What are the basic requirements for aircraft fuel systems?

Fuel system requirements: Storage - Sufficient volume for design mission plus reserves, typically in wing (structural efficiency) and center section, sometimes fuselage tanks; Distribution - Transfer fuel to engines reliably, sequencing to maintain CG within limits, and crossfeed capability for engine failure; Management - Quantity indication (capacitance probes), automatic or crew-managed transfer, and fuel temperature monitoring; Safety - Vent system (prevents structural damage from pressure), lightning protection, crash resistance, fire prevention (ullage inerting), and contamination prevention. System components: Tanks (integral, bladder, or rigid), Pumps (boost, transfer, engine-driven), Valves (shutoff, crossfeed, transfer), and Refueling/defueling interfaces. Design considerations: Unusable fuel minimization, Fuel cooling for engine/APU, and De-icing using warm fuel. FAR 25 Fuel System requirements ensure reliable fuel delivery in all conditions.