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2017 Aircraft LTO Data Processing for the
National Emission Inventory

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EPA-454/B-19-032
July 2018
2017 Aircraft LTO Data Processing for the National Emission Inventory
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Air Quality Assessment Division
Research Triangle Park, NC

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2.017 Aircraft LTO Data Processing for the National Emission Inventory
Purpose
To assist state, local, and tribal agencies in their submittal of aircraft-related activity data, EPA has
compiled the aircraft landing and takeoff (LTO) data from several Federal Aviation Administration's
(FAA) data sources including the 2017 T-100 dataset, which provides activity for large commercial
aircraft and represents a majority of the emissions. To ensure completeness, the FAA's 2014 Terminal
Area Forecast (TAF) data, 2014 Air Traffic Activity Data Systems (ATADS) data, and 2014 Airport Master
Record (form 5010) data are also used to capture the smaller general aviation (GA), air taxis (AT) and
military operations. These aircraft activity data are compiled and provided for review and revision by
agencies in order to accurately estimate activity data for all aircraft types. These compiled data,
including local revisions, will be used to calculate the 2017 National Emission Inventory (NEI) aviation
emissions using the FAA's new Aviation Environmental Design Tool (AEDT).
Please note that by reviewing and correcting the LTO data in this dataset you will NOT need to submit an
airport emissions file to EIS. If you send the LTO and facility revisions back to EPA now, EPA will perform
the processing tasks required, such as applying the activity data to AEDT to estimate emissions,
matching EIS facility, unit, and process IDs for the airports, as well submitting the emissions inventory to
the EIS Gateway. This will be the easiest way for agencies to submit local aviation data into EIS. Those
who choose not to participate in this data gathering process, but still want local emissions data included
in EIS, will be required to prepare their data to meet all EIS input requirements and submit it
themselves.
Background
The T-100 data is derived from commercial aviation operations, reported directly by the airlines and
specifically includes detailed information about large commercial air carriers and air taxis. Because the
T-100 aircraft data are provided for individual aircraft, specifying manufacturer and aircraft model, they
can be matched to specific aircraft in the FAA's new AEDT, which is a SQL based software tool used to
estimate emissions. Please note the previous FAA's Emission Dispersion and Modeling Systems (EDMS)
emissions will not be accepted by the EPA for current and future versions of the NEI. Because of the
details provided in T-100, it is possible to identify which aircraft are typically used for air taxi services
based on typical passenger capacity. All non-air taxi data in the T-100 data are assumed to be large
commercial aircraft.
The FAA's TAF and ATADS datasets do not provide operations data at the aircraft manufacturer and
model level of detail that the T-100 data does; instead, operations are provided for general aircraft
types (i.e., air carriers, air taxis, general aviation and military). ATADS includes actual operations at FAA
controlled facilities, while TAF includes the ATADS data and also modeled operations for other non-FAA
control facilities. Note that the TAF and ATADS data are provided as operations (separate operation

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counts for each landing and takeoff leg), such that the TAF and ATADS operations need to be divided by
2 to get LTOs.
Previously the TAF/ATADS data were adjusted because both the T-100 data and the TAF/ATADS data are
reported by the airports include commercial air carriers and air taxis, the data needs to be adjusted to
avoid issues of double counting when the two datasets are combined. However due to limited
resources, the EPA is using the 2014 TAF/ATADS data as used for 2014 NEI (after reconciliation with
T100 and without any growth adjustment from 2014 to 2017) for the 2017 NEI with the assumption the
overlap is not significant and cannot be quantified between the differing years.
The 5010 forms are used for airport infrastructure planning include a variety of information about
airport operations and characteristics. Such information is particularly important for smaller facilities
where data sources are sparse. The EPA reviewed the data reported in the 5010 submittals to estimate
LTO activity for general aviation and air taxis. Again, EPA used the 5010 as adjusted for 2014 NEI with no
growth for 2017. These carryover generic LTOs from the 2014NEI are identified as such.
Reviewing/Revising Data
EPA's compiled , Jata are available for state/local/tribal (SLT) agency review. The data are presented
as a Microsoft Access database. Please do not review/revise the Access data. The database includes two
drop-down menus: one for selecting data by state and one for selecting data by tribal code. Once the
state/tribe has been selected, users have the option of viewing the data in Access (this is Read Only and
for review ONLY) and exporting the data to a Microsoft Excel spreadsheet for further actual review and
revisions. Agencies will need to review both the LTO data as well as facility information. The LTO data
will include the Airport identification information, aircraft information, and LTO data. The facility data
will include airport identification information, address, coordinates, description, and operating status.
Please note that to export the data to Excel, the user will first need to create a folder on the C drive of
their computer called "2017 NEI LTO Review" (C:\2017 NEI LTO Review). The exported Excel file(s) will
be generated in this folder. Revisions should be made in the Excel files as described below to facilitate
EPA processing and avoid errors:
	Revising Data: Existing LTO data can be corrected by adding the new data value to the "Revised
LTO" column and marking it as a "Revision" in the "Revisions Comment" field.
	Removing Data: Please DO NOT DELETE ANY ROWS in the Excel spreadsheet. If you want to
remove LTO data, simply change the "Revised LTO" column to 0 and mark it as a "Revision" in
the "Revisions Comment" field.
	Adding Data: Rows can be added to account for new aircraft or engine type combination. Please
make sure that the airport, aircraft, and engine combination does not already exist in the
dataset before adding new rows, as adding an existing combination may cause double counting.
When adding a row, fill in all other fields when possible, including the EISFacilitySiteldentifier

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where possible. Also, leave the "PrimaryKey" and the "EPA LTO" fields blank, as these fields are
for internal record keeping.
	The EPA will assume a default taxi in time of 7 minutes and a default taxi out time of 19 minutes.
If states want to revise the taxi in or out time for specific airports please add the correct times in
revised taxi in time and revised taxi out time columns.
	Please note there are some airports in the dataset with limited information pertaining to the
airport name, county FIPs, and addresses. Please add additional information if possible.
	There may also be issues with geographic data for airports. For many of the new airports the
latitude and longitude are inconsistent with the FIP, city, state, and zipcode. Please review and
correct these issues if possible.
See Tables 1, 2, 3, and 4 for examples on how to correctly submit LTO revisions. See Tables 5, 6, and 7
for examples on how to correctly submit airport revisions. Please note that some ElS-required fields (i.e.,
EISEmissionsUnitldentifier and EISEmissionsProcessldentifier) are not included in the database. These
fields were removed to simplify the data revision process and will be added by EPA. The
EISFacilitySiteldentifier, which is unique, is included, however, to avoid errors resulting from duplication
of the more common three-digit alphanumeric airport code, FacilitySiteldentifier. (Note that the
FacilitySiteldentifier indicated may be one of many alternate ones for a given airport). Some airports in
the database currently do not have an EISFacilitySiteldentifier; EPA will add these during processing. If
your airport is not included in this database (either with or without an EISFacilitySiteldentifier) please
add the airport and be prepared to provide the airport's street address, city, state, zip, and
latitude/longitude coordinates in the airport revisions.
For additional information on whether or not LTOs should be updated/replaced or left untouched as is,
especially in regard to the generic data from ATADS/TAF and/or 5010 please refer to Appendix A for
more information and examples.
The AircraftEngineTypeCodes are available under the Reporting Code Tables link in the EIS gateway. It
should be noted that are some records that look like duplicates in the reporting code table. These are
not actually duplicates. There are additional details about the version of the aircraft engine used on the
FAA's AEDT software. This additional information relates to engine modifications that have occurred
over the time. However, as engine modification data for individual aircraft are difficult to find, it is
recommended that the lowest numeric ID in any set of "duplicates" be used if the engine modification is
not known. These additional details can be found in the Excel file called AETC_Engine_Mode.xlsx, which
is an abbreviated AircraftEngineTypeCode Reporting Code table with engine modification data added.
Submitting Data t
States must submit their changes by September 14, 2018 to this email address managed by EPA's
contractor Eastern Research Group (ERG). If no changes are required, you may indicate that you accept
EPA's data via an EIS support request (as you would for any category of data for which you accept EPA
estimates), or by sending an email indicating acceptance to the above address. Note this email account

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has a 10 MB limit. If a state submittal is larger than 10 MB, a message can be left at this e-mail address
requesting data transfer using a secure FTP site. A representative from ERG will respond to this request
with instructions how to access the FTP site.
The EPA will review the state-submitted data to ensure that it is appropriate and reasonable. Once the
LTO data have been finalized, then the aircraft specific LTO data will be run using the latest version of
AEDT to estimate criteria and HAP emissions for aircraft engine exhaust, auxiliary power units, and
ground support equipment. The remaining aircraft type data will be applied to generic emission factors.
If you need assistance, contact Laurel Driver at 919.541.2859.
Note EPA strongly encourages agencies to review and, if necessary, submit their LTO data to the EPA
via this review process. In doing so, then states need not submit EIS staging tables for the 2017 NEI
and they are ensured that the latest FAA model will be used consistently to estimate their emissions.

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Table 1. Exported LTO Data from Access Database for Review (no changes)
Primary
Key
StateAnd
County
FlPSCode
Tribal
Code
Airport
State
FacilitySite
Identifier
EISFacility
Site
Identifier
Sou rce
Classification
Code
Process
Description
Aircraft
Engine
TypeCode
EPA_
LTO
Revised_
LTO
RevisedTGO
Revised_
Taxi_ln_
(default_7_min)
Revised_
Taxi_Out_
(default_19_min)
Revision
Comment
1
37001

Example
Airport
NC
AAA
10000000
2275050011
Aircraft/
General Aviation /Pisto
999903
100





2
37001

Example
Airport
NC
AAA
10000000
2275020000
Aircraft/Commercial
1412
150





*NOTE: Do not change the Primary Key, these are for internal tracking purposes.
Table 2. Example of a LTO revision to an existing record
Primary
Key
StateAnd
County
FlPSCode
Tribal
Code
Airport
State
FacilitySite
Identifier
EISFacility
Site
Identifier
Source
Classification
Code
Process
Description
Aircraft
Engine
TypeCode
EPA_
LTO
LTO
RevisedTGO
Revised_
Taxi_ln_
(default_7_min)
Revised_
Taxi_Out_
(default_19_min)
Revision
Comment
1
37001

Example
Airport
NC
AAA
10000000
2275050011
aft /General Aviation /
999903
100
82


12
Revision
*NOTE: Do not change the Primary Key, these are for interna tracking purposes.
Table 3. Example of a LTO deletion of an existing record
Primary
Key
StateAnd
County
FlPSCode
Tribal
Code
Airport
State
FacilitySite
Identifier
EISFacility
Site
Identifier
Sou rce
Classification
Code
Process
Description
Aircraft
Engine
TypeCode
EPA_
LTO
Revised_
LTO
RevisedTGO
Revised_
Taxi_ln_
(default 7 min)
Revised_
Taxi_Out_
(default 19 min)
Revision
Comment
2
37001

Example
Airport
NC
AAA
10000000
2275020000
Aircraft/Commerc
1412
150
0



Revision
*NOTE: Do not change t
lie Primary Key, these are for internal tracking purposes.

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Table 4. Example of a LTO additions to the existing dataset
Primary
Key
StateAnd
County
FlPSCode
Tribal
Code
Airport
Stat
e
FacilitySite
Identifier
EISFacility
Site
Identifier
Source
Classification
Code
Process
Description
Aircraft
Engine
TypeCode
EPA_
LTO
Revised_
LTO
Revised_T
60
Revised_
TaxiJ n_
(default_7_min)
Revised_
Taxi_Out_
(default_19_min)
Revision
Comment

37001

Example
Airport
NC
AAA
10000000
2275050011
Aircraft /General
Aviation /Piston
1415

25


12
Addition

37001

Example
Airport
NC
AAB
10000001
2275020000
Aircraft/Commer
cial
1418

30

5

Addition
*NOTE: Primary Keys are null for additions.
Table 5. Example of Airport Data to review
AirportKey
StateAnd
County
FlPSCode
Tribal
Code
Airport
City
State
ZIP
Latitude
Longitude
Facility
Siteldentifier
EISFacility
Siteldentifier
OpStatus
RevisionNotes
293
37001

Example Airport
City
NC
27703
54.14472
-165.60416
AAA

Open

*NOTE: Do not change the Airport Key, these are for internal tracking purposes.
Table 6. Example of Airport Data revised
AirportKey
StateAnd
County
FlPSCode
Tribal
Code
Airport
City
State
ZIP
Latitude
Longitude
Facility
Siteldentifier
EISFacility
Siteldentifier
OpStatus
RevisionNotes
293
37001

Example Airport
Town
NC
27703
99.999
9999.999
AAA

Open
Revised City, Lat,
and Long
*NOTE: Do not change the Airport Key, these are for internal tracking purposes.
Table 7. Example of Airport Data additional
AirportKey
StateAnd
County
FlPSCode
Tribal
Code
Airport
City
State
ZIP
Latitude
Longitude
Facility
Siteldentifier
EISFacility
Siteldentifier
OpStatus
RevisionNotes

37001

New Airport
Place
NC
27703
55.5555
777.7777
ZZZ

New, since
2014 Inventory
New Airport
*NOTE: AirportKeys are null for additions.

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Appendix A
Because of the potential overlap between data sources, some double counting of LTOs can occur between the specific data (T-100) and the generic
(ATADS/TAF and 5010). The T-100 data is preferred. It should also be noted that FAA is continually updating their ATADS/TAF data as more data become
available therefore it is not unusual to see changes between ATADS/TAF data downloads.
When reviewing the generic data, if large differences seem to appear between what is in the NEI LTO database for review and the data downloaded, you
may want to consider updating the data, but note it is important to first subtract the corresponding specific data (T100) at the SCC level first to ensure
that the LTO comparison is compatible. It is up to the states discretion, but if the differences between your data and NEI's data are close, it's is EPA's
recommendation that LTO data no need to be revised. Examples of when to update 2017 generic LTOs are provided below.
FacilitySite
Identifier
Source
ClassificationCode
ProcessDescription
2017
ATADS/TAF
2017 T100
2017 Generic
For Review
Percent
Change
Suggested Action
DAB
2275060011
Air Taxi, Piston
12,239

943
1198%
Update 2017 generic LTO
DAB
2275060012
Air Taxi, Turbine
43,905
44
3,382
1198%
Update 2017 generic LTO
DAB
2275050011
General Aviation, Piston
68,038

100,104
-32%
Update 2017 generic LTO
DAB
2275050012
General Aviation, Turbine
26,328
6
38,737
-32%
Update 2017 generic LTO
DAB
2275001000
Military Aircraft, Total
562

554
1%
Do not update/add 2017 generic LTO, close
DAB
2275020000
Commercial Aircraft, Total: All Types
3,235
3,199

1%
Do not update/add 2017 generic LTO, T100 present
DAB
Total
154,307
3,249
143,719


MDW
2275060011
Air Taxi, Piston
3,064

2,803
9%
Do not update/add 2017 generic LTO, close
MDW
2275060012
Air Taxi, Turbine
10,991
581
7,889
39%
Update 2017 generic LTO
MDW
2275050011
General Aviation, Piston
12,879

13,002
-1%
Do not update/add 2017 generic LTO, close
MDW
2275050012
General Aviation, Turbine
4,983
693
4,992
0%
Do not update/add 2017 generic LTO, close
MDW
2275001000
Military Aircraft, Total
553
1
914
-40%
Update 2017 generic LTO
MDW
2275020000
Commercial Aircraft, Total: All Types
93,201
92,625

1%
Do not update/add 2017 generic LTO, T100 present
MDW
Total
125,671
93,900
29,600


ORD
2275060011
Air Taxi, Piston
24,891

35,589
-30%
Update 2017 generic LTO
ORD
2275060012
Air Taxi, Turbine
89,287
106,798
125,586
-16%
Update to 0 LTOs, T100 present and higher
ORD
2275050011
General Aviation, Piston
2,158

2,514
-14%
Do not update/add 2017 generic LTO
ORD
2275050012
General Aviation, Turbine
835
3,083
972
-73%
Do not update/add 2017 generic LTO, T100 present
ORD
2275001000
Military Aircraft, Total
52

98
-47%
Do not update/add 2017 generic LTO
ORD
2275020000
Commercial Aircraft, Total: All Types
316,302
314,987

0%
Do not update/add 2017 generic LTO, T100 present
ORD
Total
433,525
424,868
164,759



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United States	Office of Air Quality Planning and Standards	Publication No. EPA-454/B-19-032
Environmental Protection	Air Quality Assessment Division	July 2018
Agency	Research Triangle Park, NC

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