Design of a Flight Planning System to Reduce Persistent
Contrail Formation to Reduce Greenhouse Effects
Harris Tanveer, David Gauntlett, Jhonnattan Diaz, Po-Cheng Yeh
Context
Method of Analysis
Problem & Need for ISSR Avoidance
Diaz, Gauntlett, Tanveer, Yeh
Projected Growth in Air Travel Requires Attention to Climate
Impacts
Diaz, Gauntlett, Tanveer, Yeh
Contrails Cause Net Warming Effects When Summed Across All
Tradeoff per Flight Path Between RFContrails and RFExcessCO2 is
•
Alights and All Conditions
Based on CO2’s Contribution to Global CO2 Emissions and
8.11 ! ! ! Emission Model
 RFContrails+ContrailInducedCirrus ≈ RFCO2
around
• 8.11 ! ! ! Emission
through
Global RF
Model • model will be utilized to calculate
The following mathematical
! ! emissions for a
 To reduce RF from contrails, ISSR can be– avoided
strategic
The flight
following
mathematical
model
! emissions
for a
9 Alternatives with different Avoidance Aggressiveness and
particular
path:by
– will be utilized to calculate ! 
𝐅𝐮𝐞𝐥 𝐂𝐨𝐧𝐬𝐮𝐦𝐩𝐭𝐢𝐨𝐧
= 𝜂 × Thr × 𝐶𝑓𝑐𝑟
Flight Lengths with 45 atmospheric combinations
! ! !! " #$$#%& = ! ∗ ! ,
particular flight path:
flight planning
Independent Variables
Outputs
! is the fuel consumed, c is a chemical
(C02
by stoichiometric
! ! !! " constant
#$$#%& =
! ∗produced
!,

𝐂𝐎
𝐄𝐦𝐢𝐬𝐬𝐢𝐨𝐧𝐬
=
𝑓
∗
3.175
𝟐
 Avoiding ISSR may cause
Avoidance Flight Length Atmospheric
combustion
known
amount ofcfuel.
! = !3.175!constant (C02
). produced by stoichiometric
! is theoffuel
consumed,
is a chemical
Aggression
Configurations
increase in:
 𝐑𝐞𝐥𝐚𝐭𝐢𝐯𝐞 𝐇𝐮𝐦𝐢𝐝𝐢𝐭𝐲 𝐰𝐢𝐭𝐡 𝐑𝐞𝐬𝐩𝐞𝐜𝐭 𝐭𝐨 𝐈𝐜𝐞
!
!
!
!
• 4.2 million passengers/year
increase from 2013 to 2033
• 54.85% projected increase
in passengers from 2013 to
2033
! " !! ! !
! " !! " #$
•
•
•
•
combustion of known amount of fuel. ! = !3.175!
Excess distance flown
Excess fuel consumption
RF from excess CO2 emissions
RF from contrail formation
! " !! ! !
! " !! " #$
).
used [3]:
•
•
In order to determine if persistent6.0612!
contrails
be" #.!
formed,
the following
! " .!will
" #! /(!
"! ! )
 𝑹𝑭 formula will𝒕be=
! " #= ! " #
used [3]:
𝑪𝒐𝒏𝒕𝒓𝒂𝒊𝒍𝒔
6.1162!
! ! .! " " ! /(! " #.! " ! ! )
Source: Form 41 and 298C, U.S. DOT 2005: 641 Tg/yr CO2 by Aviation Industry
" #= !
Cirrus RF ≈! 30
mW/m^2
"#
 𝑹𝑭𝑬𝒙𝒄𝒆𝒔𝒔𝑪𝑶
! .! " "100%
! /(! " #.!
" ! ! )that persistent
determine if and when contrails will form. A6.1162!
value of !over
means
contrail 𝟐
Z
Complete
Avoidance
Medium
Long
Flight Length:
•Short: < 500 nm
•Medium: 500 – 1000 nm
•Long: > 1,000 nm
!!!
!!
!"
#
!
!
=
!
!
1
! from
!
In order to estimate the contrail emission
the−exhaust,
the Schumann (2002) Ice
100
Contrail
Induced cirrus
Destination
Water
Content
todensity
! ! ! will
be !used:
where
! ! is the
of air,
! is the saturation mixing ratio with respect to ice at the ambient
clouds may increase
!" # ! ! RF=by
!! ! !
−1
Total Aviation
100
-2
41%of (0.055
where ! ! is the density
air, ! ! is theWm
saturationtomixing ratio with respect to ice at the ambient
-2)
0.078
Wm
temperature, and ! ! ! is the percentage of relative humidity with respect to ice.
Red: Travel Through ISSR
Blue: ISSR Avoidance
A
Simulation Facts:
•Output: 54,000 flight
combinations
•Simulation uses 3-D
modified A* routing
algorithm
X
52
Recommendations & Future Work
52
As ISSR Avoidance Increases, Cost Increases and Total RF
Decreases per Flight Path
Average Total RF vs. Average Cost per Flight Path
Alternatives Comparison
Histograms of % of Distance in ISSR by Avoidance Type
0.6
0.9
1.2
1.5
1.8
% DistISSR_Long, Complete
97% decrease in Average % of Distance in
ISSR
50
0
Percent
% DistISSR_Medium, No Avoidance
% DistISSR_Medium, Complete
95% decrease in Average % of Distance in
ISSR
% DistISSR_Short, No Avoidance
100
% DistISSR_Short, Complete
100
50
0
76% decrease in Average % of Distance in
ISSR
50
0.0
0.3
0.6
0.9
1.2
1.5
4.5E-11
4E-11
3.5E-11
3E-11
2.5E-11
2E-11
1.5E-11
1E-11
5E-12
0
Long: 18.5% decrease from 0% to 100% Avoidance
Medium: 18.4% decrease from 0% to 100% Avoidance
Short: 18.1% decrease from 0% to 100% Avoidance
0%
10%
20%
RF Contrails > RF ExcessCO2
40%
50%
60%
70%
80%
90%
$20%
40%
60%
ISSR Avoidance Percentage
Avg RF Excess CO2 (L)
Avg RF Contrails (L)
80%
100%
20%
30%
40%
50%
60%
ISSR Avoidance Percentage
Long
Medium
Short
No Avoidance, Short
1E-11
Short Flights
5E-12
Partial Avoidance, Short
0
Complete Avoidance, Short
$50.00
$100.00
$150.00
$200.00
% Decrease in Average
% Increase in Average Cost
Total RF (No Avoidance to
(No Avoidance to
Complete Avoidance)
Complete Avoidance)
Short: 4.14% increase from 0% to 100% Avoidance
10%
Complete Avoidance, Medium
1.5E-11
$250.00
Average Cost (Fuel Cost in $)
Medium: 1.33% increase from 0% to 100% Avoidance
0%
Medium Flights
$-
$150.00
$50.00
Partial Avoidance, Medium
2E-11
Fuel Cost vs ISSR Avoidance
$100.00
No Avoidance, Medium
2.5E-11
$200.00
RF Contrails
< RF ExcessCO2
Complete Avoidance, Long
3E-11
100%
No Avoidance, Long
Partial Avoidance, Long
3.5E-11
Long: 0.94% increase from 0% to 100% Avoidance
Fuel Cost ($)
At 99% Avoidance- Benefits of avoiding ISSR are
outweighed by RFExcessCO2 for Long Flights
30%
Long Flights
4E-11
ISSR Avoidance Percentage
Long
Medium
Short
$250.00
Radiative Forcing vs. ISSR Avoidance Percentage
9E-12
8E-12
7E-12
6E-12
5E-12
4E-12
3E-12
2E-12
1E-12
0
Total RF (CO2 + Contrails Decreases with ISSR Avoidance)
1.8
% of Distance in ISSR
4.5E-11
Average Total RF (W/m^2)
% DistISSR_Long, No Avoidance
100
0.3
Total Radiative Forcing (W/m^2)
0.0
• Fuel Burn
• CO2 emissions
• Radiative Forcing (Contrails
and CO2)
• Flight Distance
• Flight Duration
• %Distance in ISSR
Short
𝑚𝑊
𝑚2
Water Content to ! ! will be used:
Origin
As Distance Traveled in ISSR Decreases, RFContrails Decreases,
and RFExcessCO2 Increases
Radiative Forcing (W/m^2)
30
!
is obtained from the RAP
data [3].
Results
0%
Medium
! ! respect to ice.
temperature, and ! ! ! is the percentage of relative
humidity! with
!!
between incoming shortwave
radiation and outgoing longwave
radiation
0
Partial
Avoidance
formation is considered favorable. The value RHw is relative humidity with respect to water, and
ISSR
𝑚
Short
Flights
45 days of
weather from
NOAA’s RUC
Database
Short
In order to estimate the contrail emission from the exhaust, the Schumann (2002) Ice
Radiative Forcing (RF) 𝑊
energy/area 2 difference
Medium
Flights
𝑆𝑢𝑟𝑓𝑎𝑐𝑒 𝐴𝑟𝑒𝑎𝐸𝑎𝑟𝑡ℎ
is obtained
fromwhen
the RAP
data [3].
determine
if and
contrails
will form. A value of over 100% means that persistent contrail
B
Long
Flights
Medium
Long
𝑅𝐹𝐿𝑊+𝑆𝑊 𝑡,𝑠 𝑊 𝑡,𝑠 𝑑𝑠
𝐸𝑥𝑐𝑒𝑠𝑠 𝐶𝑂2
641 𝑇𝑔 𝐶𝑂2
=
formation
is considered
favorable.with
Therespect
value RHw
is relative
humidity
with allows
respect to
RHi or
relative humidity
to ice
is a measure
which
thewater,
teamand
to
Treat ISSR as “bad weather” areas to
maneuver around
𝑓𝑙𝑖𝑔ℎ𝑡𝑠
No
Avoidance
Long
RHi or relative
humidity
with respect6.0612!
to ice is a! "measure
the team to
.! " #! /(! "which
#.! " ! !allows
)
Contrails
+ Induced
Y
Short
18.102𝑇/(249.52+𝑇)
6.0612𝑒
8.12 Contrail Model
𝑅𝐻𝑖 =
22.577𝑇/(273.78+𝑇)
6.1162𝑒
In order to determine if persistent contrails will be formed, the following formula will be
8.12 Contrail Model
70%
80%
90%
100%
Long Flight
18.49%
0.94%
Medium Flight
18.35%
1.33%
Short Flight
18.07%
4.14%
Recommendation:
Pilot testing should be
conducted at 99% ISSR
Avoidance for Long, Medium,
and Short distance flights
Future Work:
• Who should pay for increased fuel and crew costs as distance increases?
• How is passenger comfort impacted from ISSR avoidance
• How can ISSR avoidance be combined with wind optimal flight paths
Systems Engineering & Operations Research, George Mason University