FUNCTIONAL CHECKS OF CHEMICAL DE-ICING SYSTEMS:
Once the correct flow rate of the fluid supply has been established the distribution of the fluid flow over the blades should be checked. This check is carried out with the engine(s) running and all the necessary safety precautions must to be observed. The following operations are carried out prior to the ground run:
- The overshoe grooves are checked to ensure that there is no build up of gummy deposits obstructing the flow of fluid (cleaning will be discussed later in this booklet).
- The blades should be pained with a disclosing fluid or whitewash, as directed by the propeller manufacturer.
- A dye should be added to the contents of the de-icing tank.
- The engine is then run at the RPM laid down in the manual.
- For a specified period the system is turned on, and at the correct rate if a rheostat is fitted.
- The fluid with added dye will stain the disclosing fluid and when the engine has stopped the blades van be examined for even distribution.