GA Survey Methodology

Appendix A: Methodology for the 2022 General Aviation
and Part 135 Activity Survey

APPENDIX A
METHODOLOGY FOR THE 2022 GENERAL AVIATION
AND PART 135 ACTIVITY SURVEY
Purpose of Survey
The General Aviation and Part 135 Activity Survey (GA Survey) provides the Federal Aviation
Administration (FAA) information on general aviation and on-demand Part 135 aircraft activity.
The survey enables the FAA to monitor the general aviation fleet to anticipate and meet demand
for National Airspace System (NAS) facilities and services, assess the impact of regulatory
changes on the fleet, and implement measures to assure the safe operation of all aircraft in the
NAS. The data are also used by other government agencies, the general aviation industry, trade
associations, and private businesses to identify safety problems and to form the basis for
research and analysis of general aviation issues.
Background and History
Before the first implementation of the annual GA Survey in 1978, the FAA used the Aircraft
Registration Eligibility, Identification, and Activity Report (AC Form 8050-73) to collect data on
general aviation activity. The form was sent annually to all owners of civil aircraft in the United
States and served two purposes: a) Part 1 was the mandatory aircraft registration revalidation
form; and b) Part 2 was voluntary and applied to general aviation aircraft only, asking questions
on the owner-discretionary characteristics of the aircraft such as flight hours, avionics
equipment, base location, and use. The FAA used this information to estimate aircraft activity.
In 1978, the FAA replaced AC Form 8050-73 with a new system. Part 1 was replaced by a
triennial registration program. In January 1978, the FAA implemented a new procedure, known
as triennial revalidation, for maintaining its master file. Instead of requiring all aircraft owners to
revalidate and update their aircraft registration annually, the FAA only required revalidation for
those aircraft owners who had not contacted the FAA Registry for three years. In 2010, the FAA
eliminated the voluntary Triennial Aircraft Registration Report Program and established rules
that require renewal of an aircraft registration every three years and place time limits on interim
statuses.1
The General Aviation Activity Survey replaced Part 2 of AC Form 8050-73. The survey was
conducted annually, based on a statistically selected sample of aircraft, and requested the same
type of information as Part 2 of AC Form 8050-73. The first survey took place in 1978 and
collected data on the 1977 general aviation fleet. The 2022 statistics in this report are based on
the 45th GA Survey, which was implemented in 2023.2

Federal Register Vol 75, No. 138, Tuesday, July 20, 2010, Rules and Regulations, “Re-Registration and
Renewal of Aircraft Registration.”
2 The name of the survey has changed periodically since 1977. In 1993, the survey was entitled “General
Aviation and Air Taxi Activity Survey” to reflect the inclusion of air taxi (on-demand Part 135) aircraft. In
1999, the survey name changed to General Aviation and Air Taxi Activity and Avionics Survey because
questions about avionics were included every year rather than every other year. Since 2006, the survey
has been conducted as the General Aviation and Part 135 Activity Survey.
1

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Appendix A: Methodology for the 2022 General Aviation
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The GA Survey has undergone periodic revisions to content, implementation, and definition of
the GA population to remain current with regulations, activity patterns, and aviation technology.
Chapter 1 of this report (“Historical General Aviation and Air Taxi Measures”) presents statistical
estimates of fleet size and activity for the current and ten previous years.3 Tables A.1 through
A.3 summarize changes in survey content and design, data collection methods, sample and
population definitions that may affect the comparability of statistical estimates across surveys.
Table A.1: Changes in Form or Content of Survey Questionnaire by Survey Year
Year

Change in form or content of the survey questionnaire

1993

Added sightseeing and external load to use categories

1996

Added public use (i.e., flights for the purpose of fulfilling a government function) to use
categories

1999

Re-design the survey form to reduce item non-response, add new content, and be compatible
with optical scanning
Added air medical services to use categories
Discontinued the “other” use category as used in previous years
Began collecting avionics data every year rather than every other year

2000

“Public use” asked as a separate question

2002

Use categories refined to be mutually exclusive and exhaustive and match definitions used by
National Transportation Safety Board for accident reporting

2004

Air medical services was divided into two types to capture air medical flights under Part 135
and air medical flights not covered by Part 135
A more clearly defined “other” use category was reintroduced

2005

Fractional ownership question was changed from yes/no to a percentage of hours flown
Reduced the number of fuel-type response categories by removing obsolete options
Average fuel consumption (in gallons per hour) was added
Revised questions about avionics equipment by adding and rearranging items

2007

Location of aircraft revised to ask the state or territory in which the aircraft was “primarily
flown” during the survey year rather than where it was "based” as of December 31st of the
survey year
Percentage of hours flown in Alaska was added
Questions on percentage of hours flown under different flight plans, flight conditions, and
day/night were revised into a single tabular format
Number of types of landing gear systems was expanded
Ice protection equipment was revised and prohibition from flight in icing conditions was added
Questions about avionics equipment were revised

3 Excluding

estimates for the 2011 survey year, which are not available. For 2011 GA data, use the FAA
Aerospace Forecast estimates
(http://www.faa.gov/data_research/aviation/aerospace_forecasts/media/Tables_28-31.xlsx).

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Appendix A: Methodology for the 2022 General Aviation
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Year

Change in form or content of the survey questionnaire

2009

Two questions about avionics equipment were revised:
“Air Bag/Ballistic Parachute” was asked as two items—“Air Bag” and “Ballistic
Parachute”
“ADS-B (Mode S)” was separated into two questions—“ADS-B (Mode S) Transmit
Only (Out)” and “ADS-B (Mode S) Transmit and Receive (In)”

2010

Removed the skip instruction in the mail survey based on responses to Part 121/129
operations
Added “Specify” option if reason not flown was “Other”

2013

Added “Specify” option if fuel type was “Other”
Added response categories for reason not flown (“Under maintenance or repair,” “Parted
out/salvaged,” and “In storage”)
The text “Corporate/Executive Transportation” was removed from the description of this use
category and replaced with “Business Transportation – (with a paid flight crew).” The
definition of this use is unchanged.

2014

Added response category for kind/grade of fuel primarily used (”Propane/LP Gas”)

2016

The following questions on the 2016 full survey form underwent additions, deletions, and text
changes:
• Reason not flown
• Percentage of total hours flown under fractional ownership
• Percentage of total hours flown under filed flight plans
• Fuel type
• Avionics.
Other questions and response categories were re-ordered. Data end-users should consult the
survey documents in Appendix B of the current and previous year’s survey report.

2019

Eliminated non-mutually exclusive transponder selection options in “Installed
Transponder/Surveillance Equipment” section of avionics questions

2021

Added “Aviation Fuel: Low Octane Unleaded (UL91, UL94)” as a response category to
kind/grade of fuel primarily used by the aircraft

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Appendix A: Methodology for the 2022 General Aviation
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Table A.2: Changes in Data Collection Methodology, by Survey Year
Year

Change in data collection methodology

1999

Non-respondent telephone survey conducted to adjust active aircraft and hours flown
estimates4

2000

Discontinued non-respondent telephone survey Added Internet response option

2003

Added a reminder/thank-you postcard between the first and second mailings

2004

Introduced “large fleet” summary form for owners/operators of multiple aircraft Initiated
telephone follow-up effort to contact owners/operators of multiple aircraft who had not
responded.

2010

Introduced end-of-field-period follow-up postcard to owners/operators of single aircraft that
participated the previous survey year but had not yet completed the current year’s survey

2014

Introduced use of email to invite sampled aircraft owners/operators to complete the survey

Table A.3: Changes in Sample Design or Definition of Survey Population, by Survey Year
Year

Change in sample design or survey population

1993

Number of aircraft types classified by the sample was expanded from 13 to 19

1999

Sample design revised to stratify by aircraft type and FAA region

2003

Aircraft with known incorrect addresses and identified as “Postmaster Return” status on the
Registry were retained in the definition of the survey population and eligible for sample
selection

2004

Aircraft listed on the Registry as “registration pending” or “sold” (if sold status less than five
years ago) were retained in the definition of the survey population and eligible for sample
selection. Sample design revised to stratify by aircraft type, FAA region, and whether the
aircraft is certified to fly Part 135. Introduced 100 percent samples of turbine aircraft,
rotorcraft, on-demand Part 135, and Alaska-based aircraft

2005

Introduced light-sport aircraft as an aircraft type sampled at 100 percent. Light-sport included
aircraft with special or experimental airworthiness as well as aircraft for which airworthiness
was not yet final.

2006

Sample design simplified to fewer aircraft types and included 100 percent sample of aircraft
manufactured in the past five years

2008

100 percent sample of light-sport aircraft was limited to special light-sport aircraft.
Experimental light-sport and light-sport without completed airworthiness sampled at a rate
less than 1.0.

2010

Aircraft excluded from the survey population if “sale reported” or “registration pending” more
than 12 months. These aircraft no longer eligible for sample selection due to implementation
of the re-registration rule.

2012

5

Aircraft excluded from the survey population if registration was expired. These aircraft no
longer eligible for sample selection because they do not have valid registrations due to
implementation of the re-registration rule.
Unmanned aerial vehicles are excluded from the survey population.

4

Telephone surveys of non-respondents also were conducted in 1977, 1978, 1979, 1997, and 1998.
Please refer to the 1999 GA Survey report for a full discussion of the telephone survey of nonrespondents.
5 Before 1999, the sample was stratified by aircraft type and state or territory.

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Appendix A: Methodology for the 2022 General Aviation
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Survey Population and Survey Sample
The survey population for the 2022 General Aviation and Part 135 Activity Survey includes all
civil aircraft registered with the FAA based in the US or US territories that were in existence,
potentially active between January 1 and December 31, 2022, and had a valid registration. This
includes aircraft operating under:
•

Part 91: General operating and flight rules

•

Part 125: Certification and operations: Airplanes having a seating capacity of 20 or
more passengers or a maximum payload capacity of 6,000 pounds or more (but not
for hire)

•

Part 133: Rotorcraft external load operations

•

Part 135: On-demand (air taxi) operations

•

Part 137: Agricultural aircraft operations.

Aircraft operating under Part 121 as defined in Part 119 are excluded from the survey
population. Foreign air carriers, which operate under Part 129, are also not part of the survey
population. Civil aircraft known as not being potentially active during the survey year are
excluded from the population (e.g., aircraft on static display, destroyed before January 1, 2022).
The Aircraft Registration Master File, maintained by the FAA’s Mike Monroney Aeronautical
Center in Oklahoma City, Oklahoma, serves as the sample frame or list of cases from which a
sample of civil aircraft is selected. The Registration Master File (“Registry”) is the official record
of registered civil aircraft in the United States. To define the 2022 survey population, we used
the Registry’s list of aircraft posted on January 3, 2023.6
The Registry, like many sample frames, is an imperfect representation of the survey population.
While it may exclude a small number of aircraft that operate under the FAA regulations
governing the operation of general aviation and on-demand Part 135 aircraft, it also includes
aircraft that are not part of the survey population. Before sample selection, the following
ineligible aircraft are removed:
•

Aircraft that operate under Part 121

•

Aircraft destroyed or moved to static display before January 1, 2022

•

Aircraft based in Europe or registered to a foreign company that has not returned
flight hour reports

•

Aircraft that are unmanned aerial vehicles

6 The

Civil Aviation Registry updates the Master file approximately weekly but there can be a backlog of
records to process. Record processing was farther behind schedule in 2022 than previous years. The
Registry Master file available on January 3, 2023, reflected records processed through July 7, 2022.

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Appendix A: Methodology for the 2022 General Aviation
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•

Aircraft whose registration has been canceled or revoked, or expired before January
1, 2022

•

Aircraft listed as “sale reported” or “registration pending” for more than 12 months
(before January 1, 2022)7

The Registry Master file used to define the 2022 survey population included 287,696 aircraft.
After excluding the aircraft described above, 268,815 records remain (93 percent of the Registry
Master file).
The 2022 GA Survey Sample
The 2022 survey sample is stratified by aircraft type, FAA region in which the aircraft is
registered, whether the aircraft operates under a Part 135 certificate, and whether the aircraft
was manufactured in the past five years. Aircraft operated under a Part 135 certificate were
identified using the FAA’s Operations Safety System (OPSS) database merged with the
Registry by N-number.
Aircraft are classified into FAA regions by the state or US territory of registration. Table A.4
summarizes how states and territories are mapped to region.8

7

The registration rule allows aircraft to be listed as sale reported for registration pending for a maximum
of six months. To define the survey population, we allow aircraft to hold this status for 12 months
because we cannot consistently differentiate among aircraft that did or did not hold valid statuses for the
other six months of the year. The number of aircraft mistakenly included in the survey population should
be small. The error of including ineligible aircraft has a smaller impact on statistical estimates of activity
than erroneously excluding eligible and potentially active aircraft.
8 The FAA defines the regions at www.faa.gov/about/office_org/headquarters_offices/arc/ro_center.
Statistical estimates reported by region in which an aircraft is primarily flown follow the same mapping
based on the state in which the aircraft is primarily operated.

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Appendix A: Methodology for the 2022 General Aviation
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Table A.4: Regions and States/Territories Constituting Region
Region

States/Territories

Alaska

Alaska

Central

Iowa, Kansas, Missouri, Nebraska

Eastern

Delaware, Maryland, New Jersey, New York, Pennsylvania, Virginia, Washington,
DC, West Virginia

Great Lakes

Illinois, Indiana, Michigan, Minnesota, North Dakota, Ohio, South Dakota,
Wisconsin

New England

Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont

Northwest Mountain

Colorado, Idaho, Montana, Oregon, Utah, Washington, Wyoming

Southern

Alabama, Florida, Georgia, Kentucky, Mississippi, Navassa Island, North
Carolina, Puerto Rico, South Carolina, Tennessee, US Virgin Islands

Southwestern

Arkansas, Louisiana, New Mexico, Oklahoma, Texas

Western-Pacific

American Samoa, Arizona, Baker, Howland, and Jarvis Islands, California, Guam,
Hawaii, Johnston Atoll, Kingman Reef, Midway Islands, Nevada, Palmyra Atoll,
Wake Island

We define 15 aircraft types for the sample design. The classification distinguishes among fixed
wing aircraft, rotorcraft, experimental aircraft, light-sport, and other aircraft. Within categories of
fixed wing and rotorcraft, we differentiate by type and number of engines (e.g., piston, turbine,
single- and two-engines). Experimental aircraft are subdivided by amateur-built status and
airworthiness certification, and we classify “other” aircraft as gliders or lighter-than-air. Light
sport is subdivided into special and experimental based on airworthiness certification. Lightsport aircraft without final airworthiness certificates are included with experimental light-sport.
Aircraft Sampled at 100 Percent
The 2022 survey sample includes several types of aircraft sampled at a rate of 1.0. Because of
the FAA’s interest in understanding their operations, all such aircraft listed in the Registry are
included in the survey sample to ensure enough responses to support analysis and provide
more precise estimates of fleet size and aircraft activity. These aircraft include:
•

100 percent sample of turbine aircraft (turboprops and turbojets)

•

100 percent sample of rotorcraft

•

100 percent sample of special light-sport aircraft

•

100 percent sample of aircraft operating on-demand Part 135

•

100 percent sample of aircraft registered in Alaska

•

100 percent sample of aircraft manufactured within the past five years (since 2017
inclusive).

Aircraft sampled at 100 percent account for 59,866 observations in the survey sample.
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Appendix A: Methodology for the 2022 General Aviation
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Aircraft Sampled at Less than 100 Percent
Aircraft not part of a 100 percent sample are selected based on sampling fractions defined for
each cell in the sample design matrix. Flight hours is the primary measure needed by the FAA.
Sample fractions for each sample strata are defined to optimize sample size to obtain the
desired level of precision for an estimate of flight activity. Data from the previous survey year on
average hours flown, variability in hours flown by region and aircraft type, and response rates
are used to set precision levels and target sample sizes for each stratum. Aircraft are randomly
selected from each cell in the matrix, subject to the desired sample size. Strata where the
desired sample size exceeds the population are examined, and the sample size is adjusted to
include all observations.9 The survey sample includes 25,147 aircraft selected at a rate of less
than 1.0.
The 2022 GA Survey sample included 85,013. Table A.5 summarizes the population counts10
and sample sizes by aircraft type.

9

An additional nine strata were sampled at 100 percent to meet precision requirements (3,285 aircraft).
Population counts in Table A.5 reflect the starting population, as defined by information available on the
Registry. Final population estimates in Chapters 1–7 of this report adjusts for ineligible aircraft identified
during data collection.
10

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Appendix A: Methodology for the 2022 General Aviation
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Table A.5: Population and Survey Sample Counts by Aircraft Type

Population1

Sample Size

Sample as
Percent of
Population

175,868

30,751

17.5

1 engine, 1–3 seats

48,752

6,770

13.9

1 engine, 4+ seats

112,111

15,979

14.3

2 engines, 1–6 seats

10,684

5,579

52.2

2 engines, 7+ seats

4,321

2,423

56.1

Fixed Wing - Turboprop

11,505

11,505

100.0

1 engine

6,200

6,200

100.0

2 engines, 1–12 seats

3,651

3,651

100.0

2 engines, 13+ seats

1,654

1,654

100.0

Fixed Wing - Turbojet

16,878

16,878

100.0

Rotorcraft

12,111

12,111

100.0

Piston

3,968

3,968

100.0

Turbine (1 engine)

6,000

6,000

100.0

Turbine (multi-engine)

2,143

2,143

100.0

6,931

2,158

31.1

Glider

2,621

1,080

41.2

Lighter-than-air

4,310

1,078

25.0

Experimental

43,317

8,405

19.4

Amateur

33,277

4,622

13.9

Exhibition

3,057

1,382

45.2

Experimental light-sport2

5,876

1,357

23.1

Other experimental

1,107

1,044

94.3

3,205

3,205

100.0

269,815

85,031

31.5

Aircraft Type
Fixed Wing - Piston

Other Aircraft

Special light-sport
Total
1 Starting

population as defined by information available on the Registry. Final population estimates in
Chapters 1–7 of this report adjusts for ineligible aircraft identified during data collection.
2 Includes light-sport aircraft with experimental airworthiness and light-sport aircraft for which airworthiness
certification is not final.

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Appendix A: Methodology for the 2022 General Aviation
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Weighting the Survey Data
Data from completed surveys are weighted to reflect population characteristics. The weights
reflect the proportion of aircraft sampled from the population in each sample strata and
differential response and adjustment for aircraft that are not part of the survey population.
Initially, each aircraft for which we receive a completed survey is given a weight that reflects
sampling fraction and differential response. That is:
WEIGHT = (Population Nijkl/Sample Nijkl) * (Sample Nijkl/N Respondentsijkl)
where i, j, k, and l represent the four sample strata of aircraft type, FAA region, Part 135 status,
and whether an aircraft was manufactured in the past five years.
The weight is subsequently adjusted to reflect information about non-general aviation aircraft.
Survey responses that indicate an aircraft is not part of the survey population—e.g., destroyed
before January 1, 2022; displayed in a museum; or operated primarily under Part 121 or 129—
are used to remove aircraft from the sample and the population. The procedure assumes that
ineligible aircraft occur similarly among survey respondents and non-respondents. To the extent
that ineligible aircraft are less likely to receive and complete a survey, this approach will
underestimate the adjustment for aircraft not part of the general aviation population.
Errors in Survey Data
Errors associated with survey data include sampling and non-sampling errors. Sampling errors
occur because the estimates are based on a sample of aircraft rather than the entire population,
and we can expect, by chance alone, that some aircraft selected into the sample differ from
aircraft that were not selected.
Non-sampling errors include a) errors that arise from difficulties in the execution of the sample
(e.g., failing to obtain completed interviews with all sample units), and b) errors caused by other
factors, such as misinterpretation of questions, inability or unwillingness to provide accurate
answers or mistakes in recording or coding data.
Sampling Error
The true sampling error is never known, but in a designed survey we can estimate the potential
magnitude of error due to sampling. This estimate is the standard error. The standard error
measures the variation that would occur among the estimates from all possible samples of the
same design from the same population.
This publication reports a standard error for each estimate based on survey sample data. An
estimate and its standard error can be used to construct an interval estimate (“confidence
interval”) with a prescribed level of confidence that the interval contains the true population
figure. In general, as standard errors decrease in size, we say the estimate has greater
precision (the confidence interval is narrower), while as standard errors increase in size, the
estimate is less precise (the confidence interval is wider). Table A.6 shows selected interval
widths and their corresponding confidence.

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Appendix A: Methodology for the 2022 General Aviation
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Table A.6: Confidence Interval Estimates
Approximate
confidence
that interval includes
true population value

Width of interval
1 Standard error

68%

2 Standard error

95%

3 Standard error

99%

This report presents a “percent standard error” for each estimate, which is the standard error
relative to the mean. The percent standard error is the ratio of the standard error to its estimate
multiplied by 100. For example, if the estimate is 4,376 and the standard error is 30.632, then
the percent standard error is (30.632/4,376) x 100 = 0.7. Reporting percent standard errors
makes it possible to compare the precision of estimates across categories.
Estimates and percent standard errors reported in Table 2.1 in Chapter 2 ("Population Size,
Active Aircraft, Total Flight Hours, and Average Flight Hours by Aircraft Type") provide an
example of how to compute and interpret confidence intervals. To obtain a 95 percent
confidence interval for the estimated number of total hours flown for twin-engine fixed wing
piston aircraft with 1–6 seats in 2022, where the total hours flown is estimated to be 1,084,742
and the percent standard error of the estimate is 4.5, the following computation applies:
Lower confidence limit: 1,084,742 – 1.96(4.5/100)(1,084,742) = 989,068
Upper confidence limit: 1,084,742 + 1.96(4.5/100)(1,084,742) = 1,180,416
In other words, if we drew repeated samples of the same design, 95 percent of the estimates of
the total hours flown by twin-engine fixed wing piston aircraft with 1–6 seats would fall between
989,068 and 1,180,416.
Non-sampling Error
Sampling error is estimable and can be reduced through survey design (e.g., by increasing
sample size), but it is difficult, if not impossible, to quantify the amount of non-sampling error.
Although extensive efforts are undertaken to minimize non-sampling error, the success of these
measures cannot be quantified.
Steps taken to reduce non-sampling error include strategies to reduce non-response and efforts
to minimize measurement and coding errors. The 2022 GA Survey incorporated the following
steps to maximize cooperation among sample members:
•

Three methods for completing the survey (web, paper-pencil mail form, telephone
follow-up to fleets) and three methods of inviting survey participation (mail, email,
and telephone).

•

Three mailings of the paper survey, reminder letters and postcards, and end-of-fieldperiod follow-up postcard and email.

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Appendix A: Methodology for the 2022 General Aviation
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•

Cover letters accompanying each survey mailing explained the purpose of the survey
and the endorsement (organizational logos) of several aviation associations.

•

Cover letters assured owners of the confidentiality of their responses and informed
them: “Names of individuals are never associated with responses. There is an
identification number on your survey only so [survey contractor] knows who should
receive the letter.”

•

Use of additional sources to obtain updated contact information and help ensure the
mail survey reaches the sample member.

•

Use of a toll-free telephone number and email address to respond to questions.

•

Collaboration with aviation organizations and industry groups to raise awareness of
the survey and encourage cooperation.

•

Telephone follow-up to owners or operators of multiple aircraft who had not yet
responded.

The survey efforts minimize measurement error by increasing the likelihood that respondents
share a common understanding of survey questions and reducing errors in data coding. These
efforts include:
•

Collaboration with the FAA, other federal agencies, and aviation groups to refine
question wording and definitions to questions. The questionnaire is reviewed
regularly to identify ambiguities or revisions necessary to remain consistent with
aviation regulations and definitions.

•

Periodic re-design of the survey questionnaire and pre-testing significant revisions
with a sample of aircraft owners or operators.

•

Comprehensive editing and verification procedures to ensure the accuracy of data
transcription to machine-readable form.

•

Manual review and verification of a subset of single-aircraft mail surveys throughout
the field period.

•

Programmed logic checks for web surveys to identify illogical, unusual, or
inconsistent data.

•

Analysis of preliminary data to identify unusual or illogical values and place follow-up
inquiries with participants to verify or correct responses.

We try to reduce measurement error, but it is impossible to eliminate all measurement error.
Survey participants may misunderstand questions or misreport flight activity in ways that cannot
be prevented through survey design. Where survey reports appear nonsensical or contradict
FAA regulations, we verify the accuracy of data processing. Instances in which illogical reports
occur may be suppressed and are indicated in table notes. No additional steps are taken to
cleanse the data of apparently illogical reports or assign them to other categories. To do so
would introduce additional and systematic error that would be misleading and would affect other
uses of the data.
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Appendix A: Methodology for the 2022 General Aviation
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Imputation of Missing Data
Imputation of missing data is important for stabilizing the estimates of aircraft activity and
equipment. Values are imputed for variables if the survey response is incomplete, the survey
form did not include the question, or the Registry data field is blank. Table A.7 lists the variables
for which values are imputed, describes the procedure, and shows imputation rates among
active aircraft that received the full survey form (first column of numbers) and rates including
active aircraft that completed the short form (last column).11 Asterisks note the questions not
asked on the short form.
Table A.7: Variables with Imputed Values, Imputation Procedure, and Percentage Imputed
Among Active Aircraft

11
12

Percent
Imputed
(full
survey
form only)

Percent
Imputed (incl.
short form)

0.9

2.4

Variable

Imputation Procedure

Hours by use (e.g.,
personal, business
transport)

Mean values by aircraft type

Fractional ownership
hours12

Nearest neighbor by aircraft type
by make model series

25.1

23.5

Hours rented/leased *

Nearest neighbor by aircraft type
by make model series

5.1

42.2

Public use hours

Nearest neighbor by aircraft type
by make model series

5.1

14.5

Hours by flight
plans/flight conditions *

Mean values by aircraft type

3.3

41.1

Airframe hours *

Nearest neighbor by aircraft type
by hours flown

6.4

43.0

Number of landings

Nearest neighbor by aircraft type
by make model series by age

2.7

13.4

Landing gear *

Nearest neighbor by aircraft type
by make model series

3.1

41.0

Fuel type *

Nearest neighbor by aircraft type
by make model series

3.2

40.9

Fuel burn rate

Nearest neighbor by aircraft type
by make model series

0.7

1.9

Avionics equipment *

Nearest neighbor by aircraft type
by make model series by age

3.8 to
16.2

23.7 to
34.2

State primarily flown

Assign state of registration from
Registry

1.4

19.4

The “full” and “short” forms of the survey are described below in the section “Data Collection Methods.”
Fractional ownership is not asked on the full survey form.

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Appendix A: Methodology for the 2022 General Aviation
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Variable

Imputation Procedure

Year of manufacture
(Registry data field)

Nearest neighbor by aircraft type
by make model series

Percent
Imputed
(full
survey
form only)

Percent
Imputed (incl.
short form)

0.6

1.8

Percentages are based on unweighted survey responses among active aircraft (total 29,020).13
* Question not asked on the abbreviated survey form administered to owners/operators of multiple aircraft.

For aircraft that completed the full survey form, rates of imputations for most variables are 1 to
3.2 percent. Item non-response is lowest for year of manufacture (0.6 percent), fuel burn rate
(0.7 percent), and hours flown by use (0.9 percent). Imputation rates are slightly higher for
public use hours (5.1 percent), hours rented or leased (5.1 percent), and lifetime airframe hours
(6.4 percent).
Imputation rates for avionics equipment are reported as a range because the rates vary by item.
The full survey form collects data on 58 types of avionics equipment, and the imputation rates
range from 3.8 percent to 16.2 percent. Most items have low imputation rates: Imputation rates
are at or below 4 percent for 13 of the 58 items; 40 of the items have imputation rates of 7
percent or less. Eleven items have imputation rates greater than 10 percent. Imputation rates
are higher when the short form data are included, as shown in the last column of Table A.7. The
abbreviated survey form does not include questions on avionics.
Survey Content
The 2022 GA Survey questionnaire requests the aircraft owner or operator to provide
information on flight activity, flight conditions, where the aircraft was flown, and aircraft
characteristics. Variables derived from the survey responses include:

13

•

Number of total hours flown in 2022, hours flown by use, and lifetime airframe hours

•

The state in which the aircraft was primarily flown

•

Hours flown by filed flight plan, including flight under Visual Flight Rules (VFR),
Instrument Flight Rules (IFR), and without flight plans

•

Hours flown as part of a fractional ownership program (short form only), rented or
leased, or used to fulfill a government function

•

Type of landing gear and number of landings in 2022

•

Fuel type and average fuel burn rate

•

Avionics equipment installed in the aircraft.

Prior to the 2015 survey, the imputation rates were calculated based on all survey responses (active
and inactive aircraft). The rates shown here will not be comparable to those reported for 2014 or earlier.

A-14

Appendix A: Methodology for the 2022 General Aviation
and Part 135 Activity Survey
Data Collection Methods
Collecting Data from Owners/Operators of a Single Aircraft
Appendix B presents the materials used to conduct the 2022 survey. Figures B.1 through B.9
present the materials sent to owners/operators of a single aircraft. These include the survey
questionnaire, postcards and endorsement inserts, and the cover letters accompanying each of
the three survey mailings. Inserts and endorsements include a notice to individuals who started
but did not complete a web survey and an endorsement by Alaska aviation associations sent to
Alaska-based aircraft (Figures B.4 and B.5, respectively).
The survey data were collected from owners and operators of the sampled aircraft through two
modes—the web and mailings of the questionnaire. We implemented the web survey before
mailing paper surveys to maximize online survey response. We first sent the owners/operators
of sampled aircraft a postcard (mailed on February 24, 2023) or email (sent February 27, 2023)
inviting them to complete the survey on the Internet. All single-aircraft surveys received through
July 31 (online or by mail) were processed and included in analysis.
We mailed survey questionnaires to owners/operators of sampled aircraft three times during the
field period as well as a reminder/thank-you postcard between the first and second mailings,
and an end-of-field-period follow-up postcard. Each mailing was sent to owners or operators
who had not yet responded to the survey at that time or had not been assigned a final
disposition. We mailed the first questionnaire on March 24, 2023, followed by the
reminder/thank-you postcard on April 21, 2023. The second mailing was sent April 28, 2023.
The final postcard was mailed on June 3, 2023, and the final mailing was sent June 16, 2023.
Collecting Data from Owners/Operators of Multiple Aircraft
The survey materials sent to owners/operators of multiple aircraft are presented in Appendix B,
Figures B.10–B.14. These materials include the survey questionnaire and cover letters
accompanying each of the three survey mailings. In addition to the web and mail survey efforts,
telephone follow-up calls are made to nonresponding fleets to increase survey participation.
Owners or operators of multiple aircraft are sent an abbreviated survey form to minimize the
reporting burden. The form allows an operator to report a summary of activity for a group of
aircraft of a similar type instead of requiring the operator to complete a separate and longer
questionnaire for each individual aircraft. This survey form (Figure B.10) collects data on key
variables for major classes of aircraft (e.g., hours flown, how flown, fuel consumption, fractional
ownership, and number of landings). The form does not collect data on flight plans, fuel type,
landing gear, or avionics.
Data collection for owners or operators of multiple aircraft followed similar timing as that for
single aircraft. A web survey that matches the mail survey form is open throughout the field
period. We mailed survey questionnaires three times during the field period and sent a reminder
letter between the first and second mailings. Each mailing was sent to owners or operators of
multiple aircraft who had not yet responded to the survey and had not been assigned a final
disposition. The first survey mailing was sent March 3, 2023, and a second mailing posted on
April 7, 2023. These mailings were followed by a reminder letter and third mailing on June 2 and
June 16, 2023, respectively. Telephone contacts with nonresponding fleets began the week of
March 13, 2023, and continued through July 14, 2023. All large fleet surveys received through
July 31 were processed and included in analysis.
A-15

Appendix A: Methodology for the 2022 General Aviation
and Part 135 Activity Survey
Representation of Federally owned/-operated Aircraft
The US federal government operates several hundred aircraft in the GA fleet, but federal
agencies do not consistently respond to survey requests. We use data from the government’s
Federal Aviation Interactive Reporting System (FAIRS), which is managed by the General
Services Administration (GSA), to determine the number of active aircraft operated by federal
agencies and the hours flown. FAIRS does not include, or cannot share, information on aircraft
for all agencies; for example, activity by some agencies is not disclosed and law enforcement
activities may not be provided to FAIRS. Agencies are not required to report data to FAIRS, and
the representativeness of the data is unknown.
In 2022, the FAIRS data were again incomplete. No data were available for aircraft operated by
the Department of Homeland Security, and incomplete data were reported for four additional
agencies. Therefore, the 2022 survey results underestimate the size and overall activity of the
GA fleet, including estimates of public use activity and estimates for selected use categories.
Response Rate
The response rate is calculated following the American Association for Public Opinion Research
(AAPOR) guidelines. This professional association establishes standards, best practice
guidelines, and a code of ethics for survey researchers and research firms.14 We compute
Response Rate 1 (RR1), which AAPOR describes as the minimum response rate because it
retains all non-responding surveys in the denominator: We do not adjust the denominator by
estimating the number of non-responding aircraft of unknown eligibility that might be ineligible.
Specifically, the response rate is computed as the number of completed and partial surveys
returned divided by the total number of eligible aircraft in the sample using the following formula.
RR = (C + P) / (C + P) + (NR + INS + REF + PMR + UNK)
Where
RR = Response Rate
C = Completed survey
P = Partial survey
NR = No response
INS = Insufficient complete; a partial survey that is not sufficient to count as a complete
REF = Refused
PMR = Postmaster Returned, no new address

14

The American Association for Public Opinion Research. 2016. Standard Definitions: Final Dispositions
of Case Codes and Outcome Rates for Surveys. 9th edition. AAPOR.

A-16

Appendix A: Methodology for the 2022 General Aviation
and Part 135 Activity Survey
UNK = Unknown eligibility
The numerator is comprised of completed surveys and partial surveys that provide enough
information to be used for analysis. Partial surveys must include information on hours flown to
be analyzed.
In addition to completed and partial surveys, the denominator includes cases for which no
response was received, insufficiently completed surveys, refusals, surveys returned as
undeliverable by the US Postal Service, and cases of unknown eligibility. The last category
includes aircraft in which the owners cannot be identified or cannot report about aircraft activity
(e.g., owner is deceased, and the survivors cannot report on the aircraft activity, survey recipient
does not own the aircraft listed).
The denominator includes aircraft that were sold or destroyed during the survey year. The
survey collects data on flight activity for the portion of the year the aircraft was eligible to fly, and
data collection efforts attempt to identify and mail surveys to new owners.
The denominator excludes aircraft known not to be part of the general aviation fleet or known
not to be eligible to fly during the survey year. These are aircraft that were destroyed prior to the
survey year, operated primarily as an air carrier, operated outside the US, or exported overseas.
Table A.8 shows the number of completed surveys associated with each mailing and their
proportion of the total number of responses. Most responses (72 percent) were received online,
a result that has been consistent for many years. Seventeen percent of completed surveys were
returned from the first mailing, which is slightly lower than previous years when about 20
percent of completed surveys were returned in the first mailing. The second survey mailing
yielded 7.5 percent of all completed surveys, which is a 1 percentage point increase from 2021
and 2020. The third mailing resulted in almost 1,000 completed surveys or 3.2 percent of all
completed surveys. This is a decrease in both the number (1,442) and percentage (4.2 percent)
of completed surveys in 2021. However, the result is similar to the 2020 survey year when 818
of the completed surveys were returned at the third mailing and accounted for 2.4 percent of all
responses.15
Table A.8: Completed Surveys by Mailing
Mailing

Completes

% Total
Response

Internet

22,599

72.2

1st Mailing

5,337

17.1

2nd Mailing

2,348

7.5

3rd Mailing

996

3.2

31,280

100.0%

Overall

15

These tabulations reflect which survey form or mode a respondent completed, not the timing of receipt.
If a third survey mailing prompted an online survey submission, the complete is tallied as “Internet,” not
Mail 3. Likewise, if a respondent submits the Mail 1 survey form after receiving the second survey
mailing, the completed survey is tallied as Mail 1 (the survey form scanned as complete), not Mail 2.

A-17

Appendix A: Methodology for the 2022 General Aviation
and Part 135 Activity Survey
Table A.9 shows response rates by aircraft type. The overall response rate in 2022 is 38
percent. Participation is highest among multi-engine turbine rotorcraft, gliders, and experimental
amateur aircraft, all with response rates at or close to 50 percent. Like previous years, piston
rotorcraft and twin-engine turboprop aircraft have the lowest participation rates (24 to 27
percent).
Table A.9: Response Rate by Aircraft Type
Aircraft Type

Sample

Invalid
Sample

Completes

Response
Rate

30,751

525

11,760

38.9%

1 engine, 1–3 seats

6,770

175

2,520

38.2%

1 engine, 4+ seats

15,979

188

6,553

41.5%

2 engines, 1–6 seats

5,579

107

1,933

35.3%

2 engines, 7+ seats

2,423

55

754

31.8%

11,505

143

3,392

29.8%

1 engine

6,200

39

2,101

34.1%

2 engines, 1–12 seats

3,651

84

862

24.2%

2 engines, 13+ seats

1,654

20

429

26.3%

Fixed Wing - Turbojet

16,878

302

5,255

31.7%

Rotorcraft

12,111

309

4,672

39.6%

Piston

3,968

59

1,048

26.8%

Turbine: 1 engine

6,000

105

2,608

44.2%

Turbine: Multi-engine

2,143

145

1,016

50.9%

Other Aircraft

2,158

14

947

44.2%

Glider

1,080

9

528

49.3%

Lighter-than-air

1,078

5

419

39.0%

8,405

170

3,856

46.8%

Amateur

4,622

107

2,255

49.9%

Exhibition

1,382

23

553

40.7%

Experimental light-sport*

1,357

22

663

49.7%

Experimental Other

1,044

18

385

37.5%

3,205

19

1,401

44.0%

85,013

1,482

31,283

37.5%

Fixed Wing - Piston

Fixed Wing - Turboprop

Experimental

Special light-sport
Total

* Experimental light-sport includes aircraft with experimental airworthiness certification and light-sport
aircraft for which airworthiness certificates are not final.

A-18