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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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Considerations on Brakes and Reversers usage
Agenda
Introduction
Some facts
Some numbers
Case studies
Final considerations
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Considerations on Brakes and Reversers usage
Agenda
Introduction
Some facts
Some numbers
Case studies
Final considerations
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Considerations on Brakes and Reversers usage
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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Considerations on Brakes and Reversers usage
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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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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Considerations on Brakes and Reversers usage
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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Considerations on Brakes and Reversers usage
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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Considerations on Brakes and Reversers usage
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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Considerations on Brakes and Reversers usage
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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Considerations on Brakes and Reversers usage
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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Considerations on Brakes and Reversers usage
Facts about performance (Cont.)...
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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Considerations on Brakes and Reversers usage
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
Facts about performance (Cont.)...
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Considerations on Brakes and Reversers usage
Agenda
Introduction
Some facts
Some numbers
Case studies
Final considerations
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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
Considerations on Brakes and Reversers usage
Carbon Brakes Assembly Replacement
Reason (Worn to limits, damaged, inoperative, leakage, cycle limit, etc.)
E-Jets - Brake Removals
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Considerations on Brakes and Reversers usage
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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Considerations on Brakes and Reversers usage
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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Considerations on Brakes and Reversers usage
Agenda
Introduction
Some facts
Some numbers
Case studies
Final considerations
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Considerations on Brakes and Reversers usage
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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Considerations on Brakes and Reversers usage
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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Considerations on Brakes and Reversers usage
Agenda
Introduction
Some facts
Some numbers
Case studies
Final considerations
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Considerations on Brakes and Reversers usage
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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Considerations on Brakes and Reversers usage
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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Considerations on Brakes and Reversers usage
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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Considerations on Brakes and Reversers usage
Safety and passenger comfort come first!
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THANK YOU!