How is weight growth managed during aircraft development?

Weight growth threatens performance guarantees and must be actively managed. Sources: Design maturity (initial estimates conservative), Requirements changes, Systems growth (wiring, ducting), Manufacturing realities, and Customer options. Management process: Weight budget - Allocate targets to subsystems at program start, Track actual vs. target weight continuously, Weight action items when overweight. Control: Weight review board authority, Trade studies for weight vs. other attributes, Value engineering for weight reduction, and Kill-a-gram programs (incentives for weight savings). Tools: CATIA mass properties, Component weight tracking database, and Weight reports (weekly or more frequent). Critical phases: PDR, CDR, first hardware, first flight, certification. Consequences: 1% weight increase = ~0.5% range loss, Potential payload reduction, and Possible fuel burn penalties affecting competitive positioning. Weight engineering team dedicated to tracking and reduction. Empty weight guarantee to customers can have significant financial consequences.