The Airbus A320 is equipped with sophisticated ice and rain protection systems to ensure safe and efficient operations in various weather conditions. Ice and rain protection system is primarily based on the principal of anti-icing, not dicing. You can check the end of this article to understand basic difference between Anti-icing and De-icing.

Protecting only the critical areas is a strategic approach that balances safety with operational efficiency and resource management.

• HOT AIR is used to protect three outboard leading-edge slats of each wing and engine air intakes
• ELECTRICAL HEATING is used to protect flight compartment windows, sensors, pilot probes and static ports, and wastewater drain mast

System can be broadly studied under following subheadings:
1. Wing Anti-Ice
2. Engine Anti-Ice
3. Window Heat
4. Probes Heat
5. Rain Removal (Wipers and Rain Repellent)
6. Ice Detection System

Wing Anti-Ice

The pneumatic system provides hot air to heat the three outboard slats on each wing, controlled by the WING pushbutton on the ANTI ICE panel. On the ground, this button can be used to initiate a 30-second test sequence. If there is a failure in the electrical power supply or a leak occurs during normal operation, the valves supplying the hot air automatically close to prevent further issues.

When the wing anti-ice system is activated, the N1 or EPR limits are automatically reduced, and the idle N1 or EPR is increased to accommodate the additional power requirements. In some MSN number WAI message appears on ECAM when thrust levers are in TOGA or FLX/MCT detent.

Engine Anti-Ice

Engine anti-ice operates independently for each engine by using an air bleed from the high-pressure compressor to protect the engine nacelles from ice. Air is supplied through a two-position (open and closed) valve, which the flight crew controls with pushbuttons for each engine. (In newer aircrafts, Two Pressure Regulated & Shut Off Valves (PRSOV) control the flow of bleed air to the engine’s air intake). Basic functioning of these valves is same.

• If the engine is not running and air is unavailable, the valve automatically closes.
• In the event of electrical power failure, these valves open automatically to ensure continued protection.

When an engine anti-ice valve is open, the N1 or EPR limits are automatically reduced, and if necessary, the idle N1 or EPR is increased for both engines to provide the required pressure.  Engine anti-ice for both the engines can be controlled independently via pushbutton switches on overhead panel.

Window Heat

Electrical heating is used to anti-ice the windshield and defog the cockpit side windows. The system includes two independent Window Heat Computers (WHC) for each side (CM1 and CM2), which automatically regulate the system, protect it from overheating, and indicate any faults.

The window heating system activates automatically when at least one engine is running or when the aircraft is in flight. It can also be manually turned on before engine start using the PROBE/WINDOW HEAT pushbutton switch. Windshield heating operates at low power while on the ground and switches to normal power during flight, with this changeover occurring automatically. For windows, only one heating level is available by default.

Probes Heat

Three independent Probe Heat Computers (PHCs) automatically control and monitor the heating of the captain’s probes, First Officer’s probes, and standby probes. These probes are heated automatically when at least one engine is running or when the aircraft is in flight, and can also be activated manually using the PROBE/WINDOW HEAT pushbutton switch. The probes heated include:

– Pitot probes
– Static ports
– Angle of attack probes
– Total air temperature (TAT) probes

Note: On the ground, TAT probes are not heated, and pitot probe heating operates at a low level. The system automatically switches to normal power during flight.

WIPERS and RAIN REPELLENT

Wiper

Each front windshield is equipped with a wiper for CM1 and CM2, respectively, featuring two speed settings. The selection knobs for controlling the wiper speeds are located on the overhead panel.

Rain Repellent

The rain repellent system is designed to improve the pilot’s visibility during heavy rain by applying a specialized repellent fluid onto the windshield. This fluid reduces the surface tension of water, causing rain to bead up and be more easily swept away by the airflow and windshield wipers.

The system is activated manually by the flight crew using a pushbutton on the overhead panel. Once activated, the system sprays a measured amount of rain repellent fluid onto the windshield.

The rain repellent system is typically used sparingly to conserve fluid. It is primarily intended for use during heavy rain conditions when wipers alone are insufficient to maintain clear visibility.

Ice Detection System

The visual ice indicator is installed externally between the two windshields. Some MSN numbers may also have ice detector probes located in the forward lower section of the fuselage. These probes detect ice accumulation and system logic generates ECAM messages based on the signals from the ice detectors and the flight crew’s selection of engine or wing anti-icing systems. It is important to note that the ice detection system does not automatically control the engine or wing anti-icing systems.

Understanding the difference between Anti-icing and De-icing

They both deal with the problem of ice accumulation but are applied at different stages and with distinct methods and objectives. Anti-icing is a preventive measure taken to stop ice from forming on aircraft surfaces while De-icing involves the removal of ice, snow, or frost that has already accumulated on an aircraft.