What is the function of a portable water tank?

The function of a portable water tank is to fill the potable water tank in aircraft. Potable water is essential for various onboard activities, including drinking water for passengers and crew, as well as for food preparation and hygiene purposes. A portable water tank allows ground crew to efficiently and safely transfer clean, drinkable water into the aircraft's water system, ensuring it is adequately stocked before flights.

The other functions listed, such as emptying lavatories, pumping fuel, or providing air conditioning, are handled by different specialized systems and equipment tailored to those specific tasks. Therefore, recognizing the dedicated role of a portable water tank as a supply source for potable water helps to understand aircraft ground handling operations and maintenance.