Fill it to the rim

It has been long understood that the issue of potable water management, and subsequently the roughly 500lbs (225kg) of additional weight that water adds to a flight, is ineffective when resorting to the standard ground practice of “fill to spill.”

If you are unfamiliar with the terminology, fill-to-spill means exactly what it sounds like. Ground crews are instructed to fill the potable water tank to the overflow line (spilling) prior to each flight. The problem is, without a system to effectively predict how much potable water an aircraft needs to carry in its tank for specific flights, the aircraft ends up carrying unnecessary weight. In some case, up to 440lbs/200kg.

A university study on the evaluation of airline fuel saving, which has been backed up by IATA, found that potable water weight management was one of the most effective ways to save fuel. As a matter of fact, it was the most effective after winglets.

Weight and position

It’s not only the additional weight that creates sustainability problems, it’s also the effect that weight has on the aircraft's flight performance. We spoke with our Business Development Director, Kevin Parker, about what excess water weight means in terms of efficiency.

“An excess weight of 440lb/200kg is significant, but the positioning of the weight in the tail of the aircraft also causes efficiency degradation known as induced drag. The weight and balance of an aircraft is critical to optimize flight performance.”

“Weight that is further from the centre of the aircraft will affect efficiency more because it essentially uses the wing as a fulcrum. As the distance increases from the centre of the aircraft, the weight becomes more problematic and directly affects the efficiency of the aircraft.”

Water weight management: Starting from scratch or further optimising your system?

Digital services

Quick Links

Quick Links

Legal Links

How much water is too much water on a flight?