Quiz & Flashcards on Propeller De-Icing Systems

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Questions and Answers

What is the purpose of the slip-ring and brush assembly on the spinner bulkhead?

To measure the temperature of the propeller blades

To reduce the weight of the propeller

To provide a tight seal for the propeller de-icer

To transmit current to the boot for de-icing (correct)

Which of the following is a characteristic of a chemical propeller deicing system?

It is used on most commercial airliners

It is commonly used on single-engine GA aircraft (correct)

It is a pneumatic system

It is only used for wing deicing

Why should aircraft be de-iced as close to takeoff time as possible?

To reduce the holdover time (correct)

To reduce the risk of engine failure

To improve the aircraft's aerodynamics

To reduce the weight of the aircraft

What is the recommended method for removing wet snow deposits from an aircraft?

Using a brush or squeegee Signup and view all the answers

What is the purpose of the timer in an electric propeller de-icing system?

To control the heating time and sequence of the de-icing cycle Signup and view all the answers

What is the recommended method for removing ice from the inside of a turbine engine?

Flowing hot air through the engine until all moving parts move freely Signup and view all the answers

What is the purpose of removing paint from the area to be covered by the de-icer boots during installation?

To ensure a stronger bond between the boot and the wing Signup and view all the answers

What is the primary disadvantage of using rivet nuts and screws to attach de-icer boots?

It creates a rougher airfoil surface Signup and view all the answers

What should be done to de-icer boots before installing them on a wing?

Clean them with a mild soap and water solution Signup and view all the answers

What is the effect of ice formation on the propeller leading edges, cuffs, and spinner?

It reduces the powerplant system's efficiency Signup and view all the answers

What type of system uses electrical heating elements to deice propellers?

Electrothermal Propeller Device System Signup and view all the answers

What should be checked during an operational check of a pneumatic de-icer system?

Both the suction and pressure gauges Signup and view all the answers

What is the primary purpose of an oil separator in a pneumatic de-icer system?

To remove oil from the air before it is used to inflate the de-ice boots Signup and view all the answers

What type of pump is used to create a vacuum for operating the flight instruments in a pneumatic de-icer system?

Vacuum pump Signup and view all the answers

What is the function of the pressure control valve in a pneumatic de-icer system?

To control the amount of pressure allowed in the system Signup and view all the answers

What is the purpose of a timer module in a pneumatic de-icer system?

To sequence the de-icer boots through one complete de-ice cycle Signup and view all the answers

What type of air pump is used in newer installations of pneumatic de-icer systems?

Dry-type pump Signup and view all the answers

What is the purpose of the de-icer boots in a pneumatic de-icer system?

To inflate and deflate to remove ice from the leading edge of the airfoil Signup and view all the answers

Study Notes

Propeller De-Icer Systems

The boot is permanently attached and gets current from a slip ring and brush assembly.
Electrically heated de-icers are bonded to propeller blades for effective ice removal.
Components of the electric de-icer system include slip-ring and brush assemblies, timers, ammeters, and circuit breakers.

Chemical De-Icing Systems

Some single-engine general aviation aircraft utilize chemical de-icing systems.
Ice forms on propellers before wings, necessitating prompt treatment on propeller systems.
The chemical system may work in conjunction with wing de-icing systems, like the TKS™ weeping system.

Ground De-Icing Procedures

Frost removal involves spraying a de-icing fluid with ethylene glycol and isopropyl alcohol.
Wet snow should be removed using brushes or squeegees; avoid sharp tools.
Holdover time is the duration a de-iced surface remains free from ice, snow, or frost.
De-icing should occur close to takeoff to minimize holdover time.

Turbine Engine Ice Removal

Hot air should flow through the engine to melt ice from turbine engines, ensuring all parts move freely.

Inspection and Maintenance of De-Icer Boots

During pneumatic de-icer system checks, observe suction and pressure gauges for proper reading patterns.
The pressure gauge fluctuates as de-icer tubes inflate/deflate; the vacuum gauge remains steady.
Two primary methods for securing rubber de-icer boots are adhesives and rivnuts/screws.
Bonded de-icer boots offer a smoother airfoil compared to those attached with rivet nuts/screws.

Installation Guidelines

All paint must be removed from areas where surface-bonded de-icer boots are applied to ensure proper bonding.
De-icer boots should be kept free of contaminants like oil or dirt and cleaned with mild soap and water.

Efficiency Reduction Due to Ice Formation

Ice on propeller leading edges, cuffs, and spinners decreases the powerplant efficiency.
Two main types of de-icing systems: electrical and chemical.

Electrothermal Propeller Device System

Electrically heated boots on propeller blades are widely used for de-icing.
An oil separator removes oil from the air before it's used, preventing damage to boots.
Newer "dry-type" air pumps are increasingly used for these systems, negating the need for oil separators.

Pneumatic De-Icing System Components

Air Pump: A vacuum pump creates a vacuum for flight instruments and provides air pressure to inflate de-icer boots.
Vacuum Regulator: Controls the vacuum level applied to de-icer boots and flight instruments.
Pressure Control Valve: Manages the pressure within the de-icing system.
Timer Module: Activates a timer for the de-icer boots’ cycle and shuts off after completing a cycle, applying a vacuum until the next activation.
Other components may include filters, valves, and various tubing for overall system functionality.

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Description

This quiz covers the components and types of propeller de-icing systems used in aircraft, including electric and chemical methods.

Airplane Propeller De-Icing Systems