ATR: The Optimum Choice for a Friendly Environment - Modern Transport and Environment
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Modern Transport and Environment
ATR:
The Optimum
Choice
for a Friendly
Environment
Foreword
The purpose of this
brochure is to
illustrate ways in
which the regional
air transport can
contribute to Today’s regional airliner is
minimize its a high technology, fuel
environmental efficient and quiet
impact. aircraft, purpose-built for
the regional market and
environmentally friendly
either in terms of noise or
gazeous emission levels, even when compared to
other forms of transport.
Modern regional turboprops and namely ATR aircraft
meet both external noise and gazeous emission level
regulatory requirements with ample margins.
ATR’s short field capability, their optimum integration
in air traffic flow, and their cumulative noise level
margins to the latest regulations or airport
restrictions, make them welcome visitors at the Modern air transport & environment
smaller city airports and regional hubs with minimal Summary
environmental impact.
The regional aircraft: good neighbours
ATR turboprop aircraft, recognized as the most fuel ATR for a quieter environment
efficient aircraft in their category, maintain
distinctive advantages with respect to other modes ATR for a cleaner environment
of transport such as road and rail , also in terms of Time to change public, corporate and political
pollutant emissions. perceptions
To reconcile the increasing need for mobility Appendices
and the demands of environmental protection, the - Appendix 1: Environmental ABCs
key idea is to join the different modes of transport - Appendix 2: References & abbreviations
into an integrated system, the intermodality.
Each mode of transport has its specific strengths; the
objective is to combine them to minimize fuel
consumption and environmental impact, creating
also decisive advantage for users.
But, in order to develop a fair, integrated and
competitive Europe-wide transport system, no single
transport mode should have an advantage over
another.
Legislation which has an adverse impact on airline
profitability could lead to postponements of further
investment in more environmentally acceptable
aircraft.
Regional aircraft and turboprop in particular can
justify their view that they are already respecters of
the environment and good neighbours for Airlines
and airport communities.
CO/EM 467/00 - June 2001
Modern Air Transport & Environment 1
Summary
The aviation industry has grown rapidly and has Infrastructure improvements
become an integral and vital part of modern society. The accelerated introduction of communications,
The air transport industry plays a major role in world navigation, surveillance and air traffic management
economic activity. (CNS/ATM) systems and additional infrastructure
- Over 1,600 million passengers per year rely on the could enable airlines to fly the shortest distances
world’s airlines for business and vacation travel. and reduce fuel consumption.
- Around 40% of the world’s manufactured exports, Improvements in air traffic management could
by value, are transported by air. reduce fuel burn per trip by 6%-12% for today’s
- More than 3.9 million people are directly employed global fleet (IPCC Report - 1999).
by the industry throughout the world.
Source: ATAG, ERA
Future projections suggest that demand for air travel
will continue to rise, in line with the growth in the
Environmental emissions
world economy. By 2010 the number of people
travelling by air could exceed 2.3 billion each year.
This has created concern that aviation’s rapid 3%
expansion will outstrip improvements in industry
environmental performance. 6%
Aviation is by necessity an efficient industry.
Efficiency is an essential first step on the road to
sustainability and this is the key to minimising 25%
aviation’s environmental impact.
Compared to other means of transport, aviation
54%
has an enviable environmental record, but this is
still too much a well-kept secret!
Energy consumption 12%
Aviation consumes about 12% of the oil supplies Air
used by the entire transport industry. Industry
Aircraft being produced today are about 70% more Energy
fuel efficient per pax/km than those of 40 years ago. Other transport
Road
Emissions
Today, aviation is responsible for less than 3% of A recent Swedish Road and Traffic Research Institute
world annual additions to greenhouse gases and less study to measure emission levels, comparing
than 3% of the production of nitrous oxide-type gas. different transport modes with industry and energy,
revealed that only 3% was attributable to air
transport.
Climate change
Aircraft emissions contribute an estimated 3.5% to
the overall climate effects resulting from all man- Sources of pollutant emissions
made activities.
70%
Land use
Land use is at a premium (specially in Europe) and 60%
aviation is unique in transport modes in that, unlike 50%
rail and car use, it only requires land use at the
40%
point of departure and destination and not from
point to point. 30%
20%
10%
0
Airlines Road Other Energy Industry
transport
Oxides of nitrogen
Hydrocarbons
Source: SAS
Carbon monoxide
Modern Air Transport & Environment 2
Summary
Fuel efficiency Airline fuel consumption reductions
Airlines have doubled their fuel efficiency over the indexed to 1976
last 30 years. Further improvements in efficiency are 100
expected to reduce emissions growth to 3% a year
compared to a forecast growth of 5% in traffic.
80
Noise
Fleet renewal based on the use of improved
technology has significantly reduced total noise
60
exposure around airports despite the cumulative
market growth.
Aircraft entering the fleet today are typically 20 dB
quieter than comparable aircraft of 30 years ago, 40
which in practice corresponds to a reduction in noise
76 78
annoyance of about 75% (Source: ATAG - Air Transport 80 82 84
Action Group). 86 88 90
Air transport contributes only 1% to the nuisances 92 94
superior to 65 dBA at which 80 million people of
European Union are exposed (road transport In the past 30 years aircraft fuel efficiency per
contributes 90%). passenger-km has improved by about 50% through
enhancements in airframe design, engine technology
and rising load factors.
Source: ICAO, Boeing
Noise Exposure to more than 65 dBA
2 Boeing 737-200 Airbus A319
1
Rail transport Air transport
1.7% 1% 2
Other sources
(industries, working 1
parties)
7.3% 2 0 2 4 6 8 10
85 dB(A) noise footprint at take-off (in km)
Road transport
90%
Source: Airbus/Lufthansa
Rail and Air Transport Noise Exposure
People exposed to more than 65 dBA
European Union
80 million people of European Union’s population are
exposed to continuous day-time outdoor noise levels
caused by transport above what are generally considered to
be acceptable, more than 65 dB(A).
Air transport
An additional 170 million citizens are exposed to noise
levels between 55-65 dB(A) which is the level at which 37% Rail transport
people become seriously annoyed during the day time.
63%
Road transport is the dominant source accounting for
nine tenths of the proportion of the European Union’s
population exposed to levels of noise over 65 dB(A).
As for rail, 1.7% of the population and air transport a
further 1% of the population are exposed to these high
levels.
Sources : European Commission "Green
Paper” - 1995
Modern Air Transport & Environment 3
The regional aircraft: good neighbours
Regional aircraft have low impact “upon Comparative noise footprints - 90 EPNdB
neighbours” and meet all the statutory noise The benefits of the new technology
(Chapter III) and emission level requirements
enabling them to be accepted at the smaller city Area sq miles
Modern regional turboprop
airports and regional hubs with minimal (sq km)
environmental impact. 1.2 (3.5)
Both turboprop and turbofan aircraft use exactly Modern regional jet
the same jet technology maximizing efficiency and
reliability. 2.1 (5.4)
30-year old turboprop
Turboprop/Jet: The same concept 5.2 (13.5)
30-year old jet
11.3 (29.3)
40,000 20,000 0 20,000 40,000 60,000
Gas turbine
Distance from Distance from
threshold (ft) start of roll (ft)
Fleet renewal, based on the use of newer, quieter aircraft
and noise abatement operating measures has significantly
reduced the number of people affected by aircraft noise.
Movement comes from The
Movement mainly comes The turboprop
turboprop is is more
more fuel
fuel efficient
efficient
the large quantity of air from the air forced for
for aa given
given thrust.
thrust.
forced backwards at low backwards at high speed
speed by the propellers
European Regional Airlines
Fleet age breakdown
The average age of the ERA (European Number of 100
Regional Airlines) members’ fleet is just aircraft
90
eight years and the airlines and the 80
manufacturers are continuously investing 70
in the latest technology in order to
60
minimise the impact of their equipment
and their operations on the environment.
50
50% of
40 ERA fleet
30 is less
than 7
20 years old
10
0
0 1 2 3 4 5 6 7 8 9 10 11 12 15 20 25 >25
Source: ERA Yearbook 2001
Aircraft age Aircraft age
Source : OAG, October 1995
Total
Total ERA
ERA fleet
fleet :: 1200+
1200+ aircraft
aircraft -- Percentage
Percentage turboprop
turboprop :: 55%
55%
Number
Number of of ATR
ATR 4242 &
& ATR
ATR 72 72 in
in service
service inin ERA
ERA fleet
fleet :: 170
170
40/70
40/70 seater
seater turboprop
turboprop in
in the
the ERA
ERA fleet
fleet :: 480
480 -- ATR
ATR percentage
percentage in in this
this segment
segment :: 35%
35%
Average
Average age age ofof total
total fleet
fleet :: 88 years
years
Modern Air Transport & Environment 4
The regional aircraft: good neighbours
Low fuel consumption Low exhaust Silence, please! 2000 ft
emissions Approach noise levels
EPNdB
The only method of significantly reducing emissions
of H2O and CO2 is by reducing fuel burn, mainly Compared with older, larger
jets which may have 102
driven by the use of adapted aircraft size and 86-90
coloured people’s
optimised load factors on a given route and by perception of aircraft 1000 ft 78-87
reductions in air traffic management delays. noise, regional
aircraft are very 104
Emissions of NOx (Nitrogen oxides) by regional quiet. To some 92-96
extent noise is 87-92
aircraft are at low altitudes, well below the levels at
which ozone depletion is a major concern. “seen”
by the
public.
Congestion remains
air transport’s biggest
long term challenge.
It causes delays and
unreliability for
passengers, reduced
efficiency for airline Take-off noise levels
and airport operators, EPNdB
and a massive waste For example, one take-off by
of energy and a B727 is equivalent to over
100 take-offs by a typical 2000 ft
materials.
regional aircraft in terms
of decibels.
Congestion means that aircraft are required to
operate at lower and inefficient cruising levels. The In many cases, regional
aircraft noise will be
extra fuel required can mean an aircraft burns N/a
contained within the 86
between 20% and 30% additional fuel on each trip. airfield boundary.
1000 ft 78
In the initial climb
Advanced turboprop operate more efficiently than phase and on approach
jet aircraft on short-haul routes. many regional 98
93
They emit about 20% less CO2 per passenger-Km aircraft generate 85
than newer jets and up to three times less CO2 than noise barely
older ones. perceptible
against 102
Source: ATAG (Air Transport Action Group).
ambient 83
noise 81
levels.
Noise measurement
of electric passenger train
Aircraft cause noise disturbance in the
vicinity of airports and mainly during day
time, thereby limiting noise disturbance.
High speed trains, however, operating 24
hours per day, create noise disturbance
over the entire length of their 7.5m
journey and not just
at the rail station.
95-100 EPNdB
Large airliner Typical regional jet Typical modern
turboprop
Source: “E.C. Green Paper on future noise policy”. Measured at
ICE train, 250 km/h, 7.5m from the railway, peak level.
Modern Air Transport & Environment 5
ATR for a quieter environment
General
ICAO (International Civil Aviation Organization) has
defined three main categories of permitted noise
levels for commercial aircraft, Chapters I, II, and
III.
All Chapter I aircraft, the noisiest types, have
already been withdrawn from service and Chapter
II will be phased out in April 2002.
In 1996 over 91% of aircraft in Europe were
of Chapter 3 standard.
The limits for Chapter III aircraft, which are the
quietest available, are extremely stringent. Even
so, the industry is working with the regulators to
issue more restrictive limits.
The Committee on Aviation Environmental
Protection (CAEP5) of the ICAO meeting in Montreal ATR: Quiet neighbours
in mid-January 2001, issued a series of The latest propulsion technology combined with good
recommendations aimed at reducing aircraft noise. aerodynamic design make ATR aircraft quiet neighbours,
Specific CAEP5 recommendations include: meeting stage IV noise requirements with wide margins,
hence reducing at minimum its environmental impact.
A new noise standard (Chapter IV) which is
The -500 series in particular are setting new standards in
10 decibels lower, on a cumulative basis, than the the industry for quietness. This allows day and night
current Chapter III standards in Annex 16 to the operations on platforms with specific, stringent local noise
ICAO, for new aircraft design, effective 1st January regulations such as city airports.
2006;
Procedures for re-certification of existing a/c
meeting the new standard;
More stringent noise standards for helicopters;
Publication of guidance material on land-use
planning;
A proposal for new take-off noise abatement
procedures.
ICAO
ICAO Chapter
Chapter IV
IV Rules
Rules
ATR
ATR family
family compliance
compliance
ICAO
ICAO “CAEP
“CAEP 5”
5” held
held in
in Montreal
Montreal from
from the
the 8th
8th to
to 17th
17th of
of January
January 2001
2001 -- Chapter
Chapter IV
IV
Applicable
Applicable by
by 1st
1st of
of January
January 2006
2006 for
for certification
certification of
of new
new types
types (new
(new oror derivative
derivative aircraft);
aircraft);
Chapter
Chapter IVIV =
= Chapter
Chapter IIIIII -- 10
10 cumulative
cumulative EPNdB;
EPNdB; whatever
whatever two
two or
or three
three measurement
measurement points
points must
must
have
have not
not less
less than
than 22 EPNdB
EPNdB cumulative
cumulative margin;
margin; implementation
implementation of of the
the re-certification
re-certification concept;
concept;
Not
Not yet
yet intended
intended toto bebe used
used forfor any
any general
general new
new operational
operational restrictions
restrictions such
such as
as phase
phase out;
out;
Possible
Possible request
request ofof local
local authorities
authorities toto quickly
quickly achieve
achieve the
the Chapter
Chapter IVIV ticket
ticket for
for current
current Ch.
Ch. III
III aircraft.
aircraft.
All
All ATR
ATR models
models comply
comply with
with Chapter
Chapter IV
IV requirements
requirements with
with large
large margins.
margins.
Modern Air Transport & Environment 6ATR for a quieter environment
dBA
100
Noise from turboprop aircraft during take-off comes Different Noise Sources
essentially from the propeller. dBA levels
During approach other noise sources such as jet 95
thrust, noise coming from compressors and turbine
and aerodynamics of the aircraft contribute to the
nuisances. 90
ATR family has been designed to obtain the
maximum exterior noise reduction and minimum
85
environmental impact, by:
A high thrust to weight ratio in order to have the
steepest take-off path, reducing noise footprint 80
High technology propeller system installed on -
500 series reducing dramatically noise emissions
Decreasing the propeller rotational speed and 75
optimizing the blade profile Lorry Intercity ATR 42-500 ATR 72-500 High speed
Well aerodynamically designed high-lift system. 50 km/h train take-off take-off train
7.5 m 200 km/h 100 m from 100 m from 300 km/h
from road 7.5 m runway runway 100 m from
from railway railway
ATR for a quieter environment Sources : Economic Commission "Green Paper" - ATR - Aviation
Noise relative to ICAO Chapter III (EPNdB) International News
0
The external noise standards applicable to the ATR42
-2 and ATR72 are laid down in :
-4 FAR part 36 Chapter III for the Federal Aviation
Administration
-6 Chapter III of Annex 16 to the Convention of
Chicago on International Civil Aviation for the ICAO
-8
ATR -500 series: large
-10 margins versus current
and future noise
-12 regulations or more
stringent airport
restrictions
-14
Sideline Take-off Approach Max T.O. weight
ATR 42-500
PW 127E
ATR 72-500
PW 127F
Source: ATR Take-off
ine reference
el e
Sid renc
e 0m )
ref 45 NM
4
2
(0.
)
NM
51
Design (3.
m
00
landing weight 65
3˚
Approach m
reference 00
20 NM
) The ICAO and FAA regulations define
(1.
0 8 flight procedures and noise
measurement point locations.
Modern Air Transport & Environment 7ATR for a quieter environment
ATR -500 Series Noise Levels - Certified Figures
Point
Point of
of ICAO
ICAO and
and FAR
FAR 36
36 ATR
ATR 42-500
42-500 ATR
ATR 72-500
72-500
measurement
measurement Certified
Certified levels
levels Certified
Certified levels
levels
EPNdB
EPNdB EPNdB
EPNdB EPNdB
EPNdB
Chapter
Chapter III
III limits
limits MTOW
MTOW 18,600
18,600 kg
kg MTOW
MTOW 22,000
22,000 kg
kg
Take-off
Take-off 89
89 76.6
76.6 79
79
Sideline
Sideline 94
94 80.7
80.7 83.2
83.2
Approach
Approach 98
98 92.4
92.4 92.2
92.2
EPNd B NdB
Global
Global 281
281 249.7 -31.3
249.7 254.4 -26.6 EP
254.4
Chapter
Chapter IV
IV limits
limits (future)
(future) 271
271 -21.3
-21.3 -16.6
-16.6
Source: ATR
New New
generation generation
ATR family, more and more ATR ATR ATR ATR ATR ATR ATR
42-300 42-320 42-400 42-500 72-200 72-210 72-500
environment friendly EPNdB
Cumulative noise margin
0
(EPNdB)
With 26.6 EPNdB (ATR 72-500)
and 31.3 EPNdB (ATR 42-500)
-5
cumulative margin to Chapter III,
and comfortable margins to -10
future Chapter IV noise
regulation, the ATR-500 series -15
has the greatest latitude for even
more stringent regulations on -20
EIS
airport restrictions. EIS 1989
1985
-25 Qu
Qu iet
ie er
All
All ATR
ATR models
models will
will comply
comply with
with -30 te
even
even the
the most
most stringent
stringent stage
stage r EIS 1997
IV
EIS 1995
IV noise
noise recommendations.
recommendations. -35
EIS: Entry into Service Source: ATR
Total perceived noise on flyover,
sideline and approach (EPNdB)
300
Regional Air Transport F28 Mk4000
The benefits of technology for 290
external noise
280 HS 748 F 27 Mk500
F 27 H RJ85
270 CRJ 700
F100 (prelim.)
F50 DHC 8-300 ERJ 145
260
ATP Do 328 DHC 8Q-400
DHC 7
250 Saab 340 CRJ 200 ATR
ATR 72-500
72-500
ATR
ATR -500
-500 series:
series: the
the quietest
quietest
neighbours
Saab 2000 ATR
ATR 42-500
42-500
neighbours inin the
the sky!
sky!
240
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
Year of introduction
Source : ERA (European Regional Airline Association)
Modern Air Transport & Environment 8ATR for a quieter environment
Low external noise levels make the ATR 42/72 welcome visitors to several urban airports worldwide: travellers
increasingly recognize the numerous advantages of flying through smaller, uncongested airports close to big
city centers.
All over the world, and especially in Europe, Noise Footprint: 90 EPNdB Contours
airport and Airworthiness Authorities are ATR 72/Fokker 100
taking action against excessive aircraft noise
and emissions.
If not compliant with environmental
regulations, airlines have to pay additional
airport taxes (noise/emissions surcharges) or
are submitted to operational restrictions.
6000 4000 2000 0 -2000 -4000
Thanks to the high technology 568F propeller
system and efficient aerodynamics, the ATR- Distance from start of take-off roll (m)
500 series is one of the quietest in the
industry. Source: ATR
Take-off
Take-off Approach
Approach Total
Total
Fokker
Fokker 100
100 4.33
4.33 km²
km² 1.07
1.07 km²
km² 5.40
5.40 km²
km²
ATR
ATR 72
72 2.05
2.05 km²
km² 1.45
1.45 km²
km² 3.50
3.50 km²
km²
Modern Air Transport & Environment 9ATR for a cleaner environment
Average emissions per year by aircraft age
Gaseous emissions: the Legal Frame
Grams/pax
A new focus of attention regarding aircraft
emissions was introduced in 1992, with the 180
emergence of environmental problems of a global 160
nature to which aircraft emissions may be 140
contributing, such as climate change, depletion of
120
ozone layer, and long-range air pollution.
100
In June 1992, in Rio de Janeiro, a Convention 80
was signed by 170 countries at the U.N. Conference
60
on Environment and Climate Change, with the
40
objective of stabilizing greenhouse gas
concentrations at a safe level within an acceptable 20
time frame. 0
The Kyoto Protocol to this Convention was adopted
in 1997 with the objective of reducing collective Hydrocarbons CO NOx
emissions of greenhouse gases by approximately Old Medium New
5% by the period 2008-2012, with respect to 1990
Source: Rolls Royce
levels.
Compliance with Kyoto Target
Kyoto’s key elements at a glance
CO2 index (index = 100 in year 1990) Industrialised countries to cut net emissions of a
300
Traffic growth ‘basket’ of six greenhouses gases by an average of
at least 5% below 1990 level by 2008-2012;
250 EU and most accession countries to cut emissions
Fleet renewal by 8%; US by 7%; Japan and Canada by 6%; Russia
to stabilise emissions;
200 Basket of gases covers carbon dioxide, methane,
A/C size nitrous oxide and three fluorinated industrial gases -
HFCs, PFCs and sulfur hexafluoride.
ATM
150 By 2005, industrialised countries are required to
Trading/charge show demonstrable progress towards achieving their
Kyoto target
emission targets;
100
1990 1994 1998 2002 2006 2010 Trading of emissions rights, and investments in
foreign projects generating emission credits, are
A combination of actions will be required to compensate air allowed between industrialised countries as a
traffic growth and meet the Kyoto target for CO2 emissions. supplement to domestic action to limi emissions;
Source: SNECMA
Clean Development Fund to be set up to promote
sustainable development in developping countries
and help industrialised nations reduce compliance
>
> June
June 1992
1992 Convention
Convention on
on environment
environment and
and climate
climate costs through investment in emission-reduction
change
change signed
signed by
by 170
170 countries
countries projects in the developping world: these investments
in
in Rio
Rio de
de Janeiro
Janeiro generate certified emission reductions for the
investing country;
>> 1997
1997 Protocol
Protocol ofof Kyoto
Kyoto Greenhouse gas emission from, or absorbtion by,
> Objective
> Objective certain direct human-induced forestry and land-use
-- at
at least
least 5%
5% reduction
reduction of
of six
six Green
Green House
House Gas
Gas (GHG)
(GHG) activities since 1990 are to be counted when
emission
emission by by industrialised
industrialised countries
countries during
during the
the period
period assessing whether countries comply with their
2008-2012
2008-2012 with with respect
respect to
to 1990
1990 levels,
levels, with
with the
the target
target emission targets.
varying
varying from
from country
country toto country.
country.
The aviation industry has made great strides Airlines
Airlines taking
taking action
action
over the years to improve the fuel efficiency of Responsible
Responsible airlines
airlines are
are facing
facing up
up toto the
the challenges,
challenges,
aircraft engines. Improvements in engines have implementing
implementing environmentally-friendly
environmentally-friendly measures,
measures,
resulted in much lower levels of emissions of ranging
ranging from
from taxiing
taxiing onon one
one engine,
engine, collecting
collecting rainwater
rainwater
to
to wash
wash aircraft
aircraft and
and recycling
recycling inflight
inflight food
food trays,
trays, to
to
Carbon Monoxide (CO) and Unburned Hydrocarbons
renewing
renewing fleets
fleets with
with more
more energy-efficient
energy-efficient aircraft
aircraft and
and
(UHC). However, the higher combustion optimizing
optimizing approach
approach andand departure
departure routings.
routings.
temperatures achieved tend to push up the levels Lufthansa,
Lufthansa, for
for example,
example, has has adopted
adopted longlong term
term targets
targets
of oxides of nitrogen (NOx), as shown in the reflected
reflected by
by Kyoto
Kyoto to to cut
cut specific
specific fuel
fuel consumption
consumption by by
following figure. 30%
30% byby 2008,
2008, andand byby 35%
35% by by 2012.
2012.
Modern Air Transport & Environment 10ATR for a cleaner environment
Main gaseous emissions Emissions and Energy Usage
Typical emissions of a modern aeroengine
Water Carbon Dioxide
Aircraft affect the atmosphere by introducing gases
(CO2) 71%
and particles into it and by forming contrails. 28%
The emissions include greenhouse gases such as
carbon dioxide (CO2) and water vapor, as well as
chemically active gases that alter natural
greenhouse gases, such as nitrogen oxides (NOx)
and carbon monoxide (CO). Particles (Unburned
Hydrocarbons, UHC), may interact with the earth’s
radiation balance or influence the formation of
clouds.
Water emissions by aircraft engines lead directly to
the formation of contrails that are characteristics of Carbon dioxide - Carbon Monoxide
high-flying aircraft in cruise. Water
- Nitrogen Oxide
- Sulphur Dioxide
There is a concern that contrails may have a - Unburnt Hydrocarbons
disproportionate effect on global warming. Source: ATAG - Soot
Each
Each year
year civil
civil aviation
aviation is
is responsible
responsible
for
for approximately
approximately 2.4%2.4% ofof the
the world’s
world’s
total
total CO
CO22 production.
production.
As is now well known, CO2, a natural by-product of
combustion, contributes to climate change via the
so-called greenhouse effect. To be true, other
emissions are also involved, among them Nox,
water vapour and smoke, the latter via contrails.
1 kg of kerosene
contains...
3.15 kg carbon
dioxide
Reaction In low quantities, carbon
with oxygen monoxide is a natural
component of air; at higher
concentrations it contributes
to the green house effect and
thus to global warming.
1.24 kg
1 kg water
Source: CFM
kerosene vapour
Key environment impact issues associated with aircraft engine emissions
Emission Category Impact
Smoke Visibility nuisance around airports
Unburned hydrocarbons (UHC) Contribution to urban smog burdens
Carbon monoxide (CO) Contribution to urban CO burdens
Nitrogen oxides (NOx)
- Subsonic aircraft engines Possible contribution to global warming
- Future supersonic aircraft engines Stratospheric ozone depletion
Carbon dioxide (CO2) Contribution to global warming
Modern Air Transport & Environment 11ATR for a cleaner environment
Gaseous emissions: Standards and
Regulations The ICAO emissions regulations are based on a
standard Landing and Take-off Cycle (LTO).
In general there are very few regulations relating to
turboprop emissions.
Aircraft engines are regulated on the amount of LTO Cycle Emissions - ATR 72 with PW124B
emissions they can produce. The main standards
are included in :
Gaseous Landing, take-off cycle
ICAO, Annex 16, Vol. 2, the recommendations Emissions
of which apply only to turbojets and turbofans; CO 2,748 g
FAA (FAR 34), using much of what ICAO has NOx 1,472 g
proposed, but only smoke standards have been UHC 1,132 g
set for turboprop.
The species that are regulated are NOx (Nitrogen Landing Take-Off cycle (LTO)
oxides), CO (Carbon monoxide), UHC (Unburnt
Hydrocarbons) and smoke.
CO UHC NOx SMOKE CO2 H 2O
ICAO Jets only Jets only Jets only Jets only None None
FAA None Jets only None Jets/Tprops None None
ICAO recommendation contained in Annex 16 is
currently in force for jet engines only and concerns
Operating mode Power setting Time in mode
emissions of CO, UHC, NOx and smoke.
1. Taxi/idle 7% take-off thrust 26 min.
The FAA legislation (FAR 34) is significantly less 2. Take-off 100% std day take-off thrust 0.7 min.
demanding although it deals with both turbofan and 3. Climb 85% take-off thrust 2.2 min.
turboprop aircraft. 4. Approach 30% take-off thrust 4.0 min.
With respect to turboprop engines, it is expected
that no stricter legislative measures will be taken Landing, take-off cycle
for the following reasons: Regional turboprops vs large jets
The small contribution of turboprop aircraft to the
total emissions from aviation Gaseous Emissions
9,300 16,000
(g/LTO cycle)
The already considerable progress made in the
reductions of pollutants closely related to energy 5000
consumption, on these gas turbine engines
ATR
ATR42-500
42-500
The favourable operational aspects of these 4000
engine/aircraft combinations: ATR
ATR72-500
72-500
1. Relatively low operating altitudes
2. Relatively short manoeuvring times at airports. 3000 BB737-300
737-300
Modern equipment in use with regional airlines
2000
(50% of the ERA fleet being less than 7 years old).
Current regional air transport (up to 80 seats) 1000
contributes only 10% of the total fuel burn of
European aviation).
0
Emissions take place at low altitudes leading to a UHC NOx CO
very small contribution to pollution and nil to the
depletion of the ozone layer. LTO cycle = ICAO reference
Sources : P & W Canada - ICAO
Modern Air Transport & Environment 12ATR for a cleaner environment
ATR: the green turboprop of tomorrow
The ATR fuel efficiency: adapted
It appears evident that low levels of engine
powerplant emissions are essentially driven by low fuel
consumption.
The proven level of low fuel consumption is a On a 200 Nm sector, the ATR72-500 fuel
primary concern for airlines eager to lower cash consumption per passenger is up to 11% lower than
operating cost. a typical European car; the associated ATR gaseous
ATR aircraft are recognized as the most fuel emissions per pax in terms of CO (Carbon Monoxide)
efficient aircraft in their category, thanks also to are 15 times less than a car and comparable to the
high-tech engines and propeller efficiency. train.
ATR powered by PW100 family engines As far as the nitrous oxides are concerned, the ATR
Main technical characteristics is 3 times less pollutant than a car and 40% less
' Two centrifugal compressors than a train. Moreover emissions of NOx (Nitrogen
' Free turbine, three concentric shafts oxides) by new generation turboprops are at low
' Electronic and hydromechanical regulators altitude, well below the levels at which ozone
' Power range from 2,000 to 2,750 shp depletion is a major concern.
Gaseous Emission Spectrum
200 NM (370 km) typical sector
65% load factor
Car
Turboprop advantages
Best trade-off between fuel burn and speed, 70 Seater
perfectly adapted to commuter requirements, Jet
Simple, economic, easy to maintain,
Low specific fuel consumption,
Compliance with today ’s and future noise level Train*
regulations,
Low gaseous emissions. Tprop Emissions
(ATR 72) g/pax km
Fuel Consumption per passenger 0 1 2 3
200 NM (370 km) stage length
Hydrocarbons Carbon Nitrous
Aircraft with 65% LF
monoxide oxides
27 l
(7.14US gal) * Electricity from heavy fuel power station
18 l
16 l (4.76US gal)
(4.23US gal)
Just for reference, an ATR 42 uses only as
much fuel on a typical 200 Nm trip as a B747
uses in 10 minutes of taxiing!
ATR 72 European car Jet aircraft
72 pax 2 pax 120 pax
ATR 42-300 ATR 42-320 ATR 42-500 ATR 72-200 ATR 72-210 ATR 72-500
Take-off power 1,800 shp 1,900 shp 2,160 shp 2,160 shp 2,475 shp 2,475 shp
Take-off power 2,000 sp 2,100 shp 2,400 shp 2,400 shp 2,750 shp 2,750 shp
(one engine out)
Propeller (Hamilton Std) 14SF-5 14SF-5 568F 14SF-11 247F 568F
Modern Air Transport & Environment 13ATR for a cleaner environment
Reducing pollutant emissions by reducing ATR: optimum integration in air traffic flow
airport congestion
Congestion is a serious and increasing constraint on The ATR aircraft take advantage of their high 250 Kt
the growth of air transport, and inadequate aviation CAS maximum operating speed, which is the max
infrastructure costs the world economy billion of speed allowed by air traffic control below 10,000 feet
dollars in inefficiency. for all aircraft: this facilitates the flow of aircraft
approaching congested airports.
It has been estimated that by 2005 appoximately
33,000 aircraft will be in commercial use, and The most part of ATR aircraft are operated around the
approximately 10 percent of this total will be “hub & spoke” concept, used by Airlines to increase
employed in long-range operations. operating efficiency and to improve passenger
This leaves about 30,000 aircraft that would be in services. This concept helps reducing environmental
service at various route lengths. impact significantly.
Traffic continues to grow and it would appear
that this will go on at a faster rate than the planned
increase in Air Traffic Management.
Unnecessary congestion is caused by the
inefficient use of existing airport facilities, and is a
serious obstruction to free competition.
The cost to Europe’s economy caused by shortfall in
capacity/congestion amounts to 5.4 Bn $ ( 5 Md Hub and spoke
Direct
Euro).
In Europe, delays caused by Air Traffic Control
Hub and spoke concept: Consolidating traffic flows, increased
continue to mar on-time punctuality results, with operating efficiency, same number of markets served with fewer
only 57% of flights departing on time. flights.
In 1999 only, the British Airways fleet burned
27,000 tons of kerosene during the holdings
above London-Heathrow airport.
It has been estimated that 350,000 hours of
flights by transport aircraft are wasted in Europe
annually, due to airport and air traffic management
(ATM) delays and non-optimal routings.
The recent IPCC-report on the global impact of
aviation estimates that ATM improvement can
reduce fuel burn by 6% to 12% within the next 20
years.
A strategy to address such matters includes:
Reducing airport congestion and hence time
spent taxiing and awaiting take-off clearance
Optimised flight profile
Achieving more direct routings than the current
air traffic control environment permits
Reducing ATC delays adopting flight levels to
avoid the upper atmosphere where nitrogen oxide
emissions deplete the earth’s ozone umbrella
against damaging ultraviolet radiation.
Modern Air Transport & Environment 14ATR for a cleaner environment
The emergence of regional jets
Turboprops:
Turboprops: unmatched
unmatched airfield
airfield
These aircraft have a significant impact on Air performance
performance
3,829
3,829 airports
airports in in the
the OAG
OAG data
data
Traffic Management philosophy as they usually fly
Turboprops
Turboprops can can access
access toto 744
744 airports
airports with
with aa runway
runway
relatively short distances at high altitudes.
length
length between
between 1,000
1,000 and
and 1,500
1,500 mm
The end result will be a significant growth in aircraft -- 98
98 in
in the
the US
US -- 93
93 in
in Latin
Latin America
America -- 76
76 in
in Canada
Canada
movements which will speed up the need to create -- 70
70 in
in Europe
Europe -- 110
110 inin Africa
Africa and
and in
in Middle
Middle East
East
additional airspace capacity. -- 116
116 inin Asia
Asia -- 181
181 inin Australasia
Australasia
Regional
Regional jetsjets typically
typically need
need runways
runways of of 1,600m.
1,600m.
Operationally regional jets are the source of big
concerns for ATC system:
Take-off distances regional
With longer take-off and landing rolls than vs larger aircraft
turboprops, RJs often are unable to use the shorter
runways set aside for commuter operations at
Regional aircraft
many airport hubs. With RJs working, all pilots are departure routes
Regional jet Turboprop
thus less likely to accept Land and Hold Short
(LAHSO) clearances, since the small jets cannot, in
most cases, hold short.
Since RJ operators are so closely linked to their
mainline partners, it no longer makes sense for RJs B747 at 500’
B B747 take-off point
to use “commuter terminals” positioned some
distance from the mainline terminals. So RJs now
compete with the big guys for gate space, and their
30- or 50-strong passenger loads have joined the
milling throng inside, raising temperatures.
Source: B&CA (May 2000)
ATR: short field capability 12,000ft 14,000ft
ATR is easily manoeuvrable and features short Turboprop superior performance capability gives them a unique
take-off and landing capability to meet operational advantage in the market place, offering benefits to airports,
operators and most of all the travelling public.
requirements for unrestricted passenger loading.
On a given standard mission, a 50 seater jet
requires about 40% more take-off field length than
the ATR on a typical mission with a full passenger
payload.
Short Field Capability
50-Seater jet vs ATR take-off field length
ATR Regional
Jet
%
+40
Thanks to their excellent landing and take-off
performance, ATR aircraft are able to use the shorter
runways set aside for commuter operations at many
airport hubs.
They contribute in this way to reduce air traffic
congestion, decrease Airline fuel consumption and to
reduce environmental impact.
Turboprops aircraft join and leave runways at a
variety of entry and exit points. They are allowed to
take-off while large aircraft are still manoeuvring at
the end of the runway, and to utilise separate, short
runways.
Modern Air Transport & Environment 15ATR for a cleaner environment
ATR: The optimum choice for a friendly
environment
Regional aircraft are good neighbours for the Some airports have a largely unused crosswind
environment. runway, which many regional aircraft can use, thus
They avoid environmental offence largely by taking them out of the main traffic flow (45 and 38
avoiding excess. They do not fly the largest, the Kts at take-off and landing respectively are the
highest, the fastest, or the greatest numbers. cross-wind limits for ATR42).
Flying empty seats around the sky is not an
Since regional aircraft are only a limited environmentally friendly act. Here again the
proportion of the total world fleet (about 30%), an regionals have some natural advantage. It is easier
even smaller proportion in terms of tonnage on the for a regional to match capacity provided to actual
wing, the regionals contribute a small fraction of passenger number by juggling with frequency and
aircraft attributable emissions. numbers of generally smaller aircraft.
Since regional aircraft operate at relatively low In summary, turboprop aircraft and ATR in
altitude, they leave the ozone layer unaffected and particular can justify their view that they are
contribute little to pollution of the upper already respecters of the environment and
atmosphere. good neighbours for Airlines and airport
communities.
Turboprops are highly efficient and tend to
operate at lower speeds. In recognition of their low
pollutant emission levels, turboprop aircraft remain
unregulated and are not covered by ICAO Annex ATR
ATR stands
stands out
out as
as aa modern,
modern, comfortable
comfortable
16. They also have low OPR (Overall Pressure and
and cost
cost saving
saving regional
regional turboprop
turboprop with
with
Ratio), 10-20:1 as against 20-40:1 for the large the
the particular
particular ecological
ecological advantage
advantage of
of
turbofans, and hence produce much more lower safegarding
safegarding the
the environment.
environment.
NOx levels.
Modern Air Transport & Environment 16Time to change public, corporate and political perceptions
At the intersection of multiples modes of ATR : the clean power of tomorrow
transport
The key word for environmentally compatible Today’s regional airline fleets are characterised by
transport is “Intermodality”, the division of labor modern, technologically advanced turboprops which
between aircraft, car, train and boat. are environment friendly. Increasingly, small jets are
becoming part of the regional scene.
Each mode of transport has its specific strengths;
the objective is to combine the different modes in No longer are the regional fleets dominated by
ways to minimize fuel consumption and unsuitable, noisy, old aircraft handed down by major
environmental impact, creating also decisive carriers, but by new-generation aircraft, purpose-
advantage for the users. built specifically for the regional market.
However, this does nothing to change the basic The use of regional turboprop aircraft has minimal
capacity problems here. Shifting domestic flights to environmental impact since they are the quietest
rail can only create a brief respite for the airport’s available, with very low gaseous emissions level,
urgently necessary expansion. even when compared with other forms of transport
such as cars, buses or trains.
Rail transport plays a major part in Europe’s
transport infrastructure. An efficient rail transport Low drag airframe, efficient aerodynamics, low
system is essential for Europe but il should operate aircraft weight per passenger (or freight) carried and
within the same constraints as air transport. the resulting level of fuel saving have prompted
The development of new high speed lines means many operators to select turboprop and specially ATR
that it is competing more and more with regional air above all others.
transport.
More and more politicians and regulators perceive rail
This notwithstanding, obvious bias towards rail transport as environmentally superior to all other
transport as indicated in recent E.C. documents modes of transport, including air !
(E.C. Communication on Air Transport and Whilst electric trains have theoretically slightly lower
Environment) are highly opinable: emission levels than regional aircraft, due to lower
“ … for many short to medium distance flights, primary energy consumption, they require the
rail in particular high speed rail, can offer a realistic provision of electricity in the first place, which,
alternative.” depending upon its method of production, can itself
“ … This will contribute to replacing shorter flights add serious pollutant to the environment.
by truly competitive rail transport.”
Both statements are part of the European Primary energy
Commission recommendations to limit the growth of consumption
civil air transport in order to reduce its (g/passenger km)
environmental impact. 50
In order to develop a fair, integrated and
competitive Europe-wide transport system, no single 40
transport mode should have an advantage over
another. 30 35
As a matter of fact today in Europe rail transport 28
and particularly high speed train, are expanding 20
very rapidly, better supported by E.C. with respect 21.5
to other means of transport, specially for short
regional connections, being emotionally and 10
erroneously considered not environment friendly.
That is not the case. Constraints or preferential 0
treatment applied to one mode should also be TGV ATR 72-500 Std Typical car
applied to the other. South-East France Cruise FL200 2 passengers
270 km/h 510 km/h 130 km/h
Heavy fuel Jet-fuel Car petrol
65% LF 65% LF
Sources : E.C. - EDF - SNCF - ATR
Modern Air Transport & Environment 17Time to change public, corporate and political perceptions
Environmental
impact Required New Ground Surface
Airport and railway infrastructures
Occupied ground
NOx SO2
surface (ha)
Kg/year Kg/year
2500
?
? ?
? ?
? Infrastructures
to be built
2000
1500
?
1000
Thermic Nuclear 500 Infrastructures
Station Station mostly existing
0
TGV Regional New high
In fact, when comparing air transport to the rail South-East airports speed
transport, two different technologies have to be France Paris-Lyon trains
compared: train-thermic station-heavy fuel 410 km
versus modern turboprop engine-thermo- Sources : SNCF - ATR
dynamic-jet fuel, with a gap of at least 20 years
in their technological development; the results in
terms of pollutant emissions are largely positive for Ground based transportation is essential for local
the air transport. access, but long-distance infrastructure impacts
These facts explain why ICAO do not apply any rule communities, farmlands and wilderness areas. The
to turboprops as far as engine emissions are growth of air transportation has greatly reduced the
concerned. need for new highway and rail corridors.
The graph on this page shows a comparison of land
In addition, the expansion of high speed rail consumption for different modes of transportation,
networks demands the construction of dedicated based on square meters of land per passenger-
tracks, often parallel to existing rails, long kilometer traveled.
implementation, significant financial and ground
surface resources (6 hectares/km) : in clear a huge Regional airports already exist, no
environmental impact of the railways supplementary surface is required.
infrastructures. A new regional fleet is very shortly ready to
fly…
m2/pkm* Land-Use Comparison of Transport Modes
0.008
0.007 While the total land
consumed by airports is
0.006 likely to increase in the
future, the amount of land
0.005 covered by roads is
growing even faster.
0.004
0.003
0.002 * Square meters of land
per passenger-kilometer
0.001 traveled
Source : Infras (1997)
0.000
Passenger Coach Intercity Short-haul Long-haul
car train flight flight
Modern Air Transport & Environment 18Appendices
APPENDIX 1 3. Carbon monoxide (CO)
Chemical compound consisting of one carbon and
Environmental ABC’s one oxygen atom. It forms in the combustion
process, mainly as the result of incomplete
Main definitions and key terms
combustion. For aircraft engines, the level of CO
emissions depends very much on the thrust level :
1. Atmosphere
emissions are high per kilogram of fuel consumed at
The whole mass of air surrounding the earth. It is the idle setting, while taxiing and during approach.
divided into various layers, distinguished from one
They are low during take-off and cruising.
other by distinct differences in temperature.
For air transport , the two lower layers are of
importance: the troposphere, where weather - E.I. CO
related events take place, and the stratosphere, (gms / kgm)
lying above that.
120
In the stratosphere, we find the so-called ozone
Fig. 2
layer at altitudes of about 25 to 30 kilometers.
Today’s commercial aircraft have cruising altitudes 100
of between 10 and 12 Kilometers. As a result,
according to the latest research, air traffic 80
emissions do not have an impact on ozone layer.
60
50km
40
Representative
small engines
20
30km 0
Stratosphere
0 20 40 60 80 100
NOx emissions from supersonic aircraft Idle Approach Climb Take-off
Ozone Layer
Percent engine power
15km
Fig. 1
15km Tropopause
Subsonic jet flight envelope 4. db(A)
Troposphere
Ground level ozone up to 1km Boundary Unit which uses the A-weighting curve. This unit has
layer
become an international standard for noise
measurement especially for road noise. A sound
level meter on the A-weighting curve functions as a
filter discriminating against the lower frequencies in
a manner similar to human hearing. This weighting
2. Carbon dioxide (CO2) curve is widely used for measuring surface noise.
Gas resulting in nature from the burning or
decomposition of organic masses and from the 5. Decibel (dB)
breathing process of humans and animals. Basic unit of noise measurement.
In the atmosphere, CO2 is an important greenhouse To take into account the variation of the sensitivity
gas. of the ear to different frequencies, each of the
Per 1 ton of fuel, 3.15 tons of CO2 result from the frequencies which make up a specific sound is
combustion process. weighted according to international standardised
Currently, 2.4 percent of man made CO2 emissions weighting curves.
are due to air traffic. Climatologists fear that further There are four different weighting curves, named A,
increases in CO2 emissions could lead to a warming B, C, D.
of the atmosphere. CO2 remains in the atmosphere Transportation noise is usually measured according
for about 100 years. to A-curve.
6. Effective Perceived Noise decibel (EPNdB)
Conceived to measure annoyance by jet aircraft
noise. It introduces the duration of the event and a
correction for frequency irregularities.
The EPNdB is the unit of EPNL (effective perceived
noise level) used by FAA and ICAO as the standard
measurement for aircraft certification.
Modern Air Transport & Environment 19Appendices
7. Emission Index (E.I.) 9. Landing & Take-Off cycle (LTO)
The amount of pollutant emitted during each phase The LTO cycle is a theoretical reflection of aircraft
of the LTO (landing, take-off) cycle is calculated by movements at an airport. It only applies in the
means of Emission Indices : the number of pollutant vicinity of airports, is based on engine performance
grams per Kg of fuel burned. and does not take account of airframe factors.
The Emission Indices are measured on an engine in a The LTO cycle was devised to regulate airport air
test bed. quality not cruise emissions, it therefore takes no
account of emissions beyond an altitude of 3,000 ft.
8. Emissions Concern about the global effects of emissions
The combustion of kerosene in an aircraft engine (including cruise) may in time lead to a complete
results above all in carbon dioxide and water vapor. flight cycle definition.
All other emissions together (carbon monoxide, The extraordinarily long taxiing time shown in the
sulphur dioxide, nitrogen oxides, unburned table, is recommended as a consequence of
hydrocarbons) amount to 1-2 percent, depending on congestion at some airports forcing aircraft to wait in
the type of engine and flight phase. a queue for take-off. Since the idle is the least
Carbon dioxide (CO2) and water vapor emissions efficient operating mode of an engine, the LTO cycle
depend on fuel consumption alone; sulphur dioxide emphasizes the production of UHC and CO.
emissions depend on fuel’s sulphur content. All other
components of the exhaust gases can be reduced by
optimizing the combustion process in the engine.
Factors affecting aircraft emissions
CO and UHC are the result of incomplete combustion
Ap
pr
oa
of fossil fuel, which especially takes place at low ch
power setting during airport operations (taxi and 3,000 ft
Cli
mb
idle). Taxi ou
t
On most modern gas turbine engines, CO and UHC 3,000 ft
production is very small at an approach power of Take-o
Tax
i in
30% or above. ff
- CO and UHC increase at low power
- NOx increases at high power ICAO landing/take-off cycle
- Emissions of UHC are at their highest and of NOx at
their lowest when an aircraft is at idle. During take-
off the reverse is true. ICAO LTO Cycle
NOx rate of formation is function of the prevailing Operating Thrust Duration
conditions in the combustion chamber, in particular, conditions level (min)
the temperature of the air coming from the (rated thrust)
compressor. Taxi out 7% 19
Take-off 100% 0.7
E.I. Climb 85% 2.2
(UHC, CO, NOx) Fig. 3 Approach 30% 4.0
Taxi-in 7% 7.0
10. Market based options for emission under
study by ICAO
Smoke Emission-related levies
UHC
NOx
- A fuel tax, with revenue used by government to
CO offset other taxes.
- A revenue neutral charge based on aircraft
Idle Approach Climb Take-off efficiency, with higher charges on less fuel-efficient
0 20 40 60 80 100 Percent engine
power
aircraft offset by lower charges on more fuel efficient
ones.
Percent engine power - An en route emissions charge, with revenues
recycled to the aviation sector (for environment-
enhancing purposes, such as support for early
retirement of aircraft).
- An en-route emissions tax, with revenues being
used to offset other taxes.
Modern Air Transport & Environment 20Appendices
Emissions trading 12. Ozone (O3)
- An open system, in which emissions from all Molecul consisting of three oxygen atoms.
aviation sectors (domestic and international) are Close to the ground it is a component of “summer
treated indentically to other emissions, and trading smog” and irritates the mucous membranes. Fig.In
5 the
may take place between the aviation sectors and stratosphere, ozone absorbs ultraviolet light (ozone
other sectors. layer).
- A closed system, in which international aviation At current levels, nitrogen oxides emissions from
emissions may only be traded within the aviation air traffic at cruising altitudes causes an increase in
sector, with a fixed cap. This would leave domestic atmospheric ozone.
emissions subject to national emissions trading
rules. International emissions would be ring fenced
and treated separately.
- An en-route emissions tax, with revenues being
used to offset other taxes.
Voluntary agreements
- Agreement between industry (airlines and aircraft
manufacturers) and authorities (individual
governments, groups or governements or
international organisations). They would aim for a
specific target for reducing emissions, measured in
grams of CO2 per unit of traffic).
- Hybrid option drawing from elements from each of
the three elements under consideration (levies,
trading and voluntary agreements).
11. Nitrogen oxides (NOx)
Chemical compound consisting of one nitrogen and
several oxygen atoms. Changes in ozone concentration in the atmosphere.
Nitrogen oxides are also generated in combustion Source: Has-Planck Institut für Chemie
processes under high pressures and temperatures.
But both of these parameters have been increased in
modern aircraft engines to significantly reduce fuel
consumption, and emissions of carbon monoxide 13. Stratosphere (fig. 1)
and unburned hydrocarbon. Layer of air above the troposphere, at altitudes of
Combustion chambers of an advanced design could about 12 to 50 Kilometers.
help reduce NOx emissions by 85 percent in the
future. 14. Tropopause (fig. 1)
Air traffic has a share of 2-3 percent of man-made Transition layer between the troposphere and the
NOx emissions. stratosphere.
Climate models show that nitrogen oxidesFig. 4
have
increased the concentration of ozone at cruising 15. Troposphere (fig. 1)
altitudes by a few percentage points. Lowest layer of the earth’s atmosphere and location of
Currently, the effect cannot be measured. weather events. Depending on the season, the upper
boundaries of the troposphere reach altitudes of 6-8
EI NOx kilometers above the poles and 16-18 kilometers in
tropical areas.
100
80 FIRST
GENERATION
MODERN
60 TURBOFANS
40
FUTURE LOW
20 NOx
REGIONAL BIG
0 TURBOPROPS FANS
0 5 10 15 20 25 30 35 40 45
OPR
EI: Emission Index
Many regional aircraft engines have lower NOx EI that can be
anticipated for even the future third generation of large
turbofan engines.
Modern Air Transport & Environment 21Appendices
16. Unburned hydrocarbons (UHC)
Mixture of hydrocarbons that results from incomplete
combustion processes. Near the ground UHCs
contribute to the formation of “summer smog”.
E.I. UHC
(gms / kgm) Fig. 6
120
100
80
60
40
Representative
20 small engines
0
0 20 40 60 80 100
Idle Approach Climb Take-off
Percent engine power
17. Water vapor
Even ahead of carbon dioxide, water vapor is the
most important greenhouse gas.
Concerns that air traffic might increase the
concentration of water vapor in the stratosphere and
thus change the climate have been refuted by
scientific research.
Under certain meteorological conditions, the water
vapor from aircraft engines can lead to the formation
of vapor trails. These may occasionally persist for
several hours. Theoretically, vapor trails influence
the earth’s radiation household by hindering the
reflection of warmth into space.
Modern Air Transport & Environment 22Appendices
PW127F engine gaseous emissions
Mode Power Fuel Emission Index Emission index Emission index
% power Setting Flow CO UHC NOx
SHP kg/min g/kg fuel g/kg fuel g/kg fuel
Min. flight idle (3%) 27 1.58 26.3 3.8 4.5
Min. ground idle 45 1.32 36.6 16.5 4.1
Nominal idle (7%) 192 3.06 9.2 0 6.9
Approach (30%) 825 5.15 3.7 0 9.8
Max cruise (78%) 2,132 8.28 2.2 0 15.6
Max climb (80%) 2,192 8.38 2.0 0 16.2
Max contin. (90%) 2,475 9.22 2.0 0 16.5
Take-off (100%) 2,750 9.9 2.0 0 17.7
Source: PWC Exhaust Emissions Data - March 1997
ATR 72-500 trip pattern 22,000ft
380 km mission 170 KCAS Max cruise 250 KCAS
ISA -5°C
Phase Taxi out Take-off Climb Cruise Descent Approach Taxi in Total
& climb from 3,000ft
to 3,000ft & landing
Fuel (kg) 18 35 218 228 81 19 6 605
Time (min) 6 2.1 16.3 21.2 9.6 2.5 2 59.7
Dist (km) 0 4 105 178 89 4 0 380
TOW=18,500kg - OEW=13,300kg - ZFW= 17,195kg - FAA reserves
LTO Cycle Emissions
ATR 72-500 with PW127F
Gaseous Landing, take-off cycle
Emissions
CO 2,740 g
NOx 1,558 g
UHC 1,128 g
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