AST 473 Cessna Citation II- CE-550 Systems Dr. Barnhart Ice & Rain System

AST 473AST 473Cessna Citation II- CE-550Cessna Citation II- CE-550

SystemsSystems

Dr. BarnhartDr. Barnhart

Ice & Rain SystemIce & Rain System

Anti-Ice, De-Ice, and Rain Anti-Ice, De-Ice, and Rain Protection SystemsProtection Systems

• Anti-Ice Systems:Anti-Ice Systems:– WingWing– Engine ComponentsEngine Components– Windshield (bleed air and isopropyl alcohol)Windshield (bleed air and isopropyl alcohol)– Pitot-Static/AOA systemsPitot-Static/AOA systems

*All components should be activated prior to *All components should be activated prior to entering icing conditionsentering icing conditions

De-Icing SystemsDe-Icing Systems

• Pneumatic boots on outboard wing Pneumatic boots on outboard wing sections, horizontal and vertical tail sections, horizontal and vertical tail segments.segments.

*Activated upon ice accumulation*Activated upon ice accumulation

Rain ProtectionRain Protection

• Compressor bleed air directed Compressor bleed air directed through louvers provides a layer of through louvers provides a layer of air directing rain off of the air directing rain off of the windscreen.windscreen.

Anti-Ice General DetailAnti-Ice General Detail

• Engine Anti-Ice Protection:Engine Anti-Ice Protection:– T(1) Temp. probe (bleed air)T(1) Temp. probe (bleed air)– Nose Cone (bleed air)Nose Cone (bleed air)– Nacelle Inlet (bleed air)Nacelle Inlet (bleed air)– 11stst set of engine stator vanes (bleed air) set of engine stator vanes (bleed air)– Inboard Wing sections (electric)Inboard Wing sections (electric)– Nose cone and T(1) probe are continually Nose cone and T(1) probe are continually

protected while the others require the protected while the others require the engine anti-ice switch to be positioned onengine anti-ice switch to be positioned on

Pitot/Static Anti-IcePitot/Static Anti-Ice

• Pilot switch controls DC power to two Pilot switch controls DC power to two pitot masts, four static ports, and the AOA pitot masts, four static ports, and the AOA probe (breakers located on pilot’s panel)probe (breakers located on pilot’s panel)

• P/S HTR OFF annunciator illuminates P/S HTR OFF annunciator illuminates anytime power is disrupted to this circuit anytime power is disrupted to this circuit (switch off or failure- AOA heater not on (switch off or failure- AOA heater not on this warning circuit)this warning circuit)

*Ground operation to P/S Heat limited to *Ground operation to P/S Heat limited to two minutes to prevent AOA probe two minutes to prevent AOA probe damage.damage.

Windshield Anti-Ice and Rain Windshield Anti-Ice and Rain RemovalRemoval

• Anti-Ice protection controlled via a Anti-Ice protection controlled via a three-way switch (hi, low, and off) on three-way switch (hi, low, and off) on pilot’s panel, which, along with the pilot’s panel, which, along with the two bleed air valve control knobs two bleed air valve control knobs direct bleed air to the windshielddirect bleed air to the windshield– Main power switch de-energizes the Main power switch de-energizes the

windshield bleed-air valve open and windshield bleed-air valve open and activates a temp. controlleractivates a temp. controller

Windshield Anti-iceWindshield Anti-ice

• HI position- 138 +/- 5 deg.- use when HI position- 138 +/- 5 deg.- use when OAT is At or below -18 deg. C , Low 127 OAT is At or below -18 deg. C , Low 127 +/-5 deg.- use when OAT is above -18 +/-5 deg.- use when OAT is above -18 deg. Cdeg. C

• Temp. is maintained by the temp. Temp. is maintained by the temp. controller which receives 3 inputs:controller which receives 3 inputs:– W/S Bleed switch positionW/S Bleed switch position– 2 ea. Temp. sensor inputs2 ea. Temp. sensor inputs*Sensor modifies amt. of ram air passing *Sensor modifies amt. of ram air passing

through the heat exchangerthrough the heat exchanger


• Modified Bleed air then passes through a Modified Bleed air then passes through a series of nozzles onto the windscreenseries of nozzles onto the windscreen

• Additional temp. sensor located in the Additional temp. sensor located in the bleed air duct- automatically energizes bleed air duct- automatically energizes closed the electric bleed air solenoid closed the electric bleed air solenoid valve if bleed air temp. > 146 deg. C.valve if bleed air temp. > 146 deg. C.– At this point the W/S Air O’HEAT annunciator At this point the W/S Air O’HEAT annunciator

illuminates (happens at high power/low illuminates (happens at high power/low airspeed config.- valve resets and light airspeed config.- valve resets and light extinguishes automatically upon correctionextinguishes automatically upon correction


• If the W/S AIR O’HEAT light If the W/S AIR O’HEAT light illuminates with the switch OFF:illuminates with the switch OFF:– Bleed-air valve opened pressurizing the Bleed-air valve opened pressurizing the

duct- sensed by a duct pressure switchduct- sensed by a duct pressure switch– Pilot action: ensure W/S Bleed Valves Pilot action: ensure W/S Bleed Valves

OFFOFF– NOT an over pressure but a valve NOT an over pressure but a valve

position warningposition warning


• In DC failure: Bleed air Solenoid valve In DC failure: Bleed air Solenoid valve opens- W/S bleed air avail. But no opens- W/S bleed air avail. But no O’Heat warning and temp cnt’l are O’Heat warning and temp cnt’l are inop.inop.

• Operation of system is verified by the Operation of system is verified by the noise when valves are open thus noise when valves are open thus damage should be prevented in a DC damage should be prevented in a DC pwr. failurepwr. failure

Windshield AlcoholWindshield Alcohol

• Back up to W/S Bleed systemBack up to W/S Bleed system

• Components:Components:– Reservoir- 2 qts. Capacity isopropyl alcoholReservoir- 2 qts. Capacity isopropyl alcohol– Switch- W/S ALCOHOL- 2 pos.Switch- W/S ALCOHOL- 2 pos.– PumpPump– NozzlesNozzles

*Up to 10 min. protection- pilot’s side only- fluid *Up to 10 min. protection- pilot’s side only- fluid qty. verified on pre-flight via a sight gauge in rt. qty. verified on pre-flight via a sight gauge in rt. Hand nose cmpt.Hand nose cmpt.

Rain Removal SystemRain Removal System

• Uses Bleed air from Windshield De-ice Uses Bleed air from Windshield De-ice system via doorssystem via doors

• Activated by pulling open the PULL RAIN Activated by pulling open the PULL RAIN handle under W/S Bleed Air knobshandle under W/S Bleed Air knobs– Rotate W/S Bleed air knobs to MAXRotate W/S Bleed air knobs to MAX– Position W/S Bleed switch to LOWPosition W/S Bleed switch to LOW– During low power settings (landing) rotate co-During low power settings (landing) rotate co-

pilot’s W/S Bleed Air knob to OFFpilot’s W/S Bleed Air knob to OFF– RAIN handle hard to pull of bleed air already onRAIN handle hard to pull of bleed air already on

Engine Anti-IceEngine Anti-Ice

• Meant as an ice preventative measure- Meant as an ice preventative measure- activation after ice accumulation can activation after ice accumulation can cause engine damagecause engine damage

• Activate when OAT is between +10 Activate when OAT is between +10 and -30 deg. Cand -30 deg. C

• For sustained Ground operation in For sustained Ground operation in visible moisture at the above temps. visible moisture at the above temps. Activate engine anti-ice for 1 min. out Activate engine anti-ice for 1 min. out of 4 AOA 65%N(2).of 4 AOA 65%N(2).


• Components:Components:– Electric Heating elements in inboard scn. Of Electric Heating elements in inboard scn. Of

each wing leading edgeeach wing leading edge– Bleed air heated engine nacelle inletsBleed air heated engine nacelle inlets– First row of stationary stators behind the First row of stationary stators behind the

first state fan and prior to the booster stagefirst state fan and prior to the booster stage– Nose Cone and T(1) probe continually onNose Cone and T(1) probe continually on– Activated by ENGINE ANTI-ICE switch on Activated by ENGINE ANTI-ICE switch on

pilot’s panelpilot’s panel

Engine Anti-Ice OperationEngine Anti-Ice Operation

• Select ENGINE ANTI-ICE ON:Select ENGINE ANTI-ICE ON:– If engines above 60% for > 5 sec. (throttle If engines above 60% for > 5 sec. (throttle

micro-switch) 2 bleed-air solenoid valves micro-switch) 2 bleed-air solenoid valves de-energize open allowing bleed air to flow de-energize open allowing bleed air to flow to nacelle inlet and stator vanesto nacelle inlet and stator vanes•Look for a Rise in ITT and a slight drop in RPMLook for a Rise in ITT and a slight drop in RPM

•5 sec. time delay built in to aid in faster engine 5 sec. time delay built in to aid in faster engine spool up during periods of high demand (ie. spool up during periods of high demand (ie. Go-around)Go-around)

Engine Anti-Ice OperationEngine Anti-Ice Operation

• ENG ANTI-ICE LH/RH annunciators ENG ANTI-ICE LH/RH annunciators illuminate when switches placed on illuminate when switches placed on and extinguish when nacelle inlet and extinguish when nacelle inlet temps. >224 deg. F AND Stator vane temps. >224 deg. F AND Stator vane bleed-air solenoid valve open, AND bleed-air solenoid valve open, AND wing leading edge heaters are wing leading edge heaters are operating w/ temp AOA 60 deg. Foperating w/ temp AOA 60 deg. F


• Annunciator will re-illuminate for any of Annunciator will re-illuminate for any of the following:the following:– Stator valve fails to open (5s delay normal)Stator valve fails to open (5s delay normal)– Nacelle leading edge temp < 104 deg. CNacelle leading edge temp < 104 deg. C– Inboard wing scn. Temp < 16 deg. CInboard wing scn. Temp < 16 deg. C– Failure of 1 or > wing heat elements (Light Failure of 1 or > wing heat elements (Light

will illuminate each cycle if one failed)will illuminate each cycle if one failed)– Failure of the temp. controller (light cycles Failure of the temp. controller (light cycles

off when the leading edges are heated and off when the leading edges are heated and on when temp. limit is reached).on when temp. limit is reached).

Engine Anti-Ice CautionEngine Anti-Ice Caution

• During descents in icing conditions During descents in icing conditions avoid throttle settings below 60% as avoid throttle settings below 60% as engine bleed-air solenoid valves will engine bleed-air solenoid valves will close (annunciator will illuminate)close (annunciator will illuminate)

Wing Anti-Ice SystemWing Anti-Ice System

• 5 elec. Heating elements in each wing each 5 elec. Heating elements in each wing each with it’s own CB and current sensor powered with it’s own CB and current sensor powered by main DC buses respectivelyby main DC buses respectively

• Operated when power is on regardless of Operated when power is on regardless of throttle position.throttle position.

• Maintains skin temp. bet. 54 and 78 CMaintains skin temp. bet. 54 and 78 C

• Over-temp sensor on upper surface (cooler) Over-temp sensor on upper surface (cooler) activates at 75 C and opens circuit maintaining activates at 75 C and opens circuit maintaining temp. @ 69 C.- Activates ENG ANTI-ICE LH/RHtemp. @ 69 C.- Activates ENG ANTI-ICE LH/RH

Wing Anti-Ice SystemWing Anti-Ice System

• Operation monitored by illumination of Operation monitored by illumination of green lights above each ignition switch, green lights above each ignition switch, illumination of the ENG ANTI-ICE LH/RH illumination of the ENG ANTI-ICE LH/RH annunciator and a 150 amp rise on each annunciator and a 150 amp rise on each ammeter.ammeter.

• If throttles are above 60% N(2)If throttles are above 60% N(2)• During Electrical Failure both nacelle inlet During Electrical Failure both nacelle inlet

valve and stator vane valve will fail open valve and stator vane valve will fail open and engine will be anti-iced continuouslyand engine will be anti-iced continuously

De-Ice SystemDe-Ice System

• Boots on outer wing leading edges, and Boots on outer wing leading edges, and horizontal and vert. stabilizerhorizontal and vert. stabilizer

• Controlled by SURFACE DE-ICE Switch Controlled by SURFACE DE-ICE Switch on pilot’s instrument panelon pilot’s instrument panel

• Bleed air is available to system when Bleed air is available to system when engines operating- timer switch controls engines operating- timer switch controls automatic sequencing of boot operationautomatic sequencing of boot operation

• Power is via SURFACE DE-ICE CBPower is via SURFACE DE-ICE CB

De-Ice System OverviewDe-Ice System Overview

• Activate when ¼ to ½ inch of ice presentActivate when ¼ to ½ inch of ice present• Use ½ inch thick stall strip on wing leading Use ½ inch thick stall strip on wing leading

edge as a guide- early activation may edge as a guide- early activation may cause bridging- (use L. wing inspn. Light)cause bridging- (use L. wing inspn. Light)

• Ice thicker than ½ inch may not be able to Ice thicker than ½ inch may not be able to be removed by bootsbe removed by boots

• If DC fails- avoid icing conditionsIf DC fails- avoid icing conditions• Avoid activation below -40Deg. C- boot Avoid activation below -40Deg. C- boot

damage may occurdamage may occur

De-Ice System OperationDe-Ice System Operation

• SURFACE DE-ICE switch- de-energized SURFACE DE-ICE switch- de-energized to OFF- all 3 control valves de-energizedto OFF- all 3 control valves de-energized

• In OFF the 3 valves are dumping bleed In OFF the 3 valves are dumping bleed air overboard via venturis that create air overboard via venturis that create vacuum to hold boots deflatedvacuum to hold boots deflated

• To cycle boots momentarily place switch To cycle boots momentarily place switch in SURFACE DE-ICE Position- energized in SURFACE DE-ICE Position- energized system timer for 2 ea.6 sec. cycles- 1system timer for 2 ea.6 sec. cycles- 1stst cycle is empennage (wings held tight)cycle is empennage (wings held tight)

De-Ice System OperationDe-Ice System Operation

• 22ndnd cycle- wings (empennage held tight) cycle- wings (empennage held tight)• After 12 seconds (2 ea. 6 sec. cycles) all 3 After 12 seconds (2 ea. 6 sec. cycles) all 3

valves are de-energized closed and vacuum valves are de-energized closed and vacuum is applied to all boots to hold closedis applied to all boots to hold closed

• During operation (as each set is inflated) the During operation (as each set is inflated) the white SURF DEICE annunciator is illuminated white SURF DEICE annunciator is illuminated by a pressure switchby a pressure switch

• In the event of a malfunction and boots In the event of a malfunction and boots remain inflated- cycle switch to RESET- remain inflated- cycle switch to RESET- overrides the system timer and de-energizes overrides the system timer and de-energizes all control valves- holds boots deflated.all control valves- holds boots deflated.

The EndThe End

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AST 473 Cessna Citation II- CE-550 Systems Dr. Barnhart Ice & Rain System