POTABLE WATER, WASTE AND SERVICE-STATE PERSISTENCE
Potable water, wastewater drainage and toilet-waste storage are distinct systems. The supplied description identifies a potable-water tank and distribution to galleys/lavatories, wastewater disposal, and separate toilet-waste retention. A single cabin-service percentage cannot be assumed to represent all three. Servicing fills or empties particular stores; a flight-plan import or changed destination is an information task rather than evidence that those services have occurred. This is why turnaround checks must include the actual service state. [84, PDF pp. 2–6]
The reference potable-water arrangement uses pressure to distribute water and provides service/fill/drain and local isolation functions. The source distinguishes airborne pressurisation from the ground-service arrangement. These are physical dependencies, not commands to search for a maintenance valve in the Fenix cockpit. A lack of supply can arise from quantity, pressurisation or local isolation rather than an empty tank alone. The controls described in the historical manual must be identified by installed effectivity before drawing operational conclusions. [84, PDF p. 3] [67, PDF p. 2]
Wastewater drainage and toilet-waste storage have different paths and contamination implications. The source includes insulated/heated drainage provisions to address leakage and ice concerns. Those details explain why cabin servicing cannot be reduced to the passenger count. Equipment faults can affect a local cabin function without producing the same cockpit indications as a loss of flight-deck cooling or pressurisation. Keep the affected location and function explicit when comparing a cabin report with the FAP or system information. [84, PDF pp. 4–6] [87, PDF p. 163]
V3 documents water/waste information and servicing as part of its cabin workflow. Use the supported interface and confirm the resulting quantities rather than assuming each new sector resets the stores. The public documentation establishes the supported service-state feature; it does not prove that every physical drain mast, local shutoff or tank-sensor fault is separately modelled. For an advanced turnaround exercise, record the arrival quantities, requested services, observed completion and the departure state. That makes persistence and service effects testable without inventing hidden component interactions. [53, Flight Attendant Panel chapter; water/waste and servicing] [81, Supported Virtual Purser/cabin workflow] [84, PDF pp. 2–6]