A_M11.12_2012.07.12

(1)

Revision: Revision: Author: Author:

For Training Purposes Only For Training Purposes Only 

LTT 2007LTT 2007

Module

Ice and Rain Protection

EASA Part-66

A

EJ EJ MM11.1211.12 AA EE SaR SaR

11.12

(ATA 30)

JUN2 JUN2 12.07.2012 12.07.2012

(2)

Training Manual

For training purposes and internal

use only.



Copyright by Lufthansa Technical Training (LTT).

LTT is the owner of all rights to training documents and

training software.

Any

use

outside

the

training

measures,

especially

reproduction and/or copying of training documents and

software

−−

also extracts there of

−−

in any format at all

(photocopying, using electronic systems or with the aid

of other methods) is prohibited.

Passing on training material and training software to

third parties for the purpose of reproduction and/or

copying is prohibited without the express written

consent of LTT.

Copyright endorsements, trademarks or brands may

not be removed.

A tape or vi

deo recording

of training c

ourses or

similar

services is only permissible with

the written consent of

LTT.

In other

respects, legal requirements

, especially under

copyright and

criminal law, apply.

Lufthansa Technical Training

Dept HAM US

Lufthansa Base Hamburg

Weg beim Jäger 193

22335 Hamburg

Germany

T

el

:

+4

9 (

0)

40

5

07

07 0 2

0 2

52

0

0 Fa

Fa

x:

+4

9 (

0)

40

50

70

47

46

46 www.Lufthansa-Technical-Training.com

www.Lufthansa-Technical-Training.com



 The date given in the column ”Revision” on the face of The date given in the column ”Revision” on the face of

this cover is binding for the complete Training Manual.



 Dates and author’s ID, which may be given at the baseDates and author’s ID, which may be given at the base

of the individual pages, are for

of the individual pages, are for information about theinformation about the

latest revision of that page(s) only.



 The LTT production process ensures that the TrainingThe LTT production process ensures that the Training

Manual contains a complete set of

Manual contains a complete set of all necessary pagesall necessary pages

in the latest finalized revision.

Revision Identification:

(3)

For training purposes and internal

use only.



Copyright by Lufthansa Technical Training (LTT).

LTT is the owner of all rights to training documents and

training software.

Any

use

outside

the

training

measures,

especially

reproduction and/or copying of training documents and

software

−−

also extracts there of

−−

in any format at all

(photocopying, using electronic systems or with the aid

of other methods) is prohibited.

Passing on training material and training software to

third parties for the purpose of reproduction and/or

copying is prohibited without the express written

consent of LTT.

Copyright endorsements, trademarks or brands may

not be removed.

A tape or vi

deo recording

of training c

ourses or

similar

services is only permissible with

the written consent of

LTT.

In other

respects, legal requirements

, especially under

copyright and

criminal law, apply.

Lufthansa Technical Training

Dept HAM US

Lufthansa Base Hamburg

Weg beim Jäger 193

22335 Hamburg

Germany

T

el

:

+4

9 (

0)

40

5

07

07 0 2

0 2

52

0

0 Fa

Fa

x:

+4

9 (

0)

40

50

70

47

46

46 www.Lufthansa-Technical-Training.com

www.Lufthansa-Technical-Training.com



 The date given in the column ”Revision” on the face of The date given in the column ”Revision” on the face of

this cover is binding for the complete Training Manual.



 Dates and author’s ID, which may be given at the baseDates and author’s ID, which may be given at the base

of the individual pages, are for

of the individual pages, are for information about theinformation about the

latest revision of that page(s) only.



 The LTT production process ensures that the TrainingThe LTT production process ensures that the Training

Manual contains a complete set of

Manual contains a complete set of all necessary pagesall necessary pages

in the latest finalized revision.

Revision Identification:

(4)

F F O O R R T T R R A A I I N N I I N N G G P P U U R R P P O O S S E E S S O O N N L L Y Y ! !

ICE AND RAIN PROTECTION

L L u u f f t t h h a a n n s s a a T T e e c c h h n n i i c c a a l l T T r r a a i i n n i i n n g g

(5)

F F O O R R T T R R A A I I N N I I N N G G P P U U R R P P O O S S E E S S O O N N L L Y Y ! !

INTRODUCTION & ICE DETECTION

INTRODUCTION

This module will show you how modern aircraft are protected against the This module will show you how modern aircraft are protected against the negative effects of ice and rain.

negative effects of ice and rain.

When an aircraft operates in rain, for instance during takeoff or approach, the When an aircraft operates in rain, for instance during takeoff or approach, the visibility for the pilots is reduced.

visibility for the pilots is reduced. T

To solve this problem we have 2 o solve this problem we have 2 systems in the aircraft:systems in the aircraft:

 A windshield wiper for each pil A windshield wiper for each pilot andot and

a rain repellent system.a rain repellent system.

When the aircraft flies in icing conditions, you can imagine that more problems When the aircraft flies in icing conditions, you can imagine that more problems are possible.

are possible.

An ice buildup on the aircraft mainly has the

An ice buildup on the aircraft mainly has the following effects:following effects:

The aerodynamic quality of the aircraft is reduced andThe aerodynamic quality of the aircraft is reduced and

its weight increases.its weight increases.

The engines can also get problems and the ice can block the probes for The engines can also get problems and the ice can block the probes for the airthe air data system.

data system.

In addition ice on the windshields will decrease the visibility more than rain. In addition ice on the windshields will decrease the visibility more than rain. Before we show you the equipment which prevents these negative effects on Before we show you the equipment which prevents these negative effects on the aircraft, we will look at some general things about ice.

the aircraft, we will look at some general things about ice. L L u u f f t t h h a a n n s s a a T T e e c c h h n n

(6)

F O R T R A I N I N G P U R P O S E S O N L Y !

ICE AND RAIN PROTECTION

INTRODUCTION & ICE DETECTION

FUNDAMENTALS

ATA 30

L u f t h a n s a T e c h n i c a l T r a i n i n g

(7)

WING ANTI-ICE

Usually, clouds have no ice but have supercooled water droplets.

When these droplets hit the aircraft they change from liquid water to solid ice. If the temperature of the droplets is between zero and minus 10°C clear−ice is

produced on the surface.

The ice−build up begins on the leading edge of the surface. This is the hit point where the droplets hit the surface.

Not all of the droplets freeze immediately and therefore some move aft on the surface. This results in a clear ice layer which becomes larger and thicker the longer you fly in these conditions.

L u f t h a n s a T e c h n

(8)

ICE AND RAIN PROTECTION

INTRODUCTION & ICE DETECTION

FUNDAMENTALS

ATA 30

(9)

wing anti-ice cont.

If the temperature of the droplets is below minus 10°C, mainly rime−ice is

produced on the surface.

Again, the ice−build−up begins on the leading edge of the surface where the droplets hit the surface.

But these very cold droplets freeze immediately and build up a rime ice layer on the leading edge only.

When you fly at high speed in this condition, the rime ice layer forms a typical double horn shape.

Both types of ice can also occur together and therefore produce a combination of all negative effects.

Decrease of lift,

increase of weight

and increase of drag.

You have seen that the effect of ice on the aircraft is always negative and can even become dangerous. It must therefore be prevented by either not flying in icing conditions or by the use of an anti −ice system or de-icing system. In jet aircraft, the anti ice system heats the wing leading edge where the ice−build−up begins. It uses warm air from the engines and is therefore named thermal wing anti-ice system.

(10)

ICE AND RAIN PROTECTION

INTRODUCTION & ICE DETECTION

FUNDAMENTALS

ATA 30

(11)

ENGINE ANTI-ICE

In addition to the negative effect on aerodynamics and a higher weight, the engines can also get problems when there is an ice build−up.

Ice has 2 important negative effects on the engine inlet. These are:

A disturbed air flow that reduces the performance of the engine and can lead to a compressor stall and if the engine sucks in pieces of ice, these pieces can damage fan blades or inlet vanes.

To prevent ice build−up on the engine inlet, all jet engines have a thermal anti-ice system.

If an aircraft has a center engine as shown here, you must make sure that ice pieces from the fuselage do not hit the engine.

Usually the antennas get this ice build−up and therefore they are also heated by warm air. L u f t h a n s a T e c h n

(12)

ICE AND RAIN PROTECTION

INTRODUCTION & ICE DETECTION

FUNDAMENTALS

ATA 30

(13)

AIR FOIL DE-ICING

In propeller− driven aircraft not enough hot air for thermal anti-icing is available. Therefore they use an airfoil de−icing system instead.

This system usually uses de−icing rubber boots at the leading edges of the wing and the stabilizers, which normally have the shape of the leading edge structure .

If an ice layer has built up the pilot must activate the de−Icing system which inflates the rubber boots for a short time by pressurized air. This will crack the ice layer and the ice pieces will be blown away by the airstream. To receive a sufficient de−icing effect the pilots have to wait until a certain thickness of the ice layer is reached before the system is switched on.

Usually the rubber boot inflation is rythmically repeated, to get a clean surface. To prevent icing problems of the propulsion, propeller driven aircraft use an engine inlet de-icing system, which usually uses hot air from the engine. The propeller de−icing system is usually heated by electric current. L u f t h a n s a T e c h n

(14)

ICE AND RAIN PROTECTION

INTRODUCTION & ICE DETECTION

FUNDAMENTALS

ATA 30

(15)

GROUND OPERATION

The thermal anti-ice and the de−icing systems are very effective during flight but what do you think happens when snow or ice falls on the aircraft when it is on the ground, for instance over night?

Anti-ice systems prevent ice−build−up on critical aircraft areas during flight. You cannot use them to de−ice an aircraft which has ice already on it and a

de-icing system is only approved for the operation during flight.

Therefore you must perform the de−icing shortly before takeoff with a de−icing fluid. Always follow company procedures.

Allow an aircraft to fly only, when it is free of ice and snow. L u f t h a n s a T e c h n

(16)

ICE AND RAIN PROTECTION

INTRODUCTION & ICE DETECTION

FUNDAMENTALS

ATA 30

(17)

OPTICAL ICE DETECTOR

The thermal anti−ice systems can only do their task when they are switched on before any ice builds up during flight.

On the other hand, it is not permitted to keep the systems on all of the time. This is because taking hot air from the engines reduces their performance and economy.

This means that the pilot must get accurate information when the aircraft flies into icing conditions. This is the task of an ice detector.

Here you see an ice detector of an Airbus aircraft. You find it between the 2 windscreens where it is in sight of both pilots.

When the pilots see ice on this detector, then there is probably ice on other parts of the aircraft. Therefore, the pilots must switch on the thermal anti-ice systems.

This is performed manually by pressing the corresponding push buttons on the overhead panel. L u f t h a n s a T e c h n

(18)

ICE AND RAIN PROTECTION

INTRODUCTION & ICE DETECTION

FUNDAMENTALS

ATA 30

(19)

ELECTRONIC ICE DETECTOR

Now we look at a different type of ice detector.

It is installed near the air data probes and therefore is not visible to the pilots.When this component detects ice, it generates a message in the cockpit and can automatically activate the thermal anti−ice systems.

Some propeller driven aircraft also use this type of ice detector to help the pilot to activate the de−icing system at the correct time.

(20)

ICE AND RAIN PROTECTION

INTRODUCTION & ICE DETECTION

FUNDAMENTALS

ATA 30

(21)

ELECTRICAL ICE DETECTOR

In addition to the previously shown anti ice and de −icing systems, aircraft also have very important electrical anti ice systems.

A probe heat system prevents blockage of air data probes, a window heat system prevents ice on the windshield that would reduce visibility and a line and drain mast heat system prevents frozen water−lines.

All these electrical anti−ice systems are actived during the whole flight. They are partially switched off on the ground to prevent overheat.

(22)

ICE AND RAIN PROTECTION

INTRODUCTION & ICE DETECTION

FUNDAMENTALS

ATA 30

(23)

THERMAL ANTI-ICE SYSTEM

INTRODUCTION

Two thermal anti−ice systems are installed in jet aircraft:

The wing and

the engine anti−ice systems.

The wing anti−ice system uses hot air from the pneumatic system.

One or two valves in each wing, named the wing anti −ice valves, connect the wing anti−ice ducts to the pneumatic system.

The engine anti−ice system also uses hot air. The air comes from either the pneumatic system or directly from the engine. An engine anti−ice valve provides the connection.

When an anti−ice valve opens, the hot air enters the anti−ice duct.

The hot air sprays through small holes in the anti−ice duct into the wing leading edge or engine cowling.

The hot air heats up the area of the leading edge and prevents ice build −up. Later, the air leaves this area through openings in the lower part of the structure.

Extreme caution is necessary during ground tests of thermal anti −ice systems because the air is still hot.

(24)

ICE AND RAIN PROTECTION

THERMAL ANTI - ICE SYSTEMS

FUNDAMENTALS

ATA 30

(25)

F O R T R A I N I N G P U R P O S E S O N L Y ! Introduction cont.

When the wing leading edge is equipped with slats then a telescoping duct is necessary to supply the wing anti−ice duct.

The telescoping duct is short when the slats are retracted and long when the slats are extended.

(26)

ICE AND RAIN PROTECTION

THERMAL ANTI - ICE SYSTEMS

FUNDAMENTALS

ATA 30

(27)

SYSTEM CONTROL

We will now see what it looks like with the two thermal anti −ice systems added. The left and right wing anti−ice system use hot air which is already regulated by the bleed valve.

The engine anti−ice system uses bleed air from the corresponding engine. This air comes either from the engine bleed−air system, upstream of the bleed valve, or from a separate port on the engine compressor.

You can control the thermal anti−ice systems with switches on the overhead panel. Here you see the push buttons in an Airbus aircraft.

The wing anti−ice system always has only one switch. This switch controls the two sides at the same time because the system must always operate

symmetrically.

On engine anti−ice systems you find a switch for each engine installed on the aircraft. L u f t h a n s a T e c h n

(28)

ICE AND RAIN PROTECTION

THERMAL ANTI - ICE SYSTEMS

FUNDAMENTALS

ATA 30

(29)

ELECTRICAL ANTI-ICE SYSTEMS

INTRODUCTION

(30)

ICE AND RAIN PROTECTION

ELECTRICAL ANTI-ICE SYSTEMS

FUNDAMENTALS

ATA 30

(31)

DRAIN MAST HEAT SYSTEM

The drain mast heat system prevents freezing of the waste water outlets on the lower part of the fuselage.

The system is switched on automatically, when electrical power is on.

In drain mast heat systems you find nearly all types of power and temperature control circuits.

You can also find identical circuits for the heating of water pipes in the non heated fuselage areas.

(32)

ICE AND RAIN PROTECTION

ELECTRICAL ANTI-ICE SYSTEMS

FUNDAMENTALS

ATA 30

(33)

PROBE HEAT SYSTEM

A very important anti−ice system for flight safety is the air data probe heating. You can find 4 different types of probes on the aircraft:

the temperature probe, also named rosemount probe, measures air temperature for various calculations

the pitot tubes measure the dynamic air pressure to calculate for example, the airspeed

the static ports measure the static air −pressure to calculate, for example, the altitude

and the angle of attack or alpha sensors which are mainly needed for the stall warning and flight control systems.

The probe heat system is switched on automatically, when you start one of the engines.

You can also switch on the system manually from the control panel if there is a failure in the automatic circuit or for ground tests.

The probe heat system has no temperature control circuits.

The heating power is controlled only in some circuits by the air−ground switching.

If there is a failure in the probe heating during flight, you can get unreliable information from the probes. This can be very dangerous.

Therefore, you get a message on the display of the central warning system, when the heating current is too low.

(34)

ICE AND RAIN PROTECTION

ELECTRICAL ANTI-ICE SYSTEMS

FUNDAMENTALS

ATA 30

(35)

WINDOW HEAT SYSTEM

You can find window heat systems on all aircraft.

Each cockpit window has its own temperature control circuit. The main components of a window heat system are:

the window itself,

the temperature control

and monitoring circuits.

These usually use a window heat control computer which is located in the electric compartment and a system control circuit with an automatic and manual operation. L u f t h a n s a T e c h n

(36)

ICE AND RAIN PROTECTION

ELECTRICAL ANTI-ICE SYSTEMS

FUNDAMENTALS

ATA 30

(37)

RAIN REMOVAL SYSTEMS

RAIN REPELLENT

In this lesson we will show you the systems that are used to improve the visibility for the pilots, when the aircraft operates in rain.

You can find 2 different types of rain removal system in the aircraft. One type removes the water from the windshield mechanically, this is the windshield wiper.

The other system repels the water from the windshields by use of a rain repellent fluid or a special windshield coating.

To repel water from glass the contact angle between the water droplets and the glass is important.

On normal glass the contact angle is about 20°. This results in the water

droplets remaining on the windshield and gives poor visibility.

When you increase the angle to more than 60°, it is not easy for water droplets

to remain on the windshield. This means that they are blown away by the airstream or easily removed by the windshield wiper.

By using rain repellent fluid, you get a high contact angle between water droplets and glass of more than 80°.

This fluid is stored under pressure in a container in the cockpit.

You spray the fluid onto the windshield when you press the corresponding control push−button on the overhead panel. This opens a valve for a short time.

You also can find a hydrophobic coating of the windshield instead of a rain repellent system. With this coating you can increase the contact angle between water and glass up to about 100°.

This system needs no pilot action to operate. Also no maintenance action is necessary as long as the repellent effect of the coating is sufficient. Re−application of the coating onto the windshield is possible. You do it, if for instance, the pilot complains about poor visibility.

To get a long lifetime from this coating, you must do proper windshield cleaning procedures. You must also make correct adjustments of the windshield wipers. L u f t h a n s a T e c h n

(38)

ICE AND RAIN PROTECTION

RAIN REMOVAL SYSTEMS

FUNDAMENTALS

ATA 30

(39)

WINDSHIELD WIPER

A second rain removal system which is on all aircraft is the windshield wiper system.

Each pilot controls his or her own windshield wiper with the corresponding switch on the overhead panel.

The windshield wiper has 2 different speeds.

Slow speed is used during normal rain or during taxi on the ground. When you switch the wiper to off, the wiper arm moves to the park position. This park position is outside the normal wiper area. In some aircraft the wiper blade is also lifted from the windshield to prevent dirt collecting on the wiper blade.

You must never switch on the windshield wiper when the windshield is dry. This will make scratches on the glass layer and will also damage the windshield coating.

Also, the wiper must not be switched on at airspeeds higher than about 250kts. Here the dynamic pressure of the air is too high and can damage the wiper. L u f t h a n s a T e c h n

(40)

ICE AND RAIN PROTECTION

RAIN REMOVAL SYSTEMS

FUNDAMENTALS

ATA 30

(41)

(42)

ICE

AND

RAIN

PROTECTION

. . . .

1

INTRODUCTION & ICE DETECTION. . . 2

INTRODUCTION . . . 2

WINGANTI-ICE . . . 4

ENGINEANTI-ICE . . . 8

AIR FOIL DE-ICING . . . 10

GROUNDOPERATION. . . 12

OPTICAL ICE DETECTOR. . . 14

ELECTRONIC ICE DETECTOR . . . 16

ELECTRICAL ICE DETECTOR . . . 18

THERMAL ANTI-ICE SYSTEM . . . 20

SYSTEMCONTROL . . . 24

ELECTRICAL ANTI-ICE SYSTEMS. . . 26

DRAIN MAST HEAT SYSTEM . . . 28

PROBEHEATSYSTEM . . . 30

WINDOW HEAT SYSTEM . . . 32

RAINREMOVALSYSTEMS. . . 34

RAINREPELLENT. . . 34

(43)

(44)

TABLE OF FIGURES

EJ M11.12 A E

Figure 1 Negative Effects of Ice and Rain. . . 3

Figure 2 Ice Build-up on Wing Leading Edge . . . 5

Figure 3 RimeIceLayer . . . 7

Figure 4 Effects of Ice on Engine Inlet . . . 9

Figure 5 Air Foil De-Icing . . . 11

Figure 6 Ground Operation . . . 13

Figure 7 Optical Ice Detector. . . 15

Figure 8 Electronic Ice Detector . . . 17

Figure 9 Electrical Ice Detection . . . 19

Figure 10 Wing and Engine Anti-Ice Systems. . . 21

Figure 11 Anti-Ice Telescopic Ducts . . . 23

Figure 12 Anti-Ice System Schematic . . . 25

Figure 13 Results of Ice on Aircraft . . . 27

Figure 14 Drain Mast Heat System. . . 29

Figure 15 Probe Heat System . . . 31

Figure 16 Window Heat System . . . 33

Figure 17 Rain Removal Systems. . . 35

(45)

(46)