Ice and Rain Control (Jepp Ch 13 ALL SECTIONS)

begins with worksheet questions, then moves into my own personal questions

How and why is ice dangerous for an aircraft?

How and why is ice dangerous for an aircraft?

• Ice can change characteristics of the wing airfoil, leading to increased drag, lower stall speed, and inefficient flight.

• Increase weight

• Decrease pilot visibility

List and Describe the 4 methods of detecting ice accumulation on an aircraft

1. Visual — Look at the airfoil for ice, usually is an “ice inspection light”

2. Electronic — Small probes set in the aircraft that sense ice and display a warning on the flight deck

3. Optical — sensor on the airfoil that optically measures the thickness of the ice and transmits this to the flight deck

4. Contaminant/Fluid Integrity Measuring System (C/FIMS) — Many sensors and control boxes measure ice accumulation and the effectiveness of fluid de/anti-icing systems.

Describe how bleed air from a turbine engine can be used for an anti-ice system

• Heated air can be directed through heater ducts in the leading edges of the wings and tail surfaces in order to prevent ice formation.

• This air is usually bleed air, routed from the engines compressor section.

• The temp of the bleed air can be controlled by mixing in cold ambient air.

List and describe how the various electric anti-ice systems function.

1. Electric Pitot tubes / Static ports / AoA vanes — sensors as well as their supporting masts can be heated to prevent icing.

2. Electric Windscreens — tiny wires imbedded inside the windscreen heat up, causing ice to melt from the surface.

3. Lavatory — electric heating elements help prevent drains and water lines from freezing.

4. Turboprop engine inlets — electric boots heat up intake air

List and describe how the various forms of chemical anti-icing systems function.

1. Carburetors — Alcohol mix is sprayed into the carburetor to prevent carb or throttle icing.

2. Propellers — Uses isopropyl alcohol sprayed onto the leading edges of propeller blades. A slinger ring on the propeller uses centrifugal force to distribute alcohol to the blade nozzles.

3. Windscreens — Chemicals are sprayed through a bar located just ahead of the windscreen. this chemical coats the windscreen and prevents ice formation.

Explain the operation of a typical rubber de-icing boot system.

Several tubes attached to the leading edge of an aircrafts wing are sequentially inflated/deflated using low-pressure air (either from a pump or from a bleed air source). This inflation/deflation causes ice to break up and fly off the wing. when not inflated, a vacuum is applied to the boots to keep them secured to the wing leading edge.

List/Describe various types of maintenance and inspections that may need to be accomplished.

1. Rubber Boot systems

   1. Remove/replace boots

   2. test system for proper operation

   3. clean boots

   4. perform cold patch repair

2. Windshields

   1. Remove/Replace

   2. Ensure entire element turns on, not just some

   3. check for proper temperature

3. Chemical Anti/De-Ice

   1. Ensure system operates properly

   2. fill reservoirs

   3. check for any fluid leaks in the tank or fluid lines and fittings

4. Electrical Anti/De-Ice

   1. Ensure probles/boots heat when turned on

   2. Remove/Replace components

   3. Troubleshoot any electrical issues

List the 3 types of rain control systems

1. Windshield Wiper Systems

2. Chemical Rain Repellant

3. Pneumatic Rain Removal Systems

What is the purpose of the “PARK“ position of windshield wipers?

The PARK position allows the wipers on some aircraft to recede behind a fairing whenever they are not in use, which decreases drag and reduces the possibility of the wipers flying off in high speed flight.

How can windshield wipers be powered/actuated?

Either electrically or hydraulically

Why should you never operate wipers on a dry windshield?

The soft plastic of a windshield is easily scrapable; dry operation could cause scratches.

How does a chemical rain repellant system work?

A liquid chemical rain repellent is sprayed onto the windshield to prevent water from reaching the surface of the glass/ The water just beads up and rolls off.

How does a Pneumatic Rain Removal System work?

High-Pressure compresses air is ducted from the engine bleed air system into a plenum chamber, where it blasts a sheet of air over the windshield.

What is the purpose of a hydrophobic coating on a windshield?

To control rain by causing it to bead up and roll off the windshield.

List/Describe the typical methods of defogging an aircraft windshield

1. Electric — Use anti-ice heating elements between window panes to heat up windshield.

2. Pneumatic — A system that directs hot air between panes in the windshield, heating it up.

3. Control cabin humidity — Use environmental systems in your aircraft to eliminate excess humidity before it begins to fog the windshield.

List/Describe the typical maintenance items that would routinely need done on these rain control systems.

1. Measure tension on windshield wipers

2. Refill rain repellent tanks

3. Remove/Replace components of the various rain control systems.

4. Troubleshoot/Test system and system components

5. Replace wiper blades as they wear

6. remove and replace windshields if they are scratched or do not heat properly.