What methods are used for aircraft weight estimation?

Weight estimation methods vary by design phase: Conceptual - Statistical/historical: Empty weight fraction vs. MTOW correlation, Component weight fractions from similar aircraft, and Regression equations (Raymer, Roskam, Torenbeek); Preliminary - Class II methods: Component-level equations based on geometry, Design parameters, and loading, Higher fidelity for wing, fuselage, landing gear, etc.; and Detailed - Actual part weights: CAD-based mass properties, Bottom-up from parts lists and drawings, and Vendor-provided equipment weights. Weight buildup: Structure (wing, fuselage, empennage, gear), Propulsion (engines, nacelles, systems), Systems (hydraulic, electric, avionics, etc.), and Furnishings (seats, galleys, lavatories). Accuracy improves as design matures: Conceptual +/- 10-15%, Preliminary +/- 5%, Detail +/- 2%. Weight tracking throughout development is critical for performance guarantees.