ICE PROTECTION

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ICE PROTECTION
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ICE PROTECTION

• Airborne icing is one of the most challenging
  aspects of IFR flight.
• In order for an aircraft to be certified for
  flight in known or forecast ice it must be
  properly equipped.
• Electrical ice systems are usually among the
  highest draw systems on an aircraft, while
  pneumatic systems deprive the engine of power.
• There are two categories of ice protection
• De-ice equipment removes ice which has
  accumulated.
• Anti-ice equipment prevents ice from
  accumulating.

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LEADING EDGE PROTECTION

• Pneumatic boots (de-ice) use a pneumatic source
  to inflate rubber leading edge boots, which
  removes adhering ice.
• Usually inflate in a timed sequence.
  (inboardtail, outboard) A manual inflation
  feature protects against timer failure. All
  surfaces inflate at once.
• Usually have a minimum temperature associated
  with operation.
• Inflation distorts wing shape and disrupts
  airflow.
• The source of air is dependant on aircraft type
• Bleed air (turbine)
• Turbocharger (turbocharged)
• Air pump (normally aspirated)

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LEADING EDGE PROTECTION

• Heated leading edge (anti-ice) hot bleed air is
  piped through leading edge.
• Has negative affect on engine power, and should
  always be off for take-off.
• Some systems may not be used on ground, as the
  heat can deform the leading edge.

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LEADING EDGE PROTECTION

• Weeping wing (anti-ice) glycol based de-ice
  fluid is forced through a porous leading edge.
• The air stream distributes the fluid evenly
  across the leading edge.
• No power loss or aerodynamic penalty associated.
• The fluid can weep back beyond the leading edge.
• The system ads substantial weight and the fluid
  supply must be replenished.

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WINDSCREEN PROTECTION

• Ice on the windscreen doesnt have an appreciable
  aerodynamic effect, but the reduced visibility
  associated must be protected against.
• There are two types of windshield anti-ice in
  use.
• Electric
• Fluid

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WINDSCREEN PROTECTION

• Electric (de-ice/anti-ice) an electric element
  is laminated into the glass.
• Distorts vision when on, should be off for
  take-off and landing unless absolutely necessary.
• Aftermarket versions are available which attach
  the outer surface of the windscreen.

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WINDSCREEN PROTECTION

• Fluid (de-ice/anti-ice) glycol fluid weeps onto
  the windscreen.
• Distorts vision almost as much as ice would.
• Must time the actuation to allow for the fluid to
  flow off of windscreen before transitioning to
  visual.
• Fluid must be replenished.

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PROPELLER PROTECTION

• Ice accumulation on propellers can lead to
  imbalance and vibration causing failure.
• The propeller de-ice of choice comes in the form
  of electrically heated boots. Some fluid systems
  are available.
• The boots cycle on a timer to remove ice.
• Do not operate de-ice when propeller is not
  turning or the brush blocks and slip rings may
  fuse.
• Ice shedding form the propellers can contact the
  fuselage and re-enforcement is necessary. The
  sound can also be quite disconcerting.

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ENGINE PROTECTION

• Turbine engines must be protected against ice
  ingestion, which could cause extensive damage.
• Ice collecting on the engine inlet lip could
  break free and be ingested by the engine.
• Heated inlets are used to prevent the
  accumulation of ice.
• The inlet is heated by one of these common
  methods
• Engine bleed air
• Exhaust air
• Electric elements

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BRAKE DE-ICE
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OTHER ICE PROTECTION

• Pitot heat
• Heated stall vanes
• Heated static ports
• Fuel heaters
• Heated fuel vents
• Some of these systems are attached to squat
  switches in order to vary the heat intensity to
  different levels for ground and flight operation.