effects of icing

8/11/2019 Effects of Icing

1/45


2/45

TQM

2


3/45

3


4/45

4


5/45

5


6/45

6


7/45

7


8/45

To apprise the house regarding icing and itseffects on aircraft

AIM

8

Effects Of Icing On Aircraft


9/45

Introduction

Super-cooled Water Droplets

Condensation

The Freezing Process

Types Of Aircraft Ice

Factors Affecting Icing

SEQUENCE

9



10/45

The Effects of Icing on Aircraft

Strategies For Avoiding Icing

De-icing Methods

Conclusions

SEQUENCE

10



11/45

SUPER-COOLED DROPLETS

11

Nominal freezing point of water 0C

Water droplets capable of freezing

Formed bycondensation



12/45

Gaseous state into liquid state

Reverse of vaporization

CONDENSATION

12Click



13/45

Supercooled water droplet strikes

Unfrozen part of the droplet spreads

THE ICING PROCESS

13



14/45

1) Rime Ice

Product of small droplets

Opaque and brittle

Forms on the

leading edges

Low adhesiveproperties

TYPES OF ICING

14



15/45

2) Clear Ice

Large droplet does not freeze completely

Each drop merges and spreadsbackwards

high adhesive

properties

TYPES OF ICING

15



16/45

Transparent to a very tough opaque

TYPES OF ICING

16



17/45

3) Mixed Ice

Mixture of rime ice and clear ice

More adhesive properties

Opaque in appearance

Rough and builds forward

TYPES OF ICING

17


18


18/45

4) Hoar frost

Light crystalline deposit

Air directlyFreezes over the a/c

TYPES OF ICING

18


19


19/45

a) Liquid Water Content

b) Temperature

c) Droplet sized) Cloud type

e) Airfoil geometry

f) Airspeedg) Duration of exposure

THE FACTORS AFFECTING ICING

19


20


20/45

a) Liquid Water Content

Dependent on the size and number of

droplets

Greater the liquid water content, the more

icing potential


20


21


21/45

b) Temperature

Affects severity and type of icing

0C and -25

C, severe clear icing

-25C and -40C, light rime icing

below -40C, little chance of icing


21


22


22/45

c) Droplet Size

Freezing drizzle or freezing rain

Supercooled LargeDroplets (SLD)


22


23


23/45

d) Aerofoil geometry

Modern wings more critical


23


24


24/45

e) Airspeed

Greater airspeed,

Rapid ice formation


24


25


25/45

Effects onWing and tail surfaces

Disturbs the air flow

Reduce their lift

Increase the

drag/stalling

Speed

EFFECTS OF ICING ON AIRCRAFT

25


26


26/45

Effects onPropeller

Reduces propeller efficiency

Vibration on the propeller

Excessive

stress


26


27


27/45

Effects on Controls

Control surfaces may jam

Reduce their effectiveness


27


28


28/45

Pitot tube and Static Pressure Ports

Inaccurate height and airspeed


28


29


29/45

Radio Antennae

Loss of radio communication


29


30


30/45

Icing on Engine


30


31


31/45


Icing on Engine


32


32/45

Weather Briefing Tips

Areas of FZRA (freezing rain) and FZDZ

(freezing drizzle)

50% relative humidity

Centre of a low pressure system

STRATEGIES FOR AVOIDING ICING


33


33/45

Never fly with frost on your aircraft

Use early warning devices

Corona indicates presence of water

Use pitot heater

Stay clear of clouds

Gentle control movementsUse carburettor heat



34


34/45

Stabilized landing approach



35


35/45

On Ground de-icing methods:

1. Aircraft De-icing Fluids

2. Hot Water Aircraft De-icing3. Forced Air De-icing System

DE-ICING METHODS


36


36/45

1. Aircraft De-icing Fluids (ADF)

Type I, Type II, Type III, Type IV

propylene glycol or ethylene glycol

Type I and Type IV are the most

commonly used

DE-ICING METHODS


37


37/45

2. Hot Water Aircraft De-icing

Heat and distribute water

Fewer operating costs

DE-ICING METHODS


38


38/45

3. Forced Air De-icing System

Delivers high-pressure air

Effective inremoving dry,

powder snow

DE-ICING METHODS


39


39/45

1. Pneumatic Systems

2. Bleed Air System

3. Electro Thermal Systems

IN FLIGHT DE-ICING METHODS


40


40/45

1. Pneumatic systems

Pneumatic de-icing boots

Periodically inflated Automatically

controlled



41


41/45

2. Bleed Air system

Bled from engines

May operateautonomously



42


42/45

3. Electro thermal systems

Electrically heated resistive elements

First function as de-icing systems, thenas anti-icingsystems



43


43/45

CONCLUSION


44


44/45

45


45/45

effects of icing

Documents