Embraer Brakes and Reversers

7/30/2019 Embraer Brakes and Reversers

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Agenda Day 2

09:00 - 10:30 System Issues

10:30 - 11:00 Tea Break11:00 - 12:00 Landing on Contaminated Runways

12:00 - 12:30 Procedures and Techniques

12:35 - 13:50 Lunch

14:00 - 15:00 CNS/ATM

15:00 - 15:30 FDM Guidance

15:30 - 16:00 Tea Break

16:00 - 17:00 Considerations on Brakes and

Reversers usage

17:00 - 17:30 Declaring an Emergency


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THIS INFORMATION IS EMBRAER PROPERTY AND CANNOT BE USED OR REPRODUCED WITHOUT WRITTEN AUTHORIZATION.

Considerations on Brakes and Reversers usage

Agenda

Introduction

Some facts

Some numbers

Case studies

Final considerations


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Agenda

Introduction

Some facts

Some numbers

Case studies



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Introduction

Usually, landing deceleration and takeoff

stop performance do not take into account

the use of thrust reversers (T/R)

The T/Rs are a kind of bonus available for

increased safety margins

On the other hand, carbon brakes are veryefficient and work better under some specific

conditions

T/R and Brakes operating policies may varya lot from an operator to another...


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So, whats the best option???

Should T/Rs be used on all landings?

Or should they be used only on restricted/contaminated runways?

How can I save my carbon brakes?

Can I combine Autobrake with T/Rs?


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Agenda

Introduction

Some facts

Some numbers

Case studies



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Facts about reversers

T/Rs are more effective at high speeds; the use of

reverses below 60 kt increases the chances of

foreign object ingestion by the engine

Thrust reversers are stopping devices which do not

depend on runway condition

On slippery runways, thrust reversers may be themost effective way to stop the airplane

Costs of T/Rs usage are difficult to be determined

as T/R maintenance is usually part of particular

agreements with the engine manufacturer


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Facts about carbon brakes

Brake wear is far more related to the

number of applications than to the energy

applied

Braking performance can be optimized by

applying maximum continuous pressure on

the brake pedals. The ANTI-SKID system

will modulate the brakes if required

so keeping pedals pressed and

modulating the pressure is a good

technique for minimizing the brake wear.

Pedals should not be pumped!!!


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Facts about carbon brakes (Cont.)

Test results show that the average

temperature where the brakes wear is

minimized is around 200C

Carbon brakes wear faster when they are

cool

Costs of brakes usage are (also) difficultto be determined due to particularagreements with the brakes supplier


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Facts about performance...

The Autobrake system works aiming a deceleration target:

a) LO mode: - 4 ft/s2

b) MED mode: - 8 ft/s2

c) HI mode: -13 ft/s2.

Brakes applied as required to reach target deceleration level

Deceleration is affected by three factors:

Aerodynamic drag

Wheel brakes

Reverse thrust


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Facts about performance (Cont.)...

In a few words, if the braking coefficient is good, the thrust reversers will not help the

landing performance

Time

Deceleration

Total Deceleration

Brakes Deceleration

Reversers Deceleration

Autobrake Target


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but, if the braking coefficient is NOT good, the thrust reversers could help achieve themaximum deceleration

Total Deceleration

Brakes Deceleration

Reversers Deceleration

Autobrake Target

Time

Deceleration


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Effect of Thrust Reversers on Landing DistanceE190 97000lb Sea Level ISA-2

0

2

4

6

8

10

Dry Std Water

1/8

Std Water

1/2

Slush 1/8 Slush 1/2 Compacted

Snow

Ice

Contaminant Type

LandingDistanceR

eduction(%) MAN

HI

MEDLO



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Agenda

Introduction

Some facts

Some numbers

Case studies



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EJETS - SCHEDULED REMOVALS RATE L12M

BRAKE ISSUES

0,000

0,050

0,100

0,150

0,200

0,250

0,300

J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D

2007 2008 2009

Rate

per100

S.F


Carbon Brakes Assembly Replacement

Reason (Worn to limits, damaged, inoperative, leakage, cycle limit, etc.)

E-Jets - Brake Removals


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MLG Tire / Wheel Assembly Replacement

Reason (Worn to limits, damaged, time limit, etc.)

EJETS - SCHEDULED REMOVALS RATE L12M

TIRE AND WHEEL ISSUES

0,000

0,500

1,000

1,500

2,000

2,500

3,000

3,500

J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D

2007 2008 2009

Rateper100S.F

E-Jets - Wheel and Tire Removals


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So what??

On the previous plots there is no clear correlation between brake wear and wheel/tire

replacements...

therefore, best practices for saving brakes do not necessarily mean that there will be more

wear on wheels and tires!

As an estimated reference, a 500 cycles increase in brakes life represents a reduction of

about 6 USD/FC on brakes cost (i.e about USD 12000 savings considering a 2000 cyclesper acft/yr average utilization)

Using T/R for 15 seconds per flight would increase fuel consumption by about 20lbs per

landing (i.e. about USD 10000 acft/yr if reverse is used on all landings considering a 2000cycles per acft/yr average utilization and fuel @ USD 2/Gal)


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Agenda

Introduction

Some facts

Some numbers

Case studies



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Case studies

Plot was created based on a set of worldwide operators (Americas, Europe, Middle East and

Asia Pacific)

Operators were asked about their policies for (auto)brakes and T/Rs utilization

Environmental conditions and severe winter do have an effect on brakes life...

...but most of all, good practices do make the difference!


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Case studies

Reverse is used on all landings

TRs are always opened but reversethrust is used only on short, wet or

contaminated runways

Reverse usage is as required but on

normal landings reverse thrust is limited

to idle reverse. TRs are mandatory on

contaminated runways

Brake wear reduction policies are

adopted and spread between pilots.

Rational utilization of TRs and(auto)brakes during landings, taxi and

parking procedures.


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Agenda

Introduction

Some facts

Some numbers

Case studies



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What have we seen so far

...on Brakes:

Carbon brakes wear is more a function of the number of applications rather than the amountof braking used so its not a good idea to pump the pedals

Carbon brakes can withstand higher temperatures without loss of efficiency or fading

Brakes wear is greater when they are cool, so special attention should be paid to taxi-out

procedures

Maximum carbon brake life can be achieved during taxi by using a small number of long,

moderately firm brake applications instead of numerous light brake applications

Releasing the parking brake after confirmation that the

chocks are in place is a good idea as this expedites the

cool-down time.


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and on Reversers

If the autobrake is set to LO, reversers should not be used as the system will disengage

brakes anytime the target deceleration is sensed

Whenever the airplane braking coefficient is good and autobrakes are used (any setting),

the T/Rs will not improve the landing performance

For expected braking coefficient medium or poor, the use of thrust reversers couldincrease the airplane deceleration, decreasing the landing distance

The T/R should only be used when the pilots judgment says to do so, according to theairplane speed, weight, weather conditions, etc.


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Remember our initial questions???

Should T/Rs be used on all landings?

Or should they be used only on restricted/contaminated runways?

How can I save my carbon brakes?

Can I combine Autobrake with T/Rs?

Now we should be able to get them answered

and don`t forget


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Safety and passenger comfort come first!


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THANK YOU!

Embraer Brakes and Reversers

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