Figure 15.35. Generic civil aircraft antiicing subsystem (Piccolo tubes)

to overheating. Figure 15.35 shows a typical system. Figure 15.36 depicts the BAe RJ family anti-icing system.

2.Boots. Both anti-icing and de-icing can use a boot specially designed with an integrated electrical heater or passages for hot airflow. Rubber boots are wrapped (i.e., capped) around the critical areas (e.g., LEs of lifting surfaces, propeller LEs, and intake lips) and are heated by either electrical elements or passing hot air, as in the pneumatic system. Electrically heated boots are lighter but can be relatively more expensive. The boot-type method is used in smaller aircraft. Figure 15.37 shows a typical boot system.

3.Electric Impulse. This is a not common but quite effective de-icing system. Ice is allowed to accumulate to a point when vibrations generated by electrical impulses break the ice layer, which is then blown away. This method has low power consumption but can be a heavy and expensive system.

4.Chemicals. This also is not a common system and is used primarily for anti-icing. Glycol-based antifreeze is allowed to “sweat” through small holes in critical areas where the chemical is stored. This process is limited to the amount of antifreeze carried onboard.

The piston engine carburator and critical instruments must be heated to keep them functioning.

Defogging and Rain-Removal Systems

The defogging and rain-removal systems are like an automobile using windshield wipers with embedded electrical wire in the windscreen. Rain-repellent chemicals assist in rain removal. Figure 15.38 shows a defogging and rain-removal system. Figure 15.38a is a generic layout with wipers, and Figure 15.38b shows the RJ family rain-repellent system in better detail.

15.9.8 Utility Subsystem

Utility systems are composed of water and waste systems, as shown in Figure 15.39. Passengers need water and restroom facilities. As the number of passengers and the duration of flights increase, the demand for drinking water and waste-disposal management also increases. The entire system is self-contained.

Typically, a third of a U.S. gallon of water per passenger (i.e., 100 U.S. gallons for 300 passengers) is the quantity carried onboard. Both hot and cold water is supplied. Typically, 1 lavatory per 10 to 15 passengers is provided. Chemicals are used

Figure 15.40. The RJ family wastewater system

Figure 15.41. Civil aircraft turnaround servicing locations