Aircraft Fuel System Water Management

Aircraft Fuel System Water Management

Duncan Woods

The topic of water and ice in aircraft fuel systems is complex. Water can cause a variety of system and equipment effects, including fuel gauging system malfunctions and icing of equipment in fuel tanks and in engine feed lines which can lead to other operational issues.  Effective water management is therefore key in avoiding these issues and in minimising operational costs.


WEC has supported its clients in developing leading edge systems and equipment solutions to manage water in fuel. This work has resulted in safer and more reliable fuel systems on a number of different aircraft platforms.

One project involved a large passenger aircraft with an extremely complex fuel system. Following fuel system design improvements implemented by the client, WEC was tasked with establishing if the scheduled water drain task interval could be extended and if so, by how much?


The project

To enable us to establish a justification for safely extending the water drain task interval:

  • We performed thorough analyses of fuel system design, in-service data and system operation.
  • We developed a model to simulate the “water cycle” throughout the fuel system in order to establish permissible quantities of water to be drained. Use of the in-service data was key in developing a validated and verified model.
  • Working closely with the Client, we were able to create a procedure which operators used to evaluate aircraft water drainage quantity patterns annually throughout the route structure.
Drawings overhead

The benefit

The resultant procedure was used to evaluate stepped extensions to the water drainage interval, based on the client’s own water drainage data, whilst ensuring that compliance with design and certification fuel system requirements was maintained.

The drainage data and the aircraft fuel system model were used successfully to validate and verify the stepped extension to the water drainage interval that the operators had sought. This enabled operators to safely extend the periodicity of schedules maintenance checks, thereby reducing their operating costs.

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