ATA 30 - ICE / RAIN PROTECTION

• Hot air from the pneumatic system is supplied to each wing via a Pressure Control Shut-Off Valve. (only onOUT/BOARD slats 3,4,5) This valve is electrically controlled to open and pneumatically operated. (Fail safe closed, no electric power or pneumatic press) (only 3 O/B slats are protected against ice formation), Zone controller stores failure data of the wing anti ice system.

• Drain masts are heated and controlled by DEU B → CIDS Directors

• Pressure Control Shut-off Valve of wing anti-ice system has a filter inside, the valve serves as a pressure reducer in order to avoid high pressure hot air in the wing.

• ENG anti-ice valve In the absence of air pressure, the valve is spring loaded to the closed position.

• Wing / Slat Anti-ice Valve = 32 PSI

• The static ports, Angle Of Attack

(AOA),pitot and Total Air Temperature (TAT) probes are electrically heated by Probe Heat Computers (PHC) to prevent ice formation, PHC 3 is NOT linked to TAT.

• Probes and static ports heating comes on automatically when at least one engine is running.

TRICK: If we remove any of the 3 PHC (Probe Heat Computer) or any of the 2 EIU (Engine Interface Unit) probes will start heating.

• The system is made up of 2 independent sub-systems. Each one includes one Window Heat Computer (WHC), one windshield and two windows (one fixed and one sliding). Windows heating starts as soon as one of the engine is turned on.

• Windshield’s wipers are directly connected to their associated motor.

• Wind shield’s rain repellent supply line are emptied by cabin hot air supply.

• On ground, the rain repellent system is inhibited when both engines are shut down.

• To perform a complete test of the drain mast system, two tests must be carried out, one from the Programming and Test Panel (PTP), and the second on each Control Unit.

• Each Control Unit regulates the temperature range of each group of heater assemblies via their respective sensor.

• Water pipes heating control units (CU) can be found in cargo compartments and can be tested pressing related button (directly on the unit).

• The heating temperature is regulated between 6°C (42.8°F) and 10°C (50°F).The indicator illumination LED is supplied with 28VDC and controlled by the ICE IND & STBY COMPASS switch.

• The dual advisory ice detection system is made of two ice detectors installed on the aircraft skin and directly connected to the Flight Warning Computer (FWC) to send warning messages to the crew on the Engine and Warning Display (EWD).

ENGINE ICE AND RAIN PROTECTION

• Eng i-ice pressure port it is from the 5th stage HPC Anti-ice valve, the valve is spring loaded to the closed position in case of no air pressure.