Ice & Rain Protection

GENERAL DESCRIPTION

  • The aircraft’s wing, horizontal stabilizer, and vertical stabilizer leading edges are protected by pneumatic de-ice boots inflated with regulated bleed air.
  • The de-ice cycle operates automatically by timer or can be selected manually if required.
  • Engine inlet anti-ice uses unconditioned, pressure-regulated bleed air from each engine.
  • The windshields are electrically heated and defogged using 28-volt DC power. Two independent controllers regulate three heating zones per windshield. In the event of a generator failure, one essential zone on each side remains powered. Windshield heat switches on the left-hand tilt panel are normally left ON for all operations. The windshields are also hydrophobic-coated for rain removal, and the cockpit side windows use dual frost panes for defogging.
  • The pitot tubes, static ports, and stall warning vane are electrically heated through the main DC system, with one set powered by the emergency bus.
  • For ice detection, two windshield ice lights are installed on the glareshield, and a wing inspection light on the left fuselage provides illumination for visual checks during night operations.


ENGINE INLET ANTI-ICE SYSTEM

Each engine inlet leading edge is a hollow structure containing a circular piccolo tube positioned just behind its forward surface. Hot bleed air enters this tube and is dispersed through small perforations, distributing heat evenly throughout the inlet leading edge. The air then exits through a vent located on the underside of each inlet assembly, completing the anti-ice airflow path.

L and R ENGINE ANTI-ICE Switches

The L and R ENGINE ANTI-ICE switches control bleed-air flow to the engine inlet leading edges for ice protection. Each switch has two positions: L (or R) and OFF.

  • In the L/R (ON) position, hot bleed air is routed to the respective engine inlet for anti-icing.
  • In the OFF position, the PRSOV closes, blocking bleed-air flow.

ENGINE ANTI-ICE Operation

  • When icing conditions exist or are expected, place both ENGINE ANTI-ICE switches to the L and R (ON) positions. This de-energizes the shutoff valves, allowing hot bleed air to flow through the inlets and heat the engine leading edges.
  • When icing is not present or anticipated, set both switches to OFF. This energizes the shutoff valves closed, stopping bleed-air flow to the inlets, thereby improving engine efficiency and maximizing available thrust.

CAS INDICATION:

  • After turning the switch ON, the white ENG A/I COLD message appears while the inlet temperature is still below its normal operating range. Once the inlet warms to the proper temperature, the message turns off.


SURFACE DEICE (WING AND STABILIZERS)

  • The surface deice system protects the wing, horizontal stabilizer, and vertical stabilizer leading edges using regulated bleed air to inflate pneumatic boots that break and shed accumulated ice. When inflated, the boots flex the leading edges, fracturing ice so that aerodynamic forces remove it cleanly.
  • During normal operation, proper boot pressure is indicated by a white SURFACE DEICE message. If pressure is insufficient or the inflation cycle is abnormal, an amber WING DE-ICE FAIL or TAIL DE-ICE FAIL CAS alert appears.
  • The surface deice system operates in three selectable modes:
    • MANUAL: Immediate full inflation - hold switch.
    • AUTO: Automatic 2-minute inflation cycle - continuous until turned off.
    • OFF: System idle; vacuum keeps boots retracted.

SURFACE DEICE OPERATION

The wing and stabilizer deice system operates under electrical control when the WING/STAB switch is set to MANUAL or AUTO. The system inflates pneumatic boots to remove ice, with operation confirmed through cockpit indications.

MANUAL MODE

In MANUAL, the pilot directly controls boot inflation.

  • To activate, press and hold the WING/STAB switch to MANUAL.
  • All deice boots inflate and remain inflated for as long as the switch is held.
  • When proper boot pressure is achieved, the white SURFACE DE-ICE CAS message illuminates.
  • If any boot fails to pressurize, the amber WING DE-ICE FAIL and/or TAIL DE-ICE FAIL message appears.
  • Upon releasing the switch, it springs back to AUTO, but the automatic cycle is delayed for two minutes before resuming. This delay prevents immediate reinflation of the lower wing and left horizontal stabilizer boots.

AUTOMATIC MODE

In AUTO, the system operates on a timed cycle controlled by an internal timer.

  • Selecting WING/STAB → AUTO starts a 2-minute repeating sequence of inflation and deflation for all boot sets.
  • The sequence continues continuously until OFF or MANUAL is selected.
  • When OFF is selected, the system completes the current 2-minute cycle before shutting down to prevent asymmetric ice buildup.
  • During normal operation, a white SURFACE DE-ICE message confirms adequate pressure.
  • If pressure is low or the sequence timing is abnormal, the amber WING DE-ICE FAIL and/or TAIL DE-ICE FAIL message appears.

INACTIVE (OFF)

When the boots are not inflating, a vacuum holds them fully deflated, maintaining smooth airflow over the protected surfaces.



WINDSHIELD ICE AND RAIN PROTECTION

The glass windshields are equipped with electrical anti-ice and defogging systems and treated with a rain-repellent coating. Each windshield is divided into multiple electrically heated sections, providing varying levels and sources of protection to ensure clear visibility in all weather conditions.

RAIN REPELLENT

A passive hydrophobic coating on the outer windshield surface provides continuous rain-repellent protection, allowing water to bead and flow off during flight. The coating’s effectiveness decreases over time and therefore requires regular inspection and periodic reapplication to maintain optimal performance.

WINDSHIELD ANTI-ICE Switches

Windshield heating is managed by two cockpit toggle switches, one for each windshield panel (L and R WINDSHIELD ANTI-ICE). Each switch has two positions:

  • ANTI-ICE (up): Applies electrical power to both the defog and anti-ice heating zones of the respective windshield.
  • OFF: Removes power, deactivating all windshield heating functions.

SENSORS ANTI-ICE SYSTEMS

Electrical heating is supplied to prevent ice formation on the following critical sensors:

  • Pitot probes
  • Static ports
  • Stall warning vane
  • T2 (engine inlet temperature) probes

OPERATION

Selecting the PITOT STATIC position on the Sensor Anti-Ice switch powers the heaters for the pitot probes, static ports, and stall warning vane.

In Flight:

  • The switch should remain in the PITOT STATIC position at all times to ensure continuous heating of the external sensors and prevent ice formation.

On Ground:

  • Keep the switch OFF except during icing conditions or immediately prior to takeoff.
  • This prevents overheating and possible damage to the sensors and heating elements.

CAUTION

Limit ground operation of pitot-static heat to 2 minutes maximum to prevent damage to the pitot, static, and stall warning heaters.

STALL WARNING SYSTEM MODES

  • When the surface deice system is activated (by selecting the WING/STAB switch to MANUAL or AUTO), the stall-warning system automatically shifts to a higher airspeed threshold (ice-contamination mode).
  • This higher-speed mode remains active even if surface deice is later switched OFF, and will not reset automatically during flight.
  • To return the system to the normal stall-warning mode, the pilot must:
    1. Verify the WING/STAB switch is OFF, then
    2. Momentarily select RESET STALL WARN on the PITOT STATIC switch.
  • When operating in ice-contamination mode, a white “STALL WARN HI” CAS message is displayed.