (passengers, cargo, fuel), Analyze stability and control at each extreme, and Establish limits with safety margins. Presentation: CG envelope plotted vs. weight, showing forward and aft limits. Design impacts: Tail size trades against CG range, Fuel system sequencing maintains CG within limits, and Ballast may be needed for some configurations. Loading planning ensures actual CG always within envelope. Wider envelope provides operational flexibility but requires larger tail or other design penalties.