Technical Support Report
Aircraft Emission Factors
March, 1977
By Robert G. Pace
Notice
Technical support reports for regulatory action do not necessarily
represent the final EPA decision on regulatory issues. They are intended
to present a technical analysis of an issue and conclusions and/or
recommendations resulting from the assumptions and constraints of that
analysis. Agency policy constraints or data received subsequent to the
date of release of this report may alter the conclusions reached.
Readers are cautioned to seek the latest analysis from EPA before using
the information contained herein.
Standards Development and Support Branch
Emission Control Technology Division
Office of Mobile Source Air Pollution Control
Office of Air and Waste Management
U.S. Environmental Protection Agency
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Abstract
Modal emission factors have been calculated for a number of gas
turbine and piston aircraft engines. Emission factors per aircraft per
landing takeoff cycle have been calculated for representative aircraft-
engine combinations. This group includes commercial jet transports,
business j-ets, turboprops and general aviation piston aircraft.
Project Manager
Branch Chief/
Standard Development ami Support Branch
'I Division Director
Emission Control Technology Division
V/
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Introduction
In order to perform useful air quality analysis it is necessary to have
the most accurate emission factor data available. The purpose of this
report is to provide updated aircraft engine emission factors and a
sample of the calculation methodology used in obtaining these numbers.
Two types of data will be presented for each engine studied, modal
emission factors (pounds pollutant per hour at each operating mode) and
emission factors per aircraft landing-'takeoff cycle (total pounds pollu-
tant per LTD).
Both of these types of data are based on the landing and takeoff cycle.
A landing-takeoff (LTD) cycle includes all normal operational modes
performed by an aircraft between the time it descends through an altitude
of 3,500 feet (1,100 meters) on its approach and the time to the 3,500
foot (1,100 meters) altitude after takeoff. The LTO cycle incorporates
the ground operations of idle, taxi, landing run, and takeoff run and
the flight operations of takeoff and climbout to 3,500 feet (1,100
meters) and approach from 3,500 feet (1,100 meters) to touchdown. Each
class of aircraft has its own typical LTO cycle. In order to determine
emissions, the LTO cycle is separated into five distinct modes (1) taxi-
idle-out, (2) takeoff, (3) climbout, (4) approach and landing, and (5)
taxi-idle-in. Each of these modes has its share of time in the LTO.
Table 1 shows typical operating time in each mode for various types of
aircraft classes during periods of heavy activity at a large metropolitan
airport.
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Modal Emission Factors
In Table 2 a set of modal emission factors by engine type are given for
carbon monoxide, total hydrocarbons and nitrogen oxides along with the
fuel flow rate per engine for each LTD mode. With this data and know-
ledge of the time in mode, it is possible to construct any LTO cycle or
mo-de and calculate a more accurate estimate of emissions for the situa-
tion that exists at a specific airport. This capability is especially
important for estimating emissions during the taxi-idle mode when large
amounts of carbon monoxide and hydrocarbons are emitted. At smaller
commercial airports the taxi-idle^time will be less than at the larger,
more congested airports.
i
See Appendix A for sample modal emission factor calcualtions.
Emission Factor Per Aircraft Per Landing Takeoff Cycle
In Table 3 a set of emission factors by aircraft-engine combinations are
given for carbon monoxide, total hydrocarbons, and nitrogen oxides. The
aircraft-engine combination were choosen by selecting a typical aircraft
for which engine emission data was available. The emission factor
presented represents the total pounds of pollutant emitted by each
aircraft per landing-takeoff cycle. Thus, for multiengine aircraft the
emission factors include the sum of pollutants from each engine.
See Appendix B for sample calculations.
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TABLE 2 - MODAL EMISSION FACTORS
-------
Gas Turbines
EnRlne and Mode
General Electric
CF700-2D
Idle
Takeoff
Cllmbout
Approach
General Electric
CF6-6D
Idle
Takeoff
Cllmbout
Approach
\
General Electric
cro-soc
Idle
Takeoff
Cllrabcut
Approach
Pratt 6 Whitney
JT3D-7
Idle
Takeoff
Climbout
Approach
Fuel Rate
LB.
'HR
/i 60
2607
2322
919
1063
13750
11329
3864
1206
L8900
L5622
5280
1013
9956
8188
3084
KG.
'lIR
208.7
1182
1053
416. 9
482.2
6237
5139
1753
547
8573
7104
2395
459.5
4516
3714
1399
Carbon Monoxide
LB.
'HR
71.30
57.35
58.05
56.98
65.06
8.25
6.80-
23.18
88.04
.38
4.70
22.70
140.8
8.96
15.56
60.14
KG
'HR
32.34
26.01
26.33
25.85
29.51
3.74
3.03
10.51
39.93
.172
2.13
10.30
63.87
4.06
7. Ob
27.28
Hydrocarbons
•LB.
'HR
8.28
.26
.23
1,29
21.79
8.25
6.80
6.96
36.18
.19
.16
.05
124.6
4.98
3.28
6.48
KG/
'HR
3.76
.118
.104
.585
9.88
3.74
3.08
3.16
16.41
.086
.073
.023
56.52
2.26
1.49
2.94
Nitrogen Oxides
(N0x as N02)
LB
'HR
.41
14.60
9.98
1.65
4.88
467.5
309.2
41.54
3.02
670.95
462.0
52.8
2.23
126.4
78.6
16.35
KG
'HR
.186
6.62
4.53
.748
2.21
212.1
140.2
18,84
1.37
304.3
209.6
23.95
1.01
57.34
35.65
7,42
T.ible 2 - Modal emission Factors ( gas Lurhancs )
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Engine und Mode
Prate & Whitney
JT8D-17
Idle
Takeoff
CUmbout
Approach
Vratt & Whitney
JT9D-7
Idle
Tjkeoft
Climbout
Approach
Pratt & Whitney
JT9D-70
Idle
Takeoff
Climbout
Approach
Rolls Royce
Spey 555
Idle
Takeoff
Climbout
Approach
-- - _ . ... ,
Fuel Rate
LB.
'lIR
1150
9980
7910
2810
1849
16142
13193
4648
1800
19380
15980
5850
755
5516
4501
1655
KG.
'HR
521.6
4527
3538
1275
838.7
7322
5984
2108
816.5
6791
7248
2654
J42.5
2502
2041
750.7
Carbon Monoxide
LB.
'HR
39.10
6.99
7.91
20.23
142.4
3.23
6.60
44.62
61.20
3.88
4.79
7.61
36.77
28.11
38.71
41.71
KG
'HR
17.74
3.17
3.59
9.18
64.59
1.47
2.99
20.24
/
27.76
1.76
2.17
3.45
16.68
12.76
17.56
18.92
Hydrocarbons
LB.
'HR
10.10
.50
.40
1.41
55.10
.81
1.32
4.65
12.24
2.91
2.40
2.63
9.51
14.89
16.20
8.28
KG.
'HR
4.58
.227
.181
.640
24.99
.367
.599
2.11
,.55
1.32
1.09
1.19
4.31
6.75
7.35
3.76
Nitrogen Oxides
(N0x as N02)
LB.
'HR
3.91
202.6
123.4
19.39
5.73
474.6
282.3
36.25
5,76
600.8
386.7
47.39
.83
80.53
50.41
6.95
KG
'HR
1.77
91.90
55 97
8.80
2.60
215.3
123.0
16.44
2.61
272.5
175.4
21.50
.376
36.53
22.87
3.15 '
Table 2 - Modal Emission Factors ( gas turbines )
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Engine and Mode
Pratt & Whitney
Aircraft of Canada
JT15D-1
Idle
Takeoff
Climbout
Approac
Pratt & Whitney
Aircraft of Canada
PT6A-27
Idle
Takrqff
Climbout
Approach
Prutt & Whitney
Aircraft of Canada
PI6A-41
Idle
Takeoff
Climbout
Approach
General Motors
Allison 250B17B
I.Jlc
Takeoff
Climbout
Approach
General Motors
Allison 501C22A
IdU
Takeoff
Climbout
Approach
Fuel Rate
LB.
'HR
215
1405
1247
481
115
425
400
215
147
510
473
273
63
Zo5
245
1 85
610
2576
2198
1140
KG.
'HR
97.52
637.3
565.6
218.2
52.16
192.8
181.4
97.52
66.68
231 3
214.6
123.8
28.58
120.2
lll.l
38.56
276.7
1078
997
517.1
Carbon Monoxide
LB,
'HR
19.46
1.41
1.25
11.45
7.36
.43
48
4.95
16.95
2.60
3.07
9.50
6.13
2.07
J.ii
4.13
26.60
4.85
4.53
5.81
LB.
'HR
8.83
.640
.567
5.19
3.34
.195
.218
2.24
(
7.69 '
1.18
1.39
A. 31
2.78
.939
1.00
1.87
12.07
2.20
2.05
2.64
Hydrocarbons
LB
'HR
i
7.48
0
0
1.59
5.77
0
0
.47
14.94
.89
.96
6.20
1.27
.07
.0$
.44
10.74
.67
1.96
2.23
KG
'HR
3.39
0
0
.721
2.62
0
0
.213
6.78
.404
.435
2.81
.576
.032
.041
.200
4.87
.304
.889
1.01
Nitrogen Oxldea
(N0x as N02)
LB.
'HR
.54
14.19
11.35
2.45
.28
3.32
2.80
1.80
.29
4.07
3.58
1.27
.09
1.75
1.46
.19
2.15
21.10
20.27
8.54
KG
'HR
.245
6.44
5.15
l.ll
.127
1.51
1.27
.816
.132
1.85
1.62
.576
.041
.794
.662
.086
.975
9T57
9.19
5757
Table 2 - Modal Emission Factors ( gas turbines )
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General Aviation
Piston
Engine and Mode
Avco/Lycomlnc
IO-320-D1A1J
Tail-Idle
Takeoff
Cllmbnut
Approach
Avco/LycotnlnR
10-360-B
Taxi-Idle
Takeoff
Climbout
Approach
Avco/Lycomlng
TIO-540-J2D2
Taxi-Idle
Takeoff
Climbout
Approach
Taxi- Idle
Takeoff
Climbout
Approach
Fuel Rate
LB.
'HR
"•.84
iU.67
61 42
37.67
8 09
103.0
71.7
36.6
25.06
259.7
204.5
99.4
KG
'HR
3.56
41.57
27.85
17.08
3.68
46.7
32.5
16.6
11.36
117.8
92.7
45.1
Carbon Monoxide
LB.
'HR
4.86
109.3
54.55
35.57
7.26
123.5
70.5
25.3
32.42
374.5
300.8
125.4
KG
'HR
2.20
49.55
24.74
16.13
1
t
~ t
3.29
56.0
32.0
11.5
14.70
169.8
136.4
56.9
LB;
'HR
.283
1.047
.588
.460
.398
1.03
.585
.355
1.706
3.21
3.40
1.33
KG
'HR
.128
.475
.267
.208
.180
.469
.265
.161
.774
1.46
1.54
.604
Nitrogen Oxides
(NO an NO.)
LB.
'HR
.009
.167
.344
.128
.0094
.205
.329
.372
.0097
.094
.0481
.138
KG.
'HR
.0041
.075f»
.156
.058
.0042
.093
.149
.169
.0044
.043
.0218
.0623
Table 2 - Modal Emission Factors ( general aviation piston )
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Table 3 - EMISSION FACTORS PER AIRCRAFT PER L.T.O. CYCLE
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Representative
Aircraft
Commercial Jets
Boeing
747-200B
Boeing
747-200B
McDonnell
Douglas
DC10-30
Boeing
707-320B
Boeing
727-200
Boeing
737-200
McDonnell
Douglas
DC7 Series 50
Mi.DonnPl 1
Douglas
DCS
Engine Model and
Manufacturer
Pratt & Whitney
JT9D-7
Pratt & Whitney
JT9D-70
General Electric
CF6-50C
Pratt & Whitney
JT3D-7
Pratt and Whitney
JT8D-17
Pratt & Whitney
JT8D-17
Pratt i Whitney
JT8D-17
Pratt & Whitney
JT3D-7
Engines Per
Aircraft
4
4
3
4
3
2
2
4
Emission Factors
Carbon Monoxide
LB KG
259.64
108.92
116.88
262.64
55.95
37.30
37.30
262.64
117.76
49.40
53.01
119.12
25.38
16.92
16.92
119.12
Per Aircraft Per Landlne
Hydrocarbons
LB KG
96.92
22.40
47.10
t
l
218.24
13.44
8.96
8.96
218.24
43.96
10.16
21. J6
99.00
6.09
4.06
4.06
99.00
-Takeoff Cycle
Nitrogen Oxides
LB KG
83.24
107.48
49.59
25.63
29.64
19.^6
19.76
25.68
37.76
48.76
22.17
11.64
13.44
8.9b
8. '16
11.64
Table 3a - Commercial Jets
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Representative
Aircraft
Business Jets
Cessna
Citation
I.earjet
240
Lcarjet
35. 36
Rockwell
Internationa).
Sabre 75A
Engine Model and
Manufacturer
Pratt & Whitney
JT15D-1
General Electric
CJ610-6
Garret t AiResearch
TFE 731-2
General Electric
CE CF700
Engines Per
Aircraft
2
2
2
2
*•
'Emission Factors
Carbon Monoxide
LB KG
9.10
41.22
5.39
35.67
4.41
18.70
2.44
16.18
Per Aircraft Per Land inn
Hydrocarbons
LB KG
3.32
4.14
1
li'84
3.66
1.51
1.88
.834
1.66
-Takeoff Cycle
Nitrogen Oxides
LB KG
.742
.588
1.22
.626
.336
.266
.553
.284
Table 3b - Business Jets
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Representative
AJrcraft
Business
Turlioprops
Beech
B99
Airliner
dcllavllland
Twin Ottnr
Shorts
Skyvan-3
Svcaringen
Merlin IIIA
Engine Model and
Manufacturer
United Aircraft
of Canada
PTCA-27
United Aircraft
of Canada
PfGA-27
Carrett
TPE 331-2
farrett
TPE 331-3
Engines Per
Aircraft
2
2
2
2
Emission Factors
Carbon Monoxide
LB KG
7.16
7.16
6.44
6.28
3.25
3.25
2.92
2.85
Per Aircraft Per Land in a
Hydrocarbons
LB KG
5.08
f
/5.08
8.40
7.71
2.30
2.30
3.81
3.50
-Takeoff Cycla
Nitrogen Oxides
LB KG
.687
.687
.883
1.15
.312
.312
.400
.522
Table 3d - Business Turboprops
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Appendix A
Sample Modal Emission Factors Calculation
1) Gas Turbines
The data used in calculating gas turbine modal emission factors were
taken from Reference 1. Referring to Reference 1, we have the following
data for the Pratt & Whitney JT9D-7 gas turbine.
Ibs. pollutant..
noae ruex TJ.OW \,xos/nr^ emission inaex V-i/-).-.,-. iv f — T
Idle
Approach
Climbout
Takeoff
1849
4648
13193
16142
1 HC
29.8
1.0
0.1
0.05
CO
77.0
9.6
0.5
0.2
NOx
3.1
7.8
21.4
29.4
To obtain the modal emission rates perform the following calculation.
Emission Index x Fuel Flow = Modal Emission Rate
For the idle mode the above methods give the following values for
unburned hydrocarbons.
70
29'
lbs> HC
1000 Ibs. fuel
ini-)r
1849(
lba>
hr.
=c , /
55tl(
. HC.
hr
Similar methods are used for the other modes and pollutants.
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Appendix B
Sample Calculations for Emission Factors per Aircraft per Landing
Takeoff Cycle
To calculate emission factors per aircraft per landing takeoff cycle
take a representative aireraft-engine combination, use the appropriate
modal emission factors from table 2 and multiply by a typical time in
mode from table 1.
As an example use the Cessna Citation powered by 2 Pratt & Whitney
JT15D-1 gas turbine engines. This is a typical in-use business jet.
Table 1 gaves the following time in modes for this type of aircraft.
Mode Time (min)
Taxi-idle 13.0
Takeoff 0.40
Climbout 0.50
Approach 1.60
From Table 2 take the following data.
Mode CO (#/hr) HC (///hr) NOx (///hr)
Taxi-idle
Takeoff
Climbout
Approach
19.46
1.41
1.25
11.45
7.48
0
0
1.59
0.54
14.19
11.35
2.45
Using this data perform the following calculation (using CO as an example)
-L ci i ic. ji /T- xx 1.60 min \
+ 111.45 ff/hrM—————) = 4.54 Ibs. CO per aircraft engine
60 min/hr , ,. *. , cc •>
per landing takeoff cycle
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This aircraft uses two engine, therefore;
2 x 4.54 Ibs. CO - 9.08 Ibs. CO
The number is the total number of pounds of carbon monoxide emitted by this
aircraft for the landing takeoff cycle used. Similar calculations are
performed for HC and NOx.
-------
References
1. EPA, Aircraft Technology Assessment, Status Of The Gas Turbine
Program, December 1976.
2. Avco-Lycoming, Exhaust Emission Survey of a Piston Aircraft Engine,
Avco-Lycoming IO-320-D1AD, S/N 886-X.
3. Avco-Lycoming, Exhaust Emission Survey of a Piston Aircraft Engine,
Avco-Lycoming IO-360-B1BD, S/N 887-X.
4. Avco-Lycoming, Twenty-Fourth Monthly Progress Report, Contract No.
DOT-FA74NA-1092, Communication Report No. 311-24, August 10, 1976.
5. Teledyne Continental Motors, Engineering Report #26 (August 1976
Reporting Period).
6. Teledyne Continental Mo tors-,* ^Report No. TCM 5204, Exhaust Emission
Studies of Piston Aircraft Engine TSIO-360-C, S/N 300244, September 1975,
7. Teledyne Continental Motors,' Report No. TCM 5205, Exhaust Emission
Studies of Piston Aircraft Engine Tiara 6-285-B, S/N 700106,
April 1976.
8. Avco-Lycoming, Exhaust Emission Survey of a Piston Aircraft Engine,
Avco-Lycoming 0320-D1AD, S/N 886-X.
9. Teledyne Continental Motors, Report No. TCM 5202, Exhaust Emission
Studies of Piston Aircraft Engine IO-520-D, S/N 559025, June 1975.
10. Teledyne Continental Motors, Report No. TCM 5207, Exhaust Emission
Studies of Piston Aircraft Engine GTSIO-520-K, S/N 220015, October 1976.
11. Nature and Control of Aircraft Engine Exhaust Emissions. Northern
Research and Engineering Corporation, Cambridge, Mass. Prepared
for National Air Pollution Control Administration, Durham N.C. under
Contract Number PH22-68-27, November 1968.
12. The Potential Impact of Aircraft Emissions upon Air Quality.
Northern Research and Engineering Corporation, Cambridge, Mass.
Prepared for the Environmental Protection Agency, Research Triangle
Park, N.C., under Contract Number 68-02-0085, December 1971.
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