Duncan Aviation logo

Cessna CIL-21-03: Water Separator Corrosion Repair

December 2022

Cessna Service Letter CIL-21-03 was released in October of 2015 to address corrosion of the water separator and its associated parts aboard Cessna 560XL and 680 aircraft. The repair consists of a cleaning process, the evaluation of the depth of corrosion pits, and a coating application to protect the area.

It isn't necessary for operators to send these units to the OEM for pressure testing the assembly. Duncan Aviation has secured the necessary tooling to complete the Cessna CIL-21-03, in its entirety providing Cessna operators a more cost-effective option with a reasonable turntime.

If you have any questions about CIL-21-03 or other technical questions about your Citation aircraft, don’t hesitate to contact me.


Inside of water separator housing full of corrosion.