Fluid is supplied to the panels and propeller by a single positive displacement, constant volume metering pump. The pump provides various flow rates to the panels and propeller. The single two speed pump provides a range of flow rates for different icing conditions.
The fluid passes through a 0.6μm – filter prior to distribution to the porous panels and propeller. The filter assures all contaminants are removed from the fluid and prevents panel blockage.
A network of nylon tubing carries the fluid to proportioning units located in the wings and tail of the aircraft. The proportioning units divide the flow into the volumetric requirements of each panel or device supplied through the unit. Each panel and device is fed again with nylon tubing.
On an aircraft being certified for FIKI the system is configured with two metering pumps, each of which can be independently operated as the primary source of fluid delivery via a toggle switch on the control panel. This configuration provides required redundancy.
There are two modes of operation for Bonanza identified as NORMAL and MAXIMUM. Normal mode represents the design flow rate for the system and is achieved by running one pump continuously in its normal setting. Maximum mode is provided as a means to navigate the maximum intermittent icing envelope, and is enabled by running one pump continuously in its maximum setting. Maximum is twice the flow rate of Normal.
The TKS system on the Bonanza includes two pressure switches. The High Pressure switch is located between the main pump and the filter. An indication of high Pressure indicates the system filter requires replacement. The Low Pressure switch is located between the filter and the proportioning units. When the TKS system is initially engaged the Low Pressure indicators will flash until the system has come up to pressure. Once the required pressure is achieved the low Pressure indicator will extinguish. An indication of low pressure after the indicator has extinguished is a serious fault and requires action is taken in accordance with procedures published in the Flight Manual Supplement.
Part 4 of the Bonanza TKS Installation can be found here.