AST 473 Cessna Citation II CE550 Systems

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AST 473Cessna Citation II- CE-550Systems

• Dr. Barnhart
• Ice Rain System

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Anti-Ice De-Ice and Rain Protection Systems

• Anti-Ice Systems
• Wing
• Engine Components
• Windshield (bleed air and isopropyl alcohol)
• Pitot-Static/AOA systems
• All components should be activated prior to
  entering icing conditions

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De-Icing Systems

• Pneumatic boots on outboard wing sections
  horizontal and vertical tail segments.
• Activated upon ice accumulation

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Rain Protection

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

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Anti-Ice General Detail

• Engine Anti-Ice Protection
• T(1) Temp. probe (bleed air)
• Nose Cone (bleed air)
• Nacelle Inlet (bleed air)
• 1st set of engine stator vanes (bleed air)
• Inboard Wing sections (electric)
• Nose cone and T(1) probe are continually
  protected while the others require the engine
  anti-ice switch to be positioned on

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Pitot/Static Anti-Ice

• Pilot switch controls DC power to two pitot
  masts four static ports and the AOA probe
  (breakers located on pilots panel)
• P/S HTR OFF annunciator illuminates anytime power
  is disrupted to this circuit (switch off or
  failure- AOA heater not on this warning circuit)
• Ground operation to P/S Heat limited to two
  minutes to prevent AOA probe damage.

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Windshield Anti-Ice and Rain Removal

• Anti-Ice protection controlled via a three-way
  switch (hi low and off) on pilots panel
  which along with the two bleed air valve control
  knobs direct bleed air to the windshield
• Main power switch de-energizes the windshield
  bleed-air valve open and activates a temp.
  controller

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Windshield Anti-ice

• HI position- 138 /- 5 deg.- use when OAT is At
  or below -18 deg. C Low 127 /-5 deg.- use when
  OAT is above -18 deg. C
• Temp. is maintained by the temp. controller which
  receives 3 inputs
• W/S Bleed switch position
• 2 ea. Temp. sensor inputs
• Sensor modifies amt. of ram air passing through
  the heat exchanger

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Windshield Anti-ice

• Modified Bleed air then passes through a series
  of nozzles onto the windscreen
• Additional temp. sensor located in the bleed air
  duct- automatically energizes closed the electric
  bleed air solenoid valve if bleed air temp. 146
  deg. C.
• At this point the W/S Air OHEAT annunciator
  illuminates (happens at high power/low airspeed
  config.- valve resets and light extinguishes
  automatically upon correction

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Windshield Anti-ice

• If the W/S AIR OHEAT light illuminates with the
  switch OFF
• Bleed-air valve opened pressurizing the duct-
  sensed by a duct pressure switch
• Pilot action ensure W/S Bleed Valves OFF
• NOT an over pressure but a valve position warning

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Windshield Anti-ice

• In DC failure Bleed air Solenoid valve opens-
  W/S bleed air avail. But no OHeat warning and
  temp cntl are inop.
• Operation of system is verified by the noise when
  valves are open thus damage should be prevented
  in a DC pwr. failure

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Windshield Alcohol

• Back up to W/S Bleed system
• Components
• Reservoir- 2 qts. Capacity isopropyl alcohol
• Switch- W/S ALCOHOL- 2 pos.
• Pump
• Nozzles
• Up to 10 min. protection- pilots side only-
  fluid qty. verified on pre-flight via a sight
  gauge in rt. Hand nose cmpt.

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Rain Removal System

• Uses Bleed air from Windshield De-ice system via
  doors
• Activated by pulling open the PULL RAIN handle
  under W/S Bleed Air knobs
• Rotate W/S Bleed air knobs to MAX
• Position W/S Bleed switch to LOW
• During low power settings (landing) rotate
  co-pilots W/S Bleed Air knob to OFF
• RAIN handle hard to pull of bleed air already on

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Engine Anti-Ice

• Meant as an ice preventative measure- activation
  after ice accumulation can cause engine damage
• Activate when OAT is between 10 and -30 deg. C
• For sustained Ground operation in visible
  moisture at the above temps. Activate engine
  anti-ice for 1 min. out of 4 AOA 65N(2).

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Engine Anti-Ice

• Components
• Electric Heating elements in inboard scn. Of each
  wing leading edge
• Bleed air heated engine nacelle inlets
• First row of stationary stators behind the first
  state fan and prior to the booster stage
• Nose Cone and T(1) probe continually on
• Activated by ENGINE ANTI-ICE switch on pilots
  panel

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Engine Anti-Ice Operation

• Select ENGINE ANTI-ICE ON
• If engines above 60 for 5 sec. (throttle
  micro-switch) 2 bleed-air solenoid valves
  de-energize open allowing bleed air to flow to
  nacelle inlet and stator vanes
• Look for a Rise in ITT and a slight drop in RPM
• 5 sec. time delay built in to aid in faster
  engine spool up during periods of high demand
  (ie. Go-around)

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Engine Anti-Ice Operation

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

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Engine Anti-Ice

• Annunciator will re-illuminate for any of the
  following
• Stator valve fails to open (5s delay normal)
• Nacelle leading edge temp
• Inboard wing scn. Temp
• Failure of 1 or wing heat elements (Light will
  illuminate each cycle if one failed)
• Failure of the temp. controller (light cycles off
  when the leading edges are heated and on when
  temp. limit is reached).

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Engine Anti-Ice Caution

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

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Wing Anti-Ice System

• 5 elec. Heating elements in each wing each with
  its own CB and current sensor powered by main DC
  buses respectively
• Operated when power is on regardless of throttle
  position.
• Maintains skin temp. bet. 54 and 78 C
• Over-temp sensor on upper surface (cooler)
  activates at 75 C and opens circuit maintaining
  temp. _at_ 69 C.- Activates ENG ANTI-ICE LH/RH

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Wing Anti-Ice System

• Operation monitored by illumination of green
  lights above each ignition switch illumination
  of the ENG ANTI-ICE LH/RH annunciator and a 150
  amp rise on each ammeter.
• If throttles are above 60 N(2)
• During Electrical Failure both nacelle inlet
  valve and stator vane valve will fail open and
  engine will be anti-iced continuously

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De-Ice System

• Boots on outer wing leading edges and horizontal
  and vert. stabilizer
• Controlled by SURFACE DE-ICE Switch on pilots
  instrument panel
• Bleed air is available to system when engines
  operating- timer switch controls automatic
  sequencing of boot operation
• Power is via SURFACE DE-ICE CB

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De-Ice System Overview

• Activate when ¼ to ½ inch of ice present
• Use ½ inch thick stall strip on wing leading edge
  as a guide- early activation may cause bridging-
  (use L. wing inspn. Light)
• Ice thicker than ½ inch may not be able to be
  removed by boots
• If DC fails- avoid icing conditions
• Avoid activation below -40Deg. C- boot damage may
  occur

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De-Ice System Operation

• SURFACE DE-ICE switch- de-energized to OFF- all
  3 control valves de-energized
• In OFF the 3 valves are dumping bleed air
  overboard via venturis that create vacuum to hold
  boots deflated
• To cycle boots momentarily place switch in
  SURFACE DE-ICE Position- energized system timer
  for 2 ea.6 sec. cycles- 1st cycle is empennage
  (wings held tight)

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De-Ice System Operation

• 2nd cycle- wings (empennage held tight)
• After 12 seconds (2 ea. 6 sec. cycles) all 3
  valves are de-energized closed and vacuum is
  applied to all boots to hold closed
• During operation (as each set is inflated) the
  white SURF DEICE annunciator is illuminated by a
  pressure switch
• In the event of a malfunction and boots remain
  inflated- cycle switch to RESET- overrides the
  system timer and de-energizes all control valves-
  holds boots deflated.

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The End