The Safety of 

Experimental Amateur-Built Aircraft

Safety Study

NTSB/SS-12/01

PB2012-917001 National 

Transportation 

Safety Board
NTSB/SS-12/01

PB2012-917001

Notation 8413A

Adopted May 22, 2012

Safety Study

The Safety of Experimental Amateur-Built Aircraft

National 

Transportation 

Safety Board

490 L‘Enfant Plaza, SW

Washington, DC 20594
National Transportation Safety Board. 2012. The Safety of Experimental Amateur-Built Aircraft. Safety Study

NTSB/SS-12/01. Washington, DC.

Abstract: Experimental amateur-built (E-AB) aircraft represent nearly 10 percent of the U.S. general aviation 

fleet, but these aircraft accounted for approximately 15 percent of the total—and 21 percent of the fatal—U.S. 

general aviation accidents in 2011. Experimental amateur-built aircraft represent a growing segment of the 

United States‘ general aviation fleet—a segment that now numbers nearly 33,000 aircraft.

The National Transportation Safety Board undertook this study because of the popularity of E-AB 

aircraft, concerns over their safety record, and the absence of a contemporary and definitive analysis of E-AB 

aircraft safety. The study employed several different methods and data collection procedures to carefully 

examine this segment of U.S. civil aviation. This comprehensive approach resulted in a detailed characterization 

of the current E-AB aircraft fleet, pilot population, and associated accidents.

Areas identified for safety improvement include expanding the documentation requirements for initial 

aircraft airworthiness certification, verifying the completion of Phase I flight testing, improving pilots‘ access to 

transition training and supporting efforts to facilitate that training, encouraging the use of recorded data during 

flight testing, ensuring that buyers of used E-AB aircraft receive necessary performance documentation, and 

improving aircraft identification in registry records.

The National Transportation Safety Board (NTSB) is an independent federal agency dedicated to promoting aviation, railroad, 

highway, marine, pipeline, and hazardous materials safety. Established in 1967, the agency is mandated by Congress through the 

Independent Safety Board Act of 1974 to investigate transportation accidents, determine the probable causes of the accidents, issue 

safety recommendations, study transportation safety issues, and evaluate the safety effectiveness of government agencies involved in 

transportation. The NTSB makes public its actions and decisions through accident reports, safety studies, special investigation reports, 

safety recommendations, and statistical reviews.

Recent publications are available in their entirety on the Internet at <http://www.ntsb.gov>. Other information about available 

publications also may be obtained from the website or by contacting:

National Transportation Safety Board

Records Management Division, CIO-40

490 L’Enfant Plaza, SW

Washington, DC 20594

(800) 877-6799 or (202) 314-6551

NTSB publications may be purchased, by individual copy or by subscription, from the National Technical Information Service. To 

purchase this publication, order report number PB2012-917001 from:

National Technical Information Service

5301 Shawnee Road

Alexandria, Virginia 22312

(800) 553-6847 or (703) 605-6000

The Independent Safety Board Act, as codified at 49 U.S.C. Section 1154(b), precludes the admission into evidence or use of NTSB 

reports related to an incident or accident in a civil action for damages resulting from a matter mentioned in the report.
NTSB The Safety of Experimental Amateur-Built Aircraft

iii

Contents

Contents........................................................................................................................................ iii

Figures........................................................................................................................................... vi

Tables............................................................................................................................................ ix

Abbreviations and Definitions......................................................................................................x

Federal Aviation Administration (FAA) Documents and Regulations.................................. xii

Executive Summary................................................................................................................... xiv

Recommended Safety Actions..................................................................................................... xiv

What the NTSB Found in This Study ........................................................................................xv

Airworthiness Certification and Flight Testing of the E-AB Aircraft ...........................................xv

Availability and Quality of Transition Training .......................................................................... xvi

Guidance for Purchasers of Used E-AB Aircraft........................................................................ xvii

FAA and NTSB Data Limitations............................................................................................... xvii

1. Introduction...............................................................................................................................1

1.1 Background...............................................................................................................................4

1.1.1 The FAA‘s Definition of an E-AB Aircraft....................................................................4

1.1.2 Registration and Certification of an E-AB Aircraft........................................................6

1.1.3 Flight Testing During Phase I.........................................................................................8

1.1.4 Continuing Airworthiness of the E-AB Aircraft—Phase II ...........................................9

2. Accident Trends Across the Decade......................................................................................10

2.1 Aircraft Fleet and Activity......................................................................................................11

2.2 Accidents as a Function of Aircraft Age.................................................................................12

2.3 Comparison of Accident Characteristics ................................................................................14

2.4 Accident Pilot Demographics.................................................................................................17

2.5 Limitations in the Analysis of Retrospective Data .................................................................19

3. The Calendar Year 2011 Case-Series of E-AB Aircraft Accidents....................................20

3.1 Characteristics of the 224 E-AB Aircraft Accidents Occurring in 2011 ................................22

3.1.1 E-AB Aircraft Built by Owner Versus E-AB Aircraft Bought Used ...........................25

3.2 Accident Pilot Demographics.................................................................................................28

3.3 E-AB Aircraft Characteristics Requiring FAA Certificate Endorsements.............................32

3.4 Characteristics of Builders and Their Aircraft........................................................................33

3.5 Airworthiness Certification and Transition Training..............................................................34

3.5.1 E-AB Aircraft Purchased Used.....................................................................................35

3.6 Accidents as a Function of Airframe Hours ...........................................................................36

3.7 Accidents During Phase I Flight Testing................................................................................37

3.8 Accidents During the First Flight for E-AB Aircraft Built by Owner....................................39

3.9 Accidents During the First Flight for E-AB Aircraft Bought Used........................................40
NTSB The Safety of Experimental Amateur-Built Aircraft

iv

4. The EAA Survey of E-AB Aircraft Owners and Builders ..................................................43

4.1 Respondent Demographics .....................................................................................................45

4.2 E-AB Aircraft Makes..............................................................................................................50

4.3 E-AB Aircraft Characteristics Requiring FAA Certificate Endorsements.............................51

4.4 The E-AB Aircraft Building Process......................................................................................52

4.5 Transition Training .................................................................................................................58

4.6 Flight Test and Certification ...................................................................................................59

4.7 Owners of E-AB Aircraft Bought Used..................................................................................61

5. Analysis and Discussion..........................................................................................................64

5.1 Key Findings...........................................................................................................................64

5.2 Opportunities to Improve Safety During Initial Certification.................................................65

5.2.1 Airworthiness Certification of E-AB Aircraft ..............................................................65

5.2.2 Functional Test Requirements......................................................................................67

5.2.3 Flight Test Plan.............................................................................................................68

5.3 Opportunities to Improve Safety During Phase I Flight Test .................................................69

5.3.1 Phase I Flight Testing of E-AB Aircraft.......................................................................69

5.3.2 Accidents During Phase I Flight Testing......................................................................71

5.3.3 Loss of Control During Phase I Flight Testing.............................................................72

5.3.4 Phase I Test Pilot Qualifications...................................................................................72

5.3.5 Additional Persons Onboard During Phase I Flight Testing ........................................73

5.3.6 Completion of Phase I Flight Testing...........................................................................75

5.3.7 Use of Recorded Data for Phase I Flight Testing and Continued Airworthiness.........76

5.4 Training and Information to Prevent Loss of Control in Flight..............................................77

5.4.1 Transition Training .......................................................................................................77

5.4.2 Barriers to E-AB Aircraft Transition Training .............................................................78

5.4.3 Providing Information to Purchasers of Used E-AB Aircraft ......................................80

5.5 Accurate Identification of Amateur-Built Aircraft .................................................................82

6. Conclusions..............................................................................................................................85

6.1 Findings...................................................................................................................................86

7. Recommendations...................................................................................................................88

Appendix A: NTSB Aviation Accident Data Validation ..........................................................91

Appendix B: E-AB Aircraft Accident Supplementary Data Form .........................................95

Appendix C: Expanded Analysis of Amateur-Built Aircraft Accident Data, Calendar Year 

2011..............................................................................................................................................102

E-AB Aircraft Makes...................................................................................................................102

Appendix D: Amateur-Built Aircraft Survey..........................................................................107

Appendix E: Expanded Results of Experimental Aircraft Association Survey of E-AB 

Aircraft Owners and Builders. .................................................................................................120

Appendix F: Experimental Amateur-Built Study Cases, Calendar Year 2011 ...................125
NTSB The Safety of Experimental Amateur-Built Aircraft

v

Appendix G: Canadian Minister’s Delegate – Recreational Aviation Form C14E Fuel Flow 

Test Report .................................................................................................................................142

Appendix H: Special Light-Sport and Experimental Light-Sport Airworthiness Certificates 

and Sport Pilot Airmen Certificate ..........................................................................................143

Light-Sport Aircraft Definition....................................................................................................143
NTSB The Safety of Experimental Amateur-Built Aircraft

vi

Figures

Figure 1. Comparison of accident rates per 1,000 E-AB and non-E-AB aircraft for the 2001–2010 

period................................................................................................................................................2

Figure 2. Comparison of accident rates per 100,000 flight hours for E-AB and non-E-AB 

aircraft for the 2001–2010 period. ...................................................................................................3

Figure 3. The standard build kit for Van's RV-7 airplane...............................................................5

Figure 4. The quick-build kit of Van's RV-7 airplane. ...................................................................6

Figure 5. Registering and certifying an E-AB aircraft, according to FAA AC 20-27G. ................7

Figure 6. Number of active E-AB and non-E-AB aircraft annually from 2001 to 2010. .............11

Figure 7. FAA-reported number of hours flown for E-AB and non-E-AB aircraft annually 

from 2001 through 2010. ...............................................................................................................12

Figure 8. Cumulative distribution of airframe hours of E-AB and non-E-AB aircraft involved 

in accidents from 2001 through 2010; 8,072 accident aircraft with available airframe hours 

information.....................................................................................................................................13

Figure 9. Distribution of accidents involving E-AB and non-E-AB aircraft involving the 

10 most common CAST/ICAO occurrence categories from 2001 through 2010..........................15

Figure 10. Distribution of fatal accidents involving E-AB and non-E-AB aircraft involving 

the 10 most common occurrence categories from 2001 through 2010..........................................16

Figure 11. Median accident pilot age for E-AB and non-E-AB aircraft, 2001–2010...................18

Figure 12. Locations of the 224 E-AB aircraft accidents occurring in the United States 

during calendar year 2011..............................................................................................................21

Figure 13. CAST/ICAO occurrence categories for E-AB accident aircraft, 2011. ......................24

Figure 14. Phase of flight for the 227 aircraft involved in the 2011 E-AB aircraft accidents. .....25

Figure 15. CAST/ICAO occurrence categories for E-AB aircraft built by owner versus 

E-AB aircraft bought used, 2011. ..................................................................................................26

Figure 16. Years since certification for E-AB aircraft built by the owner versus those 

bought used. ...................................................................................................................................27

Figure 17. Years that the accident E-AB aircraft has been owned by the current owner. ............28

Figure 18. Age distributions of accident pilots who had built their E-AB aircraft and those 

who had bought them used. ...........................................................................................................29
NTSB The Safety of Experimental Amateur-Built Aircraft

vii

Figure 19. Highest pilot certificate for accident pilots who bought used E-AB aircraft and 

those who built their E-AB aircraft................................................................................................30

Figure 20. Total flight hours for accident pilots who built their E-AB aircraft and those who 

bought used E-AB aircraft (based on data from 175 of 227 accident pilots). ...............................31

Figure 21. Total E-AB aircraft flight hours for those who built their aircraft and those who 

bought used aircraft (based on data from 155 of 227 accident pilots)...........................................32

Figure 22. Cumulative proportion of built-by-owner and bought used E-AB aircraft as a 

function of airframe hours. ............................................................................................................37

Figure 23. CAST/ICAO occurrence category for the 2011 E-AB accidents during Phase I 

of the flight test program................................................................................................................38

Figure 24. Airframe hours at time of accident..............................................................................39

Figure 25. Method of E-AB aircraft ownership by type of aircraft. .............................................44

Figure 26. Years since certification for E-AB aircraft built by the respondent versus E-AB 

aircraft bought used by respondents (based on 4,082 survey responses). .....................................45

Figure 27. Respondent age by method of E-AB aircraft ownership.............................................46

Figure 28. Highest pilot certificate by method of E-AB aircraft ownership.................................47

Figure 29. Years of pilot experience by method of E-AB aircraft ownership..............................48

Figure 30. Total Flight Hours by E-AB aircraft method of ownership.........................................49

Figure 31. Total E-AB aircraft flight hours by method of ownership. .........................................50

Figure 32. Type Building Project by E-AB aircraft method of ownership...................................51

Figure 33. Engine choices among E-AB aircraft builders. ...........................................................54

Figure 34. The location at which the E-AB aircraft was, or is being, built. .................................56

Figure 35. Sources of builder assistance.......................................................................................57

Figure 36. Individuals performing inspections during the building process.................................58

Figure 37. Issuer of airworthiness certificates reported by 2,597 of the 3,103 respondents 

who had completed their E-AB aircraft.........................................................................................60

Figure 38. Sources of assistance in developing Phase I test plans for the 3,103 respondents 

who had built their E-AB aircraft. .................................................................................................61
NTSB The Safety of Experimental Amateur-Built Aircraft

viii

Figure 39. Total hours of flight experience for respondents who purchased used E-AB 

aircraft (1,132 of 1,151 reporting this information).......................................................................63

Figure A1. Changes in the annual U.S. civil general aviation accident and fatal accident 

records for E-AB aircraft, 2001–2010. ..........................................................................................92

Figure A2. Revised amateur-built aircraft accident rate following NTSB accident data 

validation, 2001–2010....................................................................................................................93

Figure A3. Revised amateur-built aircraft fatal accident rate following NTSB accident data 

validation, 2001–2010....................................................................................................................94

Figure C1. Types of E-AB accident aircraft built by owners and bought as used, 2011............102

Figure C2. Type of E-AB aircraft building project for aircraft built by owners and those 

bought used. .................................................................................................................................103

Figure C3. E-AB accident aircraft makes built by owners.........................................................104

Figure C4. E-AB accident aircraft makes bought used. .............................................................105

Figure C5. Number of previous owners for accident E-AB aircraft bought used. .....................106

Figure E1. Kit manufacturers reported by survey respondents. .................................................120

Figure E2. Kit models for the Van's, Lancair, Glasair and Zenith aircraft kits reported in 

the survey.....................................................................................................................................121

Figure E3. Plans-built aircraft designs reported by survey respondents.....................................122

Figure E4. Years to complete for the 3,095 respondents reporting this information. ................123

Figure E5. Total build hours for the 1,648 respondents reporting this information. ..................124

Figure H1. Chart illustrating an increase in the proportion of accident aircraft meeting the 

weight limitation of light-sport aircraft, following the 2004 effectiveness date of the 

light-sport aircraft and sport pilot rule.........................................................................................150

Figure H2. Chart illustrating an increase in the proportion of accident pilots of E-AB 

aircraft without a First, Second, or Third Class medical following the 2004 effective date 

of the light-sport aircraft and sport pilot rule...............................................................................151
NTSB The Safety of Experimental Amateur-Built Aircraft

ix

Tables

Table 1. Accident aircraft displaying design features that would require specific training or 

logbook endorsements. ..................................................................................................................33

Table 2. Characteristics of accident E-AB aircraft built by owners..............................................34

Table 3. Characteristics of accident E-AB aircraft bought used...................................................36

Table 4. Characteristics of the 10 accidents in 2011 that occurred during the first test flight 

of the newly built E-AB aircraft. ...................................................................................................40

Table 5. Accidents involving the first flight after purchase of E-AB aircraft bought used. .........42

Table 6. Aircraft design features and corresponding pilot certificate endorsements. ...................52

Table 7. Principal characteristics of the kit-built, plans-built and original design E-AB 

aircraft built or being built by survey respondents. .......................................................................55

Table 8. Source of transition training reported by respondents who had completed their 

E-AB aircraft..................................................................................................................................59

Table 9. Characteristics of the E-AB aircraft bought used by survey respondents.......................62
NTSB The Safety of Experimental Amateur-Built Aircraft

x

Abbreviations and Definitions

Aviation Safety Inspector (ASI) Federal Aviation Administration (FAA) employees who 

provide oversight of operations or maintenance in 

commercial or general aviation. Maintenance safety 

inspectors hold an FAA Mechanic Certificate and have 

experience involving maintenance and repair of airframes, 

powerplants, and systems. They have responsibility for 

certifying airworthiness and the issuing of airworthiness 

certificates.

Commercial Assistance 

Provider

An individual or corporation that assists in the building of 

an E-AB in exchange for compensation.

Demonstration Flight Pre-project test flights provided by kit manufacturers or 

other E-AB owners.

Designated Airworthiness 

Representative (DAR)

An individual appointed by the FAA to perform 

examination, inspection, and testing services necessary to 

the issuance of certificates. DARs authorized to issue 

special airworthiness certificates for the purpose of 

operating amateur-built aircraft must possess current 

knowledge relating to the fabrication, assembly, and 

operating characteristics of amateur-built aircraft. DARs 

are not FAA employees, and they may charge for their 

services.

Experimental Aircraft

Association (EAA)

The EAA was established in 1953 by a small group of 

individuals interested in building their own aircraft. It has 

grown to an organization of nearly 170,000 members that 

exists to promote sport aviation and amateur builders. The 

EAA also provides a variety of technical instruction and 

support programs for aircraft owners and builders. Its 

headquarters are in Oshkosh, Wisconsin.

Experimental Aircraft 

Association (EAA) Flight 

Advisor

An EAA member volunteer who assists the owner/builder 

or buyer of a used E-AB plan the first flight, find an 

instructor, and suggest additional training in the aircraft.

Experimental Aircraft 

Association (EAA) Technical 

Counselor

An EAA member volunteer who is an experienced aircraft 

builder, restorer, or mechanic, and who provides builders 

with the technical advice on building or restoring E-AB 

aircraft.
NTSB The Safety of Experimental Amateur-Built Aircraft

xi

Experimental Amateur-Built

(E-AB) Aircraft

An aircraft, the major portion of which has been 

assembled by a person, or persons, who undertook the 

project for the sole purpose of self-education or 

recreation.

General Aviation Operations An aviation operation that is operating under any part of 

the Federal Aviation Regulations, except Title 14 Code of 

Federal Regulations (CFR) Parts 121, 135, or 129.

Kit Built E-AB An aircraft that is constructed from a manufactured kit 

that may include some major sub-assemblies and preassembled parts. These kits still require that the amateur 

builder perform more than one-half of the fabrication and 

assembly tasks in order to meet the "51 percent" rule.

Letter of Deviation Authority 

(LODA)

A letter issued by the Administrator of the FAA that 

allows the owner of an E-AB to offer his/her aircraft for 

compensation or hire for the purpose of flight instruction. 

Original Design E-AB An aircraft constructed based on plans designed 

completely by the owner/builder without the purchase of 

major sub-assemblies or pre-assembled kit components.

Phase I Flight Test The flight testing phase following issuance of a special 

airworthiness certificate for operation of an amateur-built 

aircraft. Operating limitations issued for this phase restrict 

operation to a sparsely populated geographic area and 

prohibit the carrying of passengers. 

Phase II Flight Phase II begins when the builder/owner certifies that 

flight testing has been completed. The geographic 

limitations are generally relaxed and non-revenue 

passengers may be carried.

Plans Built E-AB An aircraft constructed from raw materials according to

published blueprints or plans prepared by an individual or 

commercial entity other than the owner/builder.

Transition Training The training a pilot receives when beginning to fly an 

unfamiliar aircraft. This training is meant to familiarize 

the pilot with the systems and structures of the aircraft to 

a point that he/she can competently operate the aircraft on 

his/her own.
NTSB The Safety of Experimental Amateur-Built Aircraft

xii

Federal Aviation Administration (FAA) 

Documents and Regulations

FAA Advisory Circulars (AC)

AC 20-27G Titled, Certification and Operation of Amateur-Built Aircraft, this AC 

provides information about FAA regulations and procedures for 

airworthiness certification of equipment for the purpose of operating 

amateur-built aircraft.

AC 90-89A Titled, Amateur-Built Aircraft and Ultralight Flight Testing 

Handbook, this AC provides suggestions and safety-related 

recommendations to assist amateur and ultra-light builders in 

developing individualized aircraft flight test plans. 

AC 90-109 Titled, Airmen Transition to Experimental or Unfamiliar Airplanes, 

this AC provides information and guidance to owners and pilots of 

experimental airplanes and to flight instructors who teach in 

experimental airplanes. This AC also contains training 

recommendations for pilots of experimental airplanes in a variety of 

groupings based on performance and handling characteristics.

FAA Orders

Order 8130.2G This order establishes FAA procedures for airworthiness certification 

of aircraft and related equipment. The procedures contained in this 

order apply to FAA ASIs, and persons or organizations with delegated 

authority to issue airworthiness certificates and related approvals.

Order 8130.35 This order created the Amateur-Built Aircraft National Kit Evaluation 

Team (NKET) and established methodology to determine whether 

kits, as manufactured, allow the builder to meet the major portion 

requirement.

Order 8900.1 This order stipulates that aircraft holding an experimental certificate 

may not be used to provide flight training for compensation or hire, 

unless a Letter of Deviation Authority is issued.

Title 14 Code of Federal Regulations (CFR)

14 CFR 21.191(g) FAA regulation establishing the experimental airworthiness certificate 

for the purpose of operating amateur-built aircraft, including the major 

portion build requirement of amateur-built aircraft.
NTSB The Safety of Experimental Amateur-Built Aircraft

xiii

14 CFR 21.193 FAA regulation prescribing the procedures and document submission 

requirements for applicants for an experimental airworthiness 

certificate.

14 CFR 47.31 FAA regulation prescribing requirements for the registration or reregistration of U.S. civil aircraft.

14 CFR 65.104 FAA regulation prescribing the eligibility, privileges, and limitations 

of the FAA repairman certificate for the primary builder of an 

amateur-built aircraft.

14 CFR 91.319 FAA regulation prescribing operating limitations of aircraft having 

experimental airworthiness certificates.
NTSB The Safety of Experimental Amateur-Built Aircraft

xiv

Executive Summary

Experimental amateur-built (E-AB) aircraft represent nearly 10 percent of the U.S. 

general aviation fleet, but these aircraft accounted for approximately 15 percent of the total—and 

21 percent of the fatal—U.S. general aviation (GA) accidents in 2011. Experimental 

amateur-built aircraft represent a growing segment of the United States‘ general aviation fleet—a 

segment that now numbers nearly 33,000 aircraft. 

The National Transportation Safety Board (NTSB) undertook this study because of the 

popularity of E-AB aircraft, concerns over their safety record, and the absence of a contemporary 

and definitive analysis of E-AB aircraft safety. The study employed several different methods 

and data collection procedures to carefully examine this segment of U.S. civil aviation. This 

comprehensive approach resulted in a detailed characterization of the current E-AB aircraft fleet, 

pilot population, and associated accidents. 

Four sources of data formed the basis of this study. First, the NTSB performed a 

retrospective analysis of accident and activity data over the last decade to compare the accident 

experience of E-AB aircraft with that of similar non-E-AB aircraft used in similar GA flight 

operations. Second, the NTSB conducted in-depth investigations of all E-AB aircraft accidents 

during 2011, which provided a case-series of accidents for more detailed analysis. Third, a broad 

survey of the community of aircraft owners and builders was conducted by the Experimental 

Aircraft Association (EAA) in July and August 2011, and the data were made available to the 

NTSB for analysis to understand the population of E-AB aircraft builders and owners. Finally, 

discussions with EAA representatives, Federal Aviation Administration (FAA) officials, 

E-AB aircraft builders and owners, kit manufacturers, and representatives of E-AB aircraft type 

clubs provided insights on E-AB aircraft safety issues and solutions. 

Recommended Safety Actions

In response to the findings of this study, the National Transportation Safety Board issued

12 recommendations to the Federal Aviation Administration and 4 recommendations to the 

Experimental Aircraft Association. The recommendations include expanding the documentation 

requirements for initial aircraft airworthiness certification, verifying the completion of Phase I 

flight testing, improving pilots‘ access to transition training and supporting efforts to facilitate 

that training, encouraging the use of recorded data during flight testing, ensuring that buyers of 

used E-AB aircraft receive necessary performance documentation, and improving aircraft 

identification in registry records.
NTSB The Safety of Experimental Amateur-Built Aircraft

xv

What the NTSB Found in This Study

The study compared the accident experience of E-AB aircraft with that of similar 

non-E-AB general aviation aircraft over the last decade. A detailed analysis was also conducted 

of the 224 accidents, involving 227 E-AB aircraft, that occurred during 2011.1These analyses 

revealed the following factors defining E-AB aircraft accidents: 

E-AB aircraft account for a disproportionate number of total accidents and an even 

more disproportionate share of fatal accidents when compared with similar non-E-AB 

aircraft conducting similar flight operations.

Accident analyses indicate that powerplant failures and loss of control in flight are the 

most common E-AB aircraft accident occurrences by a large margin and that accident 

occurrences are similar for both new and used aircraft.

Structural failures have not been a common occurrence among E-AB aircraft.

In comparison with similar non-E-AB aircraft, a much higher proportion of accidents 

involving E-AB aircraft occur early in the operational life of the aircraft. 

A similarly large proportion of E-AB aircraft accidents occur shortly after being 

purchased by a subsequent owner. For example, 14 of the 224 study accidents 

during 2011 occurred during the first flight by a new owner of a used E-AB aircraft.

Through further analysis of the accident record and the results of an EAA survey of 

E-AB aircraft owners and builders, the study also found:

The majority of E-AB aircraft are now built from commercial kits, rather than from 

purchased plans or original designs. 

Pilots of E-AB aircraft, whether involved in accidents or not, have similar, or higher, 

levels of total aviation experience than pilots of non-E-AB aircraft engaged in similar 

general aviation operations. 

Pilots of E-AB accident aircraft, on average, had significantly less flight experience in 

the type of aircraft they were flying than pilots of non-E-AB aircraft. 

Finally, study analyses identified the following key issue areas to explain these findings 

and recommended actions to improve E-AB aircraft safety. 

Airworthiness Certification and Flight Testing of the E-AB Aircraft

E-AB aircraft safety is largely managed by the community of E-AB aircraft builders, 

owners, and kit manufacturers rather than by FAA regulatory requirements. A primary focus of 

 1

Three of the 224 accidents involved collisions between two E-AB aircraft, accounting for a total of 227 E-AB 

aircraft.
NTSB The Safety of Experimental Amateur-Built Aircraft

xvi

FAA regulations governing the E-AB aircraft building process seeks to ensure that the major 

portion of the construction work is done by the builder. Airworthiness certificates are granted to 

the E-AB aircraft builder by the FAA based only on a review of documentation and a one-time 

inspection of the aircraft after it has been completed. Unlike foreign civil aviation authorities‘ 

standards, there is no requirement for pre-approval of the project or in-process inspections of 

materials and workmanship. However, the study found that a large proportion of E-AB aircraft 

accidents involving loss of engine power could be reduced by requiring documentation of a 

functional test of aircraft fuel system as part of the initial airworthiness certification. 

As part of the airworthiness certification process, E-AB aircraft are assigned operating 

limitations specifying how and where the aircraft can be flown. E-AB aircraft operating 

limitations specify two phases of operation: Phase I, which is applicable to the flight test period 

and Phase II, which governs normal operations once testing is complete. Builders of E-AB are 

required to certify that the flight test has been completed with an entry in the aircraft logbook.

Although FAA guidance materials are explicit in advising the builder that the objective of the 

flight test is to carefully map the performance envelope of the aircraft and develop an aircraft 

flight manual, neither a flight test plan nor documentation of its accomplishment, in the form of 

an aircraft flight manual, are required to be submitted to, reviewed, or accepted by an FAA 

Aviation Safety Inspector (ASI) or FAA Designated Airworthiness Representative (DAR). The 

study found that verifying the completion of Phase I flight testing through a review of the flight 

test records and resulting aircraft flight manual by an FAA ASI or DAR could ensure the 

adequacy of E-AB aircraft flight testing prior to engaging in normal Phase II flight operations.

Glass cockpit avionics, which are capable of recording aircraft and engine performance 

data, have been shown to be useful in the accomplishment of flight test objectives. A majority of 

EAA survey respondents who were in the process of building their E-AB aircraft equipped their 

aircraft with such instrumentation, and 35 percent of the owner-built E-AB aircraft involved in 

accidents during 2011 were equipped with glass cockpit avionics. The study found that FAA 

guidance does not address the use of data recordings from avionics or other electronic devices as 

part of an E-AB aircraft flight test program, potentially limiting the use of an important data 

source in a critical aspect of the demonstration of the E-AB aircraft‘s airworthiness.

The Phase I flight test period is uniquely challenging for pilots who must learn the 

handling characteristics of an unfamiliar aircraft while also managing the challenges of the flight 

test environment and procedures. Of the 224 E-AB aircraft accidents during 2011 included in 

this study, 32 included aircraft in the Phase I flight testing period, suggesting that pilots would 

benefit from additional training in the safe performance of E-AB aircraft flight test operations.

Current Phase I operating limitations preclude anyone ―not essential to the purpose of flight‖ 

from flying in the aircraft during flight testing. The study determined that consideration should 

be given to permit an additional pilot in cases where test circumstances could be performed more 

safely and more effectively with a second qualified pilot on board.

Availability and Quality of Transition Training 

Both the accident analyses and extensive discussions with EAA members, kit 

manufacturers, and E-AB aircraft builders emphasized the importance of the builder receiving 

appropriate and sufficient transition training to develop proficiency with the new type of aircraft 
NTSB The Safety of Experimental Amateur-Built Aircraft

xvii

prior to flying his/her E-AB aircraft. These discussions identified challenges in finding 

appropriate training aircraft and instructors. Their scarcity, in part, is a result of the difficulty in 

obtaining an exception to the FAA regulation prohibiting a qualified instructor who owns an 

E-AB aircraft from charging students for instruction in that aircraft. The study determined that 

pilots would benefit from improved guidance regarding transition training in E-AB aircraft.

Guidance for Purchasers of Used E-AB Aircraft

Purchasers of used E-AB aircraft face particular challenges in transitioning to the new 

aircraft, which are aggravated by the absence, in many cases, of the sort of comprehensive 

aircraft flight manual that would be available to the owner of a non-E-AB aircraft. The study 

found that, because there is no review of flight test results, not all builders create an aircraft 

flight manual or performance documentation for their aircraft. Absent that documentation, the 

purchaser of a used E-AB aircraft is not provided with sufficient information to understand the 

aircraft‘s controllability throughout all maneuvers, to detect any hazardous operating 

characteristics, or to understand emergency procedures.

FAA and NTSB Data Limitations

Finally, the study identified shortcomings in the FAA‘s Civil Aircraft Registry that affect

the conduct of safety analyses and hamper notification of aircraft owners when aircraft- or 

engine-specific safety issues are discovered.
NTSB The Safety of Experimental Amateur-Built Aircraft

1

1. Introduction

Experimental amateur-built (E-AB) aircraft represent a significant, and growing, 

proportion of the General Aviation fleet in the United States and around the world. According to 

the FAA‘s 2010 General Aviation and Part 135 Activity Survey, they account for nearly 

10 percent of general aviation aircraft, and 4 percent of the hours flown in general aviation.

Despite a decade-long decline in overall general aviation flight activity, the E-AB segment has 

grown both in numbers of aircraft and flight activity during this period. 

E-ABs have experienced a disproportionate number of accidents relative both to their 

proportion of the general aviation fleet, and their share of general aviation flight activity. The 

overall E-AB aircraft accident rate per 1,000 aircraft is nearly twice that of comparable2

non-E-AB aircraft, and the fatal accident rate is between 2.5 and 3 times higher. Figure 1 shows

that these differences have remained relatively constant across the last decade.

Considered as a function of hours of flight activity, the accident rate disparity between 

E-AB aircraft and non-E-AB aircraft has also been consistently wide. The total E-AB aircraft

accident rate per 100,000 flight hours was between 2.5 and 3 times that of non-E-AB aircraft 

between 2001 and 2010, and the fatal accident rate was approximately 4 times greater, on 

average, than that of non-E-AB aircraft. The comparative accident rates per 100,000 flight hours 

are shown in Figure 2. 

 2

The comparison group selected to most closely match E-AB aircraft included all single-engine, 

piston-powered airplanes; piston-powered helicopters; balloons; and gliders that were not certificated as 

experimental amateur-built aircraft.
NTSB The Safety of Experimental Amateur-Built Aircraft

2

Figure 1. Comparison of accident rates per 1,000 E-AB and non-E-AB aircraft for the 

2001-2010 period.

9.07

5.54

2.26

0.91

0

2

4

6

8

10

12

14

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Accidents per 1,000 Aircraft

Calendar Year

Total and Fatal Accident Rates per 1,000 Aircraft, 

2001–2010

E-AB total Non-E-AB total E-AB fatal Non-E-AB fatal
NTSB The Safety of Experimental Amateur-Built Aircraft

3

Figure 2. Comparison of accident rates per 100,000 flight hours for E-AB and non-E-AB aircraft 

for the 2001–2010 period.

These differences in accident risk for E-AB aircraft have been widely noted in the 

aviation community. Former FAA Administrator Randy Babbitt told a Sun‘N Fun audience3 

in 2010, that amateur-built aircraft have ―too high an accident rate‖, and that ―they account for 

10 percent of the GA fleet, but 27 percent of accidents.‖ Aviation analysts such as Wanttaja,

4,5

have also recognized the elevated accident risk for amateur-built aircraft, while pointing out 

flaws in both registration and accident data that may affect these analyses.

Believing there to be a strong basis for a safety concern, the National Transportation 

Safety Board (NTSB) undertook this study to identify, and provide an in-depth assessment of, 

the salient issues that affect this important segment of the U.S. general aviation fleet. A 

necessary context for this study is the unique regulatory environment, within U.S. civil aviation, 

in which these aircraft are built and operated.

 3

Grady, Mary ―FAA Administrator Babbitt Takes in Sun‘N Fun,‖ April 14, 2010, AVWeb.

4 Wanttaja, Ron, Homebuilt Aircraft Safety: 1998-2006, Kitplanes, October, 2008.

5 Wanttaja, Ron, Amateur-Built Accident Report: Reviewing the Past Five Years, EAA Sport Aviation, Vol. 6, 

No. 4, April, 2012, 30–35.

21.17

9.49

5.27

1.56

0

5

10

15

20

25

30

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Accidents per 100,000 Flight Hours

Calendar Year

Total and Fatal Accident Rates per 100,000 Flight 

Hours, 2001–2010

E-AB total Non-E-AB total E-AB fatal Non-E-AB fatal
NTSB The Safety of Experimental Amateur-Built Aircraft

4

1.1 Background

Most of the aircraft used in general aviation operations in the United States are built 

under a type certificate issued to the manufacturer upon demonstration of compliance with 

14 Code of Federal Regulation (CFR) Part 23. General aviation operations also include, 

however, aircraft within one of several categories of the type of special airworthiness certificate6

known as experimental. Most experimental airworthiness certificates are issued to amateur-built 

aircraft. These aircraft are built, or assembled, by hobbyists or amateur builders. 

1.1.1 The FAA’s Definition of an E-AB Aircraft

The FAA first identifies an aircraft as amateur-built when it is registered with the FAA 

Registration Branch.7FAA regulations allow for aircraft constructed from an amateur builder‘s 

original design, purchased plans, or pre-fabricated kit, to be registered as an E-AB aircraft

provided that the builder (or builders) demonstrate that he or she has fabricated or assembled 

over one-half of the aircraft. While FAA Advisory Circular (AC) 20-27G provides general 

guidance to amateur builders regarding the planning and construction of an E-AB aircraft and 

refers builders to technical support available from the EAA and others, its principal focus is to 

communicate and ensure compliance with the ―major proportion‖ or ―51-percent‖ rule, namely:

The major portion of the aircraft is defined as more than 50 percent of the 

fabrication and assembly tasks, commonly referred to as the ―51-percent rule.‖

For example, an amateur-built kit found on the FAA List of Amateur-Built 

Aircraft Kits has 40 percent of the fabrication/assembly completed by the kit 

manufacturer. In order to be eligible for an experimental amateur-built 

airworthiness certificate, and per the major portion rule, the fabrication and 

assembly tasks that may be contracted out (for hire) to another individual (or 

builder/commercial assistance center) needs to be less than 10 percent.

The experimental amateur-built category was first adopted in Civil Aeronautics 

Manual 1

8

in 1952, and early E-AB aircraft were primarily the original designs of their builders 

or aircraft built from plans shared between builders. The first kits, which consisted of 

factory-fabricated components and sub-assemblies, were introduced in the 1970s and kit-built 

E-AB aircraft now constitute the largest proportion of experimental aircraft. The FAA publishes, 

on its website, a listing of kits that have been evaluated and found eligible in meeting the  ̳major 

portion‘ requirement of 14 CFR 21.191(g). The FAA also issued Order 8130.35, which created 

the Amateur-Built Aircraft National Kit Evaluation Team (NKET) and established a standard 

 

6

Per 14 CFR 21.175(b), the special airworthiness certificate categories include primary, restricted, limited, 

light-sport, and provisional airworthiness certificates, special flight permits, and experimental certificates. The 

special light-sport and experimental light-sport certificates were added in 2004. Light-sport aircraft are 

manufactured, or built from kits, that conform to the ASTM International consensus standard rather than a type 

certificate. Appendix G contains further descriptions of light-sport aircraft.

7

Ford, Edsel W. Jr. ―Breaking the Code,‖ FAA Aviation News, Sept 22, 2011.

8

U.S. Department of Commerce, Civil Aeronautics Administration, Civil Aeronautics Manual 1: Certification, 

Identification and Marking of Aircraft and Related Products, October, 1952.
NTSB The Safety of Experimental Amateur-Built Aircraft

5

methodology to determine whether kits, as manufactured, allow the amateur builder to meet the 

major portion requirement. There is no FAA evaluation of the airworthiness of kits.

Some kit manufacturers offer both standard kits and so-called quick-build kits to reduce 

the time required to complete the E-AB aircraft project. For example, Van‘s Aircraft Company,9

offers both standard build and quick-build kits for several of its models and claims that 

quick-build kits cut building time by 35–40 percent. Figure 3 shows the standard Van‘s kit for its

RV-7, a 20-foot, 4-inch-long, two-seat, tailwheel airplane with a wing span of 25 feet. Figure 4

shows the quick-build kit for the same airplane. The FAA lists both as meeting the ―51-percent‖

rule. 

Figure 3. The standard build kit for Van's RV-7 airplane.

 9

http://www.vansaircraft.com/public/kit-qb.htm.
NTSB The Safety of Experimental Amateur-Built Aircraft

6

Figure 4. The quick-build kit of Van's RV-7 airplane.

1.1.2 Registration and Certification of an E-AB Aircraft

Figure 5, from FAA AC 20-27G, details the steps a builder must follow to register and 

certify an E-AB aircraft. This AC provides general advice to the builder regarding FAA 

regulations and invites the builder to contact the applicable Manufacturing Inspection District 

Office or Flight Standards District Office if he/she requires further guidance. There is no 

requirement for pre-registration of the aircraft building project, and the builder is advised to 

complete the registration forms for the new aircraft 60 to 120 days before the construction is 

expected to be completed.
NTSB The Safety of Experimental Amateur-Built Aircraft

7

Figure 5. Registering and certifying an E-AB aircraft, according to FAA AC 20-27G.

As a part of his/her registration application, the builder must provide a notarized 

Affidavit of Ownership for Experimental Aircraft (AC Form 8050-88), which identifies the 

aircraft and engine (if the aircraft is powered) and records the builder‘s attestation that he/she has 

complied with the major portion rule. No inspection of the aircraft is conducted at this stage.
NTSB The Safety of Experimental Amateur-Built Aircraft

8

Amateur-built aircraft do not receive FAA type design approval but instead are issued a 

special airworthiness certificate in the experimental category following submission of an 

Application for Airworthiness Certificate10 and the successful completion of an FAA 

airworthiness inspection and documentation review, which is conducted either by an ASI or a

DAR. In addition to satisfying the major portion requirement, E-AB builders must provide 

evidence that the aircraft complies with acceptable aeronautical standards and practices. The ASI 

or DAR will conduct an inspection of the completed aircraft as well as a review of the builder‘s 

documentation of the building process, which may include construction logs, photographs, and 

reports of inspections by EAA Technical Counselors.

Following successful completion of the inspection of the aircraft and the documentation 

review, the ASI or DAR will issue an airworthiness certificate11 and a set of operating limitations 

that are unique to the aircraft and become part of the special airworthiness certificate. Two sets 

of operating limitations are typically established at the time the airworthiness certificate is 

issued. Phase I operating limitations are associated with an initial flight testing period during 

which the aircraft must be subjected to operational testing to demonstrate that it meets the 

requirements of 14 CFR 91.319(b) (i.e., the aircraft is controllable throughout its normal range of 

speeds and throughout all the maneuvers to be executed and the aircraft has no hazardous 

operating characteristics or design features). Once the Phase I period has been completed, the

Phase II operating limitations go into effect for an indefinite period, unless a major modification 

is made to the aircraft. Therefore, Phase I operating limitations can be described as applicable to 

flight testing, and Phase II can be described as normal operation of an E-AB aircraft. 

1.1.3 Flight Testing During Phase I

FAA Order 8130.2G provides guidance for applicants to show compliance with 

14 CFR 91.319(b) after the airworthiness certificate is issued by developing and executing an 

explicit flight test program in accordance with FAA AC 90-89A

12 or comparable guidance. The 

order identifies two purposes for this test program:

(1) They ensure the aircraft has been adequately tested and determined to be safe to 

fly within the aircraft‘s flight envelope.

(2) The flight test data is used to develop an accurate and complete aircraft flight 

manual and to establish emergency procedures.

The length of this Phase I flight test period is not established by regulation, but 

FAA Order 8130.2G recommends a minimum Phase I test period of 25 hours for aircraft 

equipped with type-certificated engine/propeller combinations and a minimum of 40 hours for 

aircraft with non-type-certificated engine, propeller, or engine/propeller combinations.13 There is 

 10 FAA Form 8130-6, Application for Airworthiness Certificate.

11 FAA Form 8130-7, Special Airworthiness Certificate.

12 Federal Aviation Administration Advisory Circular, AC 90-89A. Amateur-Built Aircraft and Ultralight 

Flight Testing Handbook, FAA, Washington, D.C. 1995.

13 Type-certificated engines and propellers have been manufactured according to an FAA type certificate, 

non-certificated engines and propellers have not.
NTSB The Safety of Experimental Amateur-Built Aircraft

9

no requirement that the test plan be presented to, or reviewed by, the FAA when the 

airworthiness certificate and Phase I operating limitations are issued. Operating limitations 

issued with the airworthiness certificate restrict the Phase I test flights to a geographic area that 

avoids populated areas or busy airspace. During Phase I, only those persons essential to safe 

flight may be carried in the aircraft. Usually this is interpreted to preclude other than solo 

operations. The completion of Phase I flight test requirements is self-certified by the builder with 

an entry in the aircraft logs. There is no requirement for the FAA to review or confirm the flight 

test data intended to demonstrate that the aircraft was ―safe to fly within the aircraft‘s flight 

envelope‖ or that ―an accurate and complete aircraft flight manual‖ had been developed.

1.1.4 Continuing Airworthiness of the E-AB Aircraft—Phase II

After Phase I flight testing is certified as complete by the E-AB aircraft owner, the more 

liberal Phase II operating limitations become effective. In Phase II, the geographical restrictions 

are relaxed and non-revenue passengers are permitted. Ordinarily the Phase II operating 

limitations are assigned for an unlimited time period. An experimental amateur-built aircraft may 

be piloted in Phase II by individuals holding a private pilot or higher certificate.14 The operating 

limitations of Phase II require an annual condition inspection, which is recorded in the aircraft 

logbook. Unlike type-certificated aircraft, there is no restriction on who may perform 

maintenance on an E-AB aircraft, other than major changes. The annual condition inspection 

requirement may be carried out by the aircraft builder, if he/she holds a repairman certificate15

for that aircraft. Otherwise the condition inspection must be performed by an appropriately-rated 

FAA-certificated mechanic. The repairman certificate is unique to the aircraft and its builder and 

does not transfer with the sale of the E-AB aircraft.

 14 Certain aircraft that are sport pilot eligible may be piloted by individuals holding a sport pilot certificate.

15 Title 14 CFR 65.104 defines the eligibility, privileges, and limitations of a repairman certificate—experimental 

aircraft builder. The original builder of an E-AB aircraft may apply for a repairman certificate, authorizing him or 

her to perform condition inspections in accordance with the operating limitations of the aircraft he or she 

constructed. The repairman certificate is specific to the individual and aircraft and does not transfer with the sale of 

an aircraft.
NTSB The Safety of Experimental Amateur-Built Aircraft

10

2. Accident Trends Across the Decade

NTSB aviation accident investigation records were used to compare the accident history 

of amateur-built aircraft with comparable non-E-AB aircraft from 2001 through 2010. An 

extensive review was conducted of these data to ensure that accident-involved aircraft were 

correctly identified as E-AB aircraft or non-E-AB aircraft.16 In particular, aircraft identified as 

having special light-sport, experimental light-sport,17 or other categories of experimental 

airworthiness certificates were removed from the amateur-built aircraft accident data.18

Because general aviation operations include a wide range of aircraft types, a subset of 

general aviation operations and aircraft was selected to provide comparisons to the E-AB aircraft

accident record and exposure data. The bulk of the E-AB aircraft fleet is comprised of 

single-engine, piston-powered airplanes, but it also includes other categories of aircraft such as 

helicopters, balloons, gliders, and gyroplanes.19 Therefore, the comparison group selected to 

most closely match E-AB aircraft includes all single-engine, piston-powered airplanes; 

piston-powered helicopters; balloons; and gliders that are not certificated as experimental 

amateur-built. This group included aircraft with both standard category and light-sport 

airworthiness certificates. Similarly, the activity and accident records associated with the 

comparison aircraft were limited to personal and business flights to most closely match the 

activity of E-AB aircraft20 that are built for personal education and recreation and are restricted 

from operating for compensation or hire.21 Throughout the remainder of this chapter, the two 

groups of aircraft will be referred to as the ―E-AB‖ and ―non-E-AB‖ aircraft groups.

 16 Previous analyses, such as Cook, Mark, 2010. Commentary: ―Homebuilt Aircraft Safety Picture Blurred by 

Bad Data,‖ Kitplanes, March, 2010, have criticized the accuracy in identifying amateur-built aircraft. NTSB staff 

worked with the FAA to validate the airworthiness certification of aircraft involved in general aviation accidents 

from 2001 through 2010, resulting in a net reduction of the number of E-AB accidents during the period.

17 Title 14 CFR 1.1 defines the design and performance characteristics of a group of simple, small, lightweight, 

low-performance aircraft; identified as light-sport aircraft. Title 14 CFR 21.190 also prescribes requirements for the 

issuance of a special airworthiness certificate for light-sport category aircraft. A detailed discussion of light-sport 

aircraft and associated aircraft and airworthiness certification is included in appendix H of this report.

18 A summary of the methodology and results of the data validation effort is included in Appendix A of this 

report.

19 The 2,134 accident aircraft from 2001 through 2010 validated as E-AB aircraft included 97 helicopters, 

75 gyroplanes, 16 gliders, and 4 balloons.

20 Although the non-E-AB group was limited to personal and business flights, the E-AB accident aircraft were 

reportedly engaged in a variety of activities other than personal flying, including business, flight instruction, and air 

show or air racing. In addition, there were 39 non-E-AB aircraft that were engaged in activities other than personal 

or business flying but are included in some analyses in this section because they were involved in ground or midair 

collision accidents with E-AB aircraft.

21 This approach likely underestimates active aircraft and flight activity and, therefore, overestimates accident 

rates associated with the comparison group of non-E-AB aircraft. However, this conservative approach was selected 

to avoid overestimating the increased risks associated with amateur-built aircraft. 
NTSB The Safety of Experimental Amateur-Built Aircraft

11

2.1 Aircraft Fleet and Activity

Exposure data obtained from the FAA‘s annual General Aviation and Part 135 Activity 

Survey were used to calculate accident rates per 100,000 flight hours, which provided 

normalized comparisons of E-AB and non-E-AB aircraft accident experiences.

Figure 6 shows the estimated active aircraft and Figure 7 shows the annual flight hours 

from 2001 through 2010 for E-AB and non-E-AB aircraft.

Figure 6. Number of active E-AB and non-E-AB aircraft annually from 2001 to 2010.

131.8 131.7

16.7

21.3

0

20

40

60

80

100

120

140

160

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Active Aircraft (thousands)

Calendar Year

Estimated Active E-AB and Non-E-AB Aircraft in the 

U.S., 2001–2010

Non-E-AB E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

12

Figure 7. FAA-reported number of hours flown for E-AB and non-E-AB aircraft annually from 

2001 through 2010.

2.2 Accidents as a Function of Aircraft Age

Previous comparisons of E-AB aircraft accident rates to other segments of general 

aviation22 have sought explanations for the substantially elevated accident rates, either as a 

proportion of the active aircraft fleet or of flight hours.23 One observation is that much higher 

proportions of E-AB aircraft accidents occur early in the operational life of the aircraft, 

particularly during the Phase I flight test as a condition of airworthiness certification. Figure 8

compares the cumulative distributions of accident aircraft from 2001 through 2010 at various 

points in the total airframe lifespan (in hours) for E-AB and non-E-AB aircraft. Direct 

comparison of the airframe hours at the time of the accident is difficult because of the likely 

differences in the operational history of the two groups of aircraft. However, the large difference 

in the number of E-AB aircraft accidents occurring very early in the operational life of the 

aircraft suggests underlying differences between the two fleets of aircraft. For example, 152 of 

 22 Wanttaja, Ron. Examining Homebuilt Aircraft Accidents, 2010.

23 See, for example FAA Advisory Circular 90-109, http://www.faa.gov/documentLibrary/media/Advisory_

Circular/90-109.pdf..

11.7

7.7

0.8

0.9

0

2

4

6

8

10

12

14

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Flight Hours (millions)

Calendar Year

Hours Flown by E-AB and Non-E-AB Aircraft, 

2001–2010

Non-E-AB E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

13

the 1,622 accident E-AB aircraft (9 percent) with airframe data had fewer than 10 airframe hours 

at the time of the accident, compared with only 18 of the 6,450 non-E-AB aircraft (.3 percent) 

with airframe data. This is despite a total fleet of, and number of accidents involving, non-E-AB 

aircraft being several times greater than that of E-AB aircraft.

Figure 8. Cumulative distribution of airframe hours of E-AB and non-E-AB aircraft involved in 

accidents from 2001 through 2010; 8,072 accident aircraft with available airframe hours 

information.

Although these differences in accumulated airframe hours might suggest differences in 

airworthiness between the two groups of aircraft, they may also be influenced by differences in 

the way the aircraft are operated and maintained and by the pilots who fly them. 

12 18 64

184

622

956

102 152

288

551

1,265

1,523

1,622

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

< 5 <10 <40 <100 <500 <1000 Total with

hour data

Accident Aircraft 

Airframe Hours

Cumulative Distribution of E-AB and Comparison 

Accident Aircraft Airframe Hours, 2001–2010

Non-E-AB E-AB

6,450
NTSB The Safety of Experimental Amateur-Built Aircraft

14

2.3 Comparison of Accident Characteristics

An analysis of the accident occurrences and associated phases of flight provides further 

insight. E-AB and non-E-AB aircraft accident characteristics were summarized using a coding 

structure developed by the Commercial Aviation Safety Team (CAST) and the International 

Civil Aviation Organization (ICAO) that are useful in describing the characteristic circumstances 

of aviation accidents.24 For ease of aggregate analysis and interpretation, the NTSB identifies 

one of the CAST-ICAO Common Taxonomy Team (CICTT) event codes as the defining event 

for each accident and that is the categorization used in this report to characterize accident 

circumstances. Each accident occurrence can also be associated with a CICTT phase code, 

identifying the phase of flight during which an accident occurred. 

Figure 9 compares E-AB and non-E-AB aircraft groups relative to the defining event for 

all accidents investigated between 2001 and 2010. Figure 10 compares the percentage of fatal 

accidents in each major event category for E-AB and non-E-AB aircraft during this period.

 24 The CAST/ICAO Common Taxonomy Team (CICTT), comprised of U.S. and international government and 

industry experts, has developed consensus coding of aircraft accident occurrences categories and associated phases 

of flight. CICTT occurrence and phase of flight definitions and usage notes can be found at the CICTT website: 

http://www.intlaviationstandards.org/.
NTSB The Safety of Experimental Amateur-Built Aircraft

15

Figure 9. Distribution of accidents involving E-AB and non-E-AB aircraft involving the 10 most 

common CAST/ICAO occurrence categories from 2001 through 2010.

1.4%

2.8%

4.9%

8.0%

4.8%

10.9%

17.0%

18.1%

13.7%

14.0%

0.8%

1.0%

1.6%

5.8%

9.4%

9.8%

10.5%

11.7%

23.1%

23.2%

0% 5% 10% 15% 20% 25%

Midair Collision

Runway Excursion

Weather Related

Runway Contact

System/Component (NonPowerplant)

Fuel Related

Loss of Control on Ground

Collision With Objects or

Terrain

Loss of Control in Flight

System/Component

(Powerplant)

Percentage of Accidents

CAST/ICAO Occurrence Category

Top 10 Accident Occurrence Categories for E-AB 

and Non-E-AB Aircraft, 2001–2010

E-AB Non-E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

16

Figure 10. Distribution of fatal accidents involving E-AB and non-E-AB aircraft involving the 10 

most common occurrence categories from 2001 through 2010.

Powerplant failures and loss of aircraft control in flight were the most common accident 

events for E-AB aircraft, while collisions with objects or terrain and loss of control on ground 

were the most common accident events for the non-E-AB aircraft. A noticeably larger proportion 

of E-AB aircraft accidents and fatal accidents involved system failures (either powerplant or 

non-powerplant). The difference in accident event types, and the typical impact forces involved 

with those events, identifies an important source of the historic difference in the fatal accident 

rates for E-AB aircraft.

0.3%

1.7%

1.0%

4.0%

16.0%

5.9%

3.6%

25.4%

8.5%

29.7%

0.9%

0.9%

1.8%

2.2%

3.3%

6.0%

8.9%

14.1%

15.2%

43.9%

0% 10% 20% 30% 40% 50%

Low Altitude Operation

Unknown

Loss of Control on Ground

Midair Collision

Weather Related

Fuel Related

System/Component (NonPowerplant)

Collision With Objects or Terrain

System/Component

(Powerplant)

Loss of Control in Flight

Percentage of Accidents

CAST/ICAO Occurrence Category

Top 10 Fatal Accident Occurrence Categories for 

E-AB and Non-E-AB Aircraft, 2001–2010

E-AB Non-E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

17

Loss of aircraft control in flight was the most common event in fatal accidents for both 

groups of aircraft, but E-AB aircraft experienced a noticeably greater proportion of loss of 

control in flight events than the non-E-AB aircraft group. There is also a noticeable difference 

between the fatal accident histories of the two groups related to weather, with weather-related 

accident events being much less common for E-AB aircraft. This likely reflects differences in 

aircraft usage associated with a smaller proportion of E-AB aircraft certified for flight in 

instrument meteorological conditions. 

2.4 Accident Pilot Demographics

Accident records were reviewed to gain a better understanding of the role of the pilot in 

the accident history. Pilots of E-AB aircraft involved in accidents between 2001 and 2010 were 

older (median age was 57 years) than the accident pilots of non-E-AB aircraft (median age was 

53 years).

25 Figure 11 shows the median age of accident pilots involving these two groups of 

aircraft each year from 2001 through 2010. Accident pilots of E-AB aircraft were consistently 

older than those of comparison aircraft and the difference increased slightly over the period.

 25 This difference was statistically significant (Mann-Whitney U = 6848562.0, N (non-E-AB aircraft) = 7,975, N

(E-AB aircraft = 2,104), p < 0.001).
NTSB The Safety of Experimental Amateur-Built Aircraft

18

Figure 11. Median accident pilot age for E-AB and non-E-AB aircraft, 2001–2010.

The E-AB aircraft accident pilots had more total flying time (median flight hours were

1,000 hours) than the non-E-AB aircraft pilots (median flight hours were 810 hours),

26 and a 

slightly higher proportion of E-AB aircraft pilots held commercial or airline transport pilot 

certificates. These results indicate that pilots of E-AB aircraft have similar, or higher, levels of 

total aviation experience than pilots of comparable aircraft engaged in similar general aviation 

operations. However, E-AB aircraft accident pilots had less than half (median flight hours were

 26 This difference was statistically significant (Mann-Whitney U = 7248897.5, N (non-E-AB aircraft) = 7,824, N

(E-AB aircraft = 2,024), p < 0.001).

53 53

56 57 58 57 57 58

60 61

50 52 51 52 52 52

54 54 54 55

10

20

30

40

50

60

70

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Median Age (years)

Calendar Year

Median Age of E-AB and Non-E-AB Aircraft 

Accident Pilots, 2001–2010

E-AB Non-E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

19

61 hours) of the time in the accident aircraft type than did the pilots of non-E-AB accident 

aircraft (median flight hours were 152 hours).

27

2.5 Limitations in the Analysis of Retrospective Data

The use of historical accident data alone is insufficient to provide a comprehensive 

analysis of E-AB aircraft safety issues. Several important matters cannot be resolved. For 

example, these data do not reliably identify whether the pilot of the accident-involved E-AB 

aircraft was the builder, the owner, or someone else. Nor do these accident data reliably identify 

whether the accident flight occurred during the flight test of the aircraft. The accident records 

also do not distinguish between owner/operator-built aircraft and E-AB aircraft that have been 

purchased used. Further, available data fail to provide a description and understanding of the 

broader population of E-AB aircraft and aviators who are not involved in accidents.

In an effort to overcome these data limitations, the NTSB analyzed two additional 

datasets for this study, a detailed case-series dataset of E-AB aircraft accidents investigated by 

the NTSB during 2011 and a survey of amateur aircraft builders and operators that was 

conducted by the EAA. These are the subject of the following chapters.

Additionally, staff visited manufacturers of E-AB aircraft kits, interviewed FAA officials 

and contractors, participated in discussions with the General Aviation Joint Steering Committee, 

and held numerous discussions with officials and members of the EAA, including its 

Homebuilders Aircraft Council. NTSB staff also reviewed industry and government training 

resources applicable to E-AB aircraft construction, certification, and oversight, such as the 

FAA‘s Initial Amateur-Built and Light-Sport DAR Seminar training course covering mandatory 

DAR training for amateur-built or light-sport certification,28 and the EAA‘s RV Assembly, 

SportAir workshop.29

 27 This difference was statistically significant (Mann-Whitney U = 3759648.5, N (non-E-AB aircraft) = 6,819, 

N (E-AB aircraft = 1,604), p < 0.001). Statistical test results are provided here to illustrate differences between the 

characteristics of the two groups of accident pilots. A similar pattern of E-AB aircraft pilot experience was observed 

in the 2011 accident data, but no similar comparisons were evaluated through statistical testing.

28 The purpose of this course is to ensure that DARs understand FAA expectations, regulations, policy, 

procedures, forms, records, and any issues unique to amateur-built and light-sport aircraft. FAA inspectors also 

attend this course.

29 This is one of a group of similarly organized workshops offered by the EAA on topics pertaining to the 

assembly and operation of amateur-built aircraft such as the Code of Federal Regulations regarding amateur-built 

aircraft, tools required during assembly, workshop requirements, insurance, engine and propeller selection, and 

flight testing. The RV assembly workshop curriculum included a classroom presentation followed by ―hands-on‖ 

sheet metal projects, including a small airfoil section patterned after a Van‘s Aircraft Company RV wing intended to 

include the majority of skills necessary to build the aircraft.
NTSB The Safety of Experimental Amateur-Built Aircraft

20

3. The Calendar Year 2011 Case-Series of E-AB 

Aircraft Accidents

In order to facilitate a fuller understanding of the circumstances of E-AB aircraft

accidents, beyond that possible from the historical record, the NTSB conducted detailed 

investigations of all 224 E-AB aircraft accidents involving 227 E-AB aircraft during calendar 

year 2011.30 These detailed investigations employed the supplementary data form shown in 

appendix A. This form was completed for each of these accidents to collect additional 

information on aircraft performance, builder and pilot characteristics, and other factors to 

augment the data routinely collected in NTSB accident investigations. In addition, FAA 

airworthiness certification files and FAA registration files were obtained for each of the accident 

aircraft for which such files were available.31

Fifty-four of the 224 accidents were fatal, claiming the lives of 67 of the 300 individuals 

carried aboard the accident aircraft.32 Figure 12 shows the locations of these accidents in the 

continental United States. The complete list of accidents is shown in appendix F.

 30 Three of the 224 accidents involved collisions between two E-AB aircraft, accounting for a total of 227 E-AB 

aircraft.

31 Two accidents involved unregistered aircraft for which such files were not available.

32 At the time of this report, 40 percent of the 227 accidents did not yet have published probable cause 

statements. 
NTSB The Safety of Experimental Amateur-Built Aircraft

21

Figure 12. Locations of the 224 E-AB aircraft accidents occurring in the United States during 

calendar year 2011.

An analysis of these accidents illustrates several important characteristics and features.

The most notable is that powerplant failure and loss of control in flight were the most common 

factors associated with E-AB aircraft accidents occurring in 2011, the same pattern seen among 

E-AB aircraft accidents occurring between 2001 and 2010. 

Additional review of the 2011 accident data provided detail about E-AB accident aircraft 

and pilots not available from review of the 2001–2010 accident records. Some of the more 

interesting findings are summarized below. It was found that: 

A larger proportion of E-AB aircraft accidents in 2011 involved used E-AB aircraft 

compared with accidents involving aircraft owned by the original builder.

A high proportion of these used E-AB aircraft accidents occurred shortly after being 

purchased. 

There were a greater number of accidents occurring during the first flight by the new 

owner of a used E-AB aircraft compared with the first flight of a newly built aircraft. 
NTSB The Safety of Experimental Amateur-Built Aircraft

22

Loss of control in flight was the most common occurrence for first flights of both 

newly built and newly purchased aircraft.

Other key findings associated with the detailed E-AB aircraft accidents occurring in 2011 

are provided below. 

3.1 Characteristics of the 224 E-AB Aircraft Accidents Occurring in 

2011

Figure 13 plots the CICTT33 codes for the 227 E-AB aircraft involved in 224 accidents 

during calendar year 2011. Powerplant failures were observed in 57 of the accident aircraft, 

including 8 fatal accidents—by far the leading type of occurrence. Most (53 of 57) of the 

powerplant failures involved airplanes, the remaining 4 accidents involved helicopters. 

Type-certificated aircraft engines failed in 40 percent of these accidents, 37 percent involved 

non-type-certificated aircraft engines, and 23 percent of the powerplant failures occurred in 

automotive conversion engines. Of the 49 engines for which the origin could be established, 

57 percent were new (including one that had been ―mothballed‖ for 60 years) and 33 percent

were overhauled or factory reconditioned. The remaining 10 percent were used engines that had 

not been overhauled.34 A wide variety of failures were observed in these powerplant-involved 

accidents. These include:

A bearing on a builder-designed secondary shaft of a Rotorway helicopter equipped 

with a new non-type-certificated aircraft engine froze, causing a fatal accident.

An improperly installed coolant hose fitting failed on an airplane powered by a new 

Subaru automotive conversion engine, causing engine overheating and loss of power.

Loose, or cross-threaded, spark plugs on a type-certificated Continental engine that 

had been overhauled by an FAA certified mechanic, and on a factory-reconditioned 

Rotax aircraft engine led to two accidents. 

The rupture of an oil supply line because of abrasion from an improperly positioned 

hose clamp led to the failure of a new Jabiru engine.

In many cases, the investigator was only able to determine that the engine had 

experienced total or partial loss of power for undetermined reasons.

Loss of control in flight was the next highest overall occurrence and accounted for the 

most fatal occurrences. Half of the loss of control accidents occurred on takeoff or initial climb.

In a number of these accidents, insufficient takeoff speed, early rotation, or too steep a climb on 

 33 International Civil Aviation Organization, Common Taxonomy Team, Aviation Occurrence Categories 

– Definitions and Usage Notes, October 2008.

34 Among the population of E-AB aircraft accidents in 2011, 50 percent of the aircraft used type-certificated 

aircraft engines, 34 percent used non-type-certificated aircraft engines, 15 percent used automotive conversion 

engines, and 1 percent were unpowered gliders. For the engines whose origin could be determined, 60 percent were 

new, 29 percent were overhauled, and 11 percent were used.
NTSB The Safety of Experimental Amateur-Built Aircraft

23

takeoff led to aerodynamic stalls and loss of control. In at least two cases, pilots admitted that 

their aircraft was at or over maximum gross weight, resulting in compromised climb 

performance, aerodynamic stall, and loss of control. Inadequate airspeed management on 

approach and landing also led to aerodynamic stall and loss of control in a number of other 

accidents. In one instance, a pilot was surprised on takeoff when the tail came up more quickly 

than he expected on the first flight of the tailwheel airplane that he had built, and he flew the 

aircraft into a nose-high stall and lost control. The 64-year-old student pilot had never flown a 

tailwheel airplane before and did not have a tailwheel endorsement.

The next most common accident occurrences were loss of control on the ground, 

abnormal runway contact, and failures of systems or components other than the powerplant. 

Three of these accidents were fatal. Controlled flight into terrain accounted for five fatal and five 

non-fatal accidents.
NTSB The Safety of Experimental Amateur-Built Aircraft

24

Figure 13. CAST/ICAO occurrence categories for E-AB accident aircraft, 2011.

Figure 14 summarizes the phase of flight of the 227 aircraft at the time of the accident 

occurrence in 2011. Landing was the phase of flight most often associated with E-AB aircraft

accidents, although only one of these accidents was fatal. As indicated previously, many of the 

0 20 40 60

System/Component Failure (Powerplant)

Loss of Control in Flight

Loss of Control on Ground

Abnormal Runway Contact

System/Component Failure (Non-Powerplant)

Fuel Related

Collision on Takeoff or Landing

Controlled Flight Into Terrain

Midair Collision

Ground Collision

Low Altitude Operation

Runway Excursion

Runway Incursion (Vehicle, Aircraft, Person)

Unknown

Undershoot/Overshoot

Windshear/Thunderstorm

Other

Abrubt Maneuver

Fire/Smoke (Non-Impact)

Runway Incursion (Wildlife)

Unintentional Flight into IMC

Accident Aircraft

CAST/ICAO Occurrence Category

CAST/ICAO Occurrence Categories for E-AB 

Accident Aircraft, 2011 

(Includes one Midair collision between two E-AB aircraft, and two Runway Incursion 

accidents between two E-AB aircraft)

Total Fatal
NTSB The Safety of Experimental Amateur-Built Aircraft

25

loss of control in flight accidents occurred during takeoff and initial climb or during approach 

and landing.

Figure 14. Phase of flight for the 227 aircraft involved in the 2011 E-AB aircraft accidents.

3.1.1 E-AB Aircraft Built by Owner Versus E-AB Aircraft Bought Used

More than one-half (125 of 227) of the aircraft involved in accidents during 2011 had 

been bought used rather than having been built by their current owner.35

Figure 15 compares CAST/ICAO occurrence categories for the accidents involving E-AB 

aircraft built by their owners compared with those purchased used. The two groups of accident 

aircraft appear similar with respect to the types of accidents in which they were involved.

 35 By comparison, 23.5 percent of survey respondents reported owning a used E-AB aircraft. The FAA‘s 

aircraft registry does not include the detail necessary to determine this breakdown for all E-AB aircraft.

1

31

42

36

27

19

60

3

4

0

5

13

12

12

8

1

0

4

0 10 20 30 40 50 60 70

Standing

Takeoff

Initial Climb

En Route

Maneuvering

Approach

Landing

Taxi

Unknown

Accident Aircraft

CAST/ICAO Phase of Flight

CAST/ICAO Phase of Flight for 

E-AB Accident Aircraft, 2011 

Total Fatal
NTSB The Safety of Experimental Amateur-Built Aircraft

26

Figure 15. CAST/ICAO occurrence categories for E-AB aircraft built by owner versus E-AB 

aircraft bought used, 2011.

Figure 16 shows the age of the accident aircraft (years since certification) for both the 

built-by-owner and bought-used aircraft. As might be expected, the accident E-AB aircraft that 

had been bought used, were older than those built by the owner at the time of the accident. The 

median years since certification was 14 for the accident aircraft purchased used, compared with 

3 years for those built by the owners. Figure 17 presents a slightly different picture. This figure 

plots the years that the accident aircraft has been owned by the two groups of owners. The two 

distributions are very similar and, in fact, the median time owned for the accident aircraft bought 

used was 2 years, compared with 3 years for the aircraft built by their owners.

0 5 10 15 20 25 30 35

System/Component Failure (Powerplant)

Loss of Control in Flight

Loss of Control on Ground

Abnormal Runway Contact

System/Component Failure (Non-Powerplant)

Fuel Related

Collision on Takeoff or Landing

Controlled Flight Into Terrain

Midair Collision

Ground Collision

Low Alltituide Operation

Runway Excursion

Runway Incursion (Vehicle, Aircraft, Person)

Unknown

Undershoot/Overshoot

Other

Windshear/Thunderstorm

Abrupt Maneuver

Fire/Smoke (Non-Impact)

Runway Incursion (Wildlife)

Unintended Flight Into IMC

Accident Aircraft

CAST/ICAO Occurrence Category

CAST/ICAO Occurrence Categories for E-AB 

Aircraft Built by Owner Versus E-AB Aircraft 

Bought Used, 2011

Built E-AB Bought Used E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

27

Figure 16. Years since certification for E-AB aircraft built by the owner versus those bought 

used.

19 18

10 8

11

20

16

2 1 1

7

4

31

79

0

10

20

30

40

50

60

70

80

90

<1 year 1–2 years 2–3 years 3–4 years 4–5 years 5–10 years >10 years

Accident Aircraft

Years Since Certification

Years Since Airworthiness Certification for 

Accident E-AB Aircraft Built by Owner Versus 

Those Bought Used

Built E-AB Bought Used E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

28

Figure 17. Years that the accident E-AB aircraft has been owned by the current owner.

3.2 Accident Pilot Demographics

The median age of accident pilots who had bought used E-AB aircraft was 62 years 

(ranging from 20–88), while for those who had built their aircraft the median age was 58 

(ranging from 16–83). Figure 18 shows the age distribution for these two groups of accident 

pilots.

19 18

10

8

11

20

16

23

32

17

10

12

24

7

0

5

10

15

20

25

30

35

<1 year 1–2 years 2–3 years 3–4 years 4–5 years 5–10 years >10 years

Accident Aircraft

Years Owned

Number of Years That the Accident E-AB was 

Owned by the Current Owner, 2011

Built E-AB Bought Used E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

29

Figure 18. Age distributions of accident pilots who had built their E-AB aircraft and those who 

had bought them used.

As shown in Figure 19, most accident pilots held private pilot or higher certificates, 

whether they had built their E-AB aircraft or bought it used. The two groups were also similar in 

total flight hours. The distribution of total flight hours are shown in Figure 20, and the total hours 

in the accident aircraft are shown in Figure 21. The bought-used group showed slightly more 

experience with a median of 1,550 total flight hours, compared with 1,248 hours for the pilots 

who had built their E-AB aircraft. Relative to experience in flying the accident E-AB aircraft, 

those who had built their E-AB aircraft had somewhat more time in the aircraft (median equals

100 hours) than those who had bought their aircraft used (median equals 70 hours).

2

33

57

9

52

58

0

10

20

30

40

50

60

70

<40 40–59 >59

Accident Pilots

Age

Age of Accident Pilots Who Built E-AB Aircraft 

and Those Who Bought Used E-AB Aircraft, 2011

Built E-AB Bought Used-EAB
NTSB The Safety of Experimental Amateur-Built Aircraft

30

Figure 19. Highest pilot certificate for accident pilots who bought used E-AB aircraft and those 

who built their E-AB aircraft.
NTSB The Safety of Experimental Amateur-Built Aircraft

31

Figure 20. Total flight hours for accident pilots who built their E-AB aircraft and those who 

bought used E-AB aircraft (based on data from 175 of 227 accident pilots).

0

3

6

9

15

19

8

4

2

14

1

7

6

13

15

10

8

9

6

20

0

5

10

15

20

25

Accident Pilots

Total Flight Hours

Total Flight Hours of Accident Pilots Who Built 

Their E-AB Aircraft and Those Who Bought Used 

E-AB Aircraft, 2011

Built E-AB Bought Used E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

32

Figure 21. Total E-AB aircraft flight hours for those who built their aircraft and those who bought 

used aircraft (based on data from 155 of 227 accident pilots).

3.3 E-AB Aircraft Characteristics Requiring FAA Certificate 

Endorsements

E-AB aircraft vary considerably with respect to structural and performance 

characteristics, some of which require specific training or a pilot logbook endorsement. 

Section 61.31(f) of 14 CFR stipulates that ground and flight training and an endorsement in the 

pilot‘s logbook are required to operate as the pilot-in-command of an airplane with an engine 

exceeding 200 horsepower. Section 61.31(i) of 14 CFR stipulates that pilots must receive 

training and a logbook endorsement to operate tailwheel airplanes. Finally, retractable landing 

gear is one of the characteristics of a complex airplane,36 requiring an endorsement under section 

61.31(e).

Table 1 shows the percentage of accident aircraft bought used and built by the owner 

with each of these design features that would have required specific training or a logbook 

endorsement. Unfortunately, data on whether these logbook endorsements were held were not 

available for most accident pilots.

 36 A ―complex‖ airplane is defined in 14 CFR 61.1(b)(3) as having retractable landing gear, flaps, and a 

controllable pitch propeller.

4

14

4

6

1

0

4

9

18

10

6

17

8

2 2

4

8

16 16

6

0

2

4

6

8

10

12

14

16

18

20

None 1–9 10–19 20–29 30–39 40–49 50–99 100–199 200–499 >499

Accident Pilots

Flight Hours in the E-AB Aircraft

Total Hours of Experience in the Accident Aircraft 

for Pilots Who Built Their E-AB and Those Who 

Bought the Aircraft Used

Built E-AB Bought Used E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

33

Table 1. Accident aircraft displaying design features that would require specific training or 

logbook endorsements.

Aircraft Feature Built by Owner Used E-AB Aircraft

Engine >200 HP 18% 11%

Tailwheel Equipped 40% 54%

Retractable Landing Gear 12% 11%

Total Accident Aircraft 102 125

Few accident aircraft met the ―high performance‖ definition of being powered by engines 

of more than 200 horsepower and even fewer would have required a complex aircraft 

endorsement by virtue of being equipped with a retractable landing gear. However, nearly half of 

the accident aircraft were equipped with tailwheel landing gear.

3.4 Characteristics of Builders and Their Aircraft

NTSB investigators were able to gather a limited amount of information on the building 

experiences and building choices of the 102 accident E-AB aircraft owners who had built their 

aircraft. Approximately 80 percent of the aircraft built by owners of accident aircraft were kitbuilt and 19 percent were plans-built. Only one accident involved an aircraft that was an original 

design. Most of the accident aircraft were built at the owner‘s home and/or in an airport hangar. 

A small number (less than 10 percent) were constructed at a kit manufacturer‘s factory or in a 

commercial aircraft service facility. Most were individual, rather than group, projects. About 

14 percent of builders received assistance from EAA Technical Counselors and about 9 percent

received assistance from aircraft kit manufacturers. About 12 percent reported receiving 

assistance from various friends, while 25 percent claimed to have received no assistance during 

their building project. Only 24 percent of these 102 builders reported having had their work 

inspected by EAA Technical Counselors, DARs, aircraft mechanics, or other experts during the 

building project.

Table 2 summarizes the principal characteristics of the accident E-AB aircraft built by the 

owners by the type of building project.
NTSB The Safety of Experimental Amateur-Built Aircraft

34

Table 2. Characteristics of accident E-AB aircraft built by owners.

Aircraft Characteristic Kit-Built Plans-Built Original Design

Engine Type

Type-Certificated Aircraft Engine 46% 48% 100%

Non-Type-Certificated Aircraft Engine 38% 26% 0%

Automotive Conversion 16% 26% 0%

Propeller Type

Fixed Pitch 43% 69% 0%

Ground Adjustable 24% 19% 0%

Constant Speed 33% 12% 100%

Avionics

Conventional 61% 87% 100%

Glass Cockpit 39% 13% 0%

Landing Gear Configuration

Tailwheel 39% 44% 100%

Tricycle 52% 56% 0%

Other 9% 0% 0%

Landing Gear Type

Fixed 90% 79% 100%

Retractable 10% 21% 0%

Number of Seats

One 5% 26% 100%

Two 83% 63% 0%

Three or More 12% 11% 0%

Total Accident Aircraft 82 19 1

The single accident involving an original design E-AB aircraft was a single seat, 

tailwheel airplane with a type-certificated aircraft engine, constant-speed propeller, and 

conventional avionics. Most kit-built and plans-built aircraft were two-seat, fixed tricycle gear 

aircraft with aircraft engines (type-certificated or non- certificated) and conventional avionics.

3.5 Airworthiness Certification and Transition Training

Of the 102 accident aircraft built by the owners, 2 were unregistered and 2 had 

incomplete certification records. Certification records of the remaining 98 accident aircraft 

showed that FAA inspectors had issued an airworthiness certificate for 43 aircraft and DARs had 

issued the certificate for the remaining 54 aircraft. In most cases (83 of 98), the Phase I flight test 

period prescribed for these aircraft was 40 hours within a restricted test area and constrained by 

an explicit set of operating limitations. For 14 of the 97 accident aircraft, a Phase I requirement 

of 25 hours was established, while 1 accident aircraft was assigned a 50 hour requirement.
NTSB The Safety of Experimental Amateur-Built Aircraft

35

Investigators determined the identity of the person performing the first test flight for 73 

of the 102 accident aircraft built by the owner. In most of these cases (84 percent), the builder 

was the test pilot.37 In the remaining cases for which information was available, the first test 

flight was performed by a more experienced pilot, frequently a friend of the builder.

Only 9 of the 102 accident aircraft builders reported having been subject to a requirement 

for transition training. In most cases, that requirement was imposed by their insurance company. 

Fifty-six of these builder/owners were issued repairman certificates that authorized them to 

perform required aircraft condition inspections, and an additional 12 owners held an FAA 

airframe and powerplant certificate, which also permitted them to perform both maintenance and 

inspections.

3.5.1 E-AB Aircraft Purchased Used

A total of 125 of the accident E-AB aircraft had been bought used. Most (119 of 125) 

were airplanes, 3 were gyroplanes, 2 were gliders, and 1 was a helicopter. Table 3 summarizes 

the important characteristics of the used accident E-AB aircraft, separated by kit-built, plans-built,

and original design.

 37 References to ―test pilot‖ throughout the report are intended to reflect the individual who performed the test 

flight and do not imply any specific level of qualifications.
NTSB The Safety of Experimental Amateur-Built Aircraft

36

Table 3. Characteristics of accident E-AB aircraft bought used.

Aircraft Characteristic Kit-Built Plans-Built Original Design

Engine Type

Type-Certificated Aircraft Engine 43% 72% 100%

Non-Type-Certificated Aircraft Engine 45% 8% 0%

Automotive Conversion 12% 15% 0%

Other/None 0% 5% 0%

Propeller Type

Fixed Pitch 51% 69% 100%

Ground Adjustable 22% 8% 0%

Constant Speed 27% 18% 0%

Avionics

Conventional 82% 86% 100%

Glass Cockpit 18% 14% 0%

Landing Gear Configuration

Tailwheel 48% 67% 100%

Tricycle 49% 26% 0%

Other 3% 7% 0%

Landing Gear Type

Fixed 86% 95% 100%

Retractable 14% 5% 0%

Number of Seats

One 6% 28% 0%

Two 89% 59% 100%

Three or More 5% 13% 0%

Total Accident Aircraft 84 39 2

Most of the accident E-AB aircraft that had been bought used were two-seat, kit-built 

airplanes with aircraft engines (either type-certificated or non-type-certificated) and conventional 

avionics. Roughly equal numbers of these airplanes were equipped with tricycle and tailwheel 

landing gear. The majority of the 39 plans-built aircraft purchased used were similarly equipped, 

including the only two E-AB gliders involved in accidents during 2011.

3.6 Accidents as a Function of Airframe Hours

Airframe hours were available for 67 of the 102 E-AB aircraft built by their owners and 

for 76 of the 125 E-AB aircraft that had been bought used. Figure 22 shows the cumulative 

percentages of each group of accident aircraft as a function of total airframe hours since 

manufacture. It is notable, but not unexpected, that substantially greater proportions of the 

built-by-owner aircraft were involved in accidents relatively soon after completion. Nearly 

50 percent of the built-by-owner aircraft had less than 50 airframe hours at the time of the 2011 
NTSB The Safety of Experimental Amateur-Built Aircraft

37

accident, compared with approximately 10 percent of the E-AB aircraft that had been bought 

used.38

Figure 22. Cumulative proportion of built-by-owner and bought used E-AB aircraft as a function 

of airframe hours.

3.7 Accidents During Phase I Flight Testing

Thirty-four of the calendar year 2011 accidents occurred during the Phase I flight test 

period required for the airworthiness certification of newly built E-AB aircraft. Thirty-one of 

these aircraft were built by their owner at the time of the accident, while two had been sold as 

used aircraft before completing the Phase I flight test period. Most (30 of 34) of these aircraft 

were airplanes and four were gyroplanes. Twenty-four were kit-built, 9 were plans-built, and 1 

was built from an original design. Eight of the Phase I accidents were fatal.

Figure 23 shows the CAST/ICAO occurrence category for these accidents, all of which 

involved a single aircraft.

 38 Insufficient data were available to compare the number of Phase I hours flown by the current owner for those 

aircraft that were bought used.

0

10

20

30

40

50

60

70

80

90

100

< 5 5 to 9 10 to 19 20 to 29 30 to 39 40 to 49 50 to 99 100 to 499 > 499

Cummulative Percentage of Accidents

Airframe Hours

Cummulative Proportion of Accident E-AB 

Aircraft Built by Owner and Bought Used at 

Increasing Airframe Hours, 2011

Built E-AB Bought Used E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

38

Figure 23. CAST/ICAO occurrence category for the 2011 E-AB accidents during Phase I of the 

flight test program.

All 11 of the Phase I aircraft that suffered powerplant failures were airplanes, comprising 

6 kit-built, 4 plans-built, and 1 original design. Four of the aircraft that suffered powerplant 

failures were equipped with type-certificated aircraft engines, two were equipped with 

non-type-certificated aircraft engines, and five were equipped with automotive conversion 

engines.

Ten of the 34 Phase I accidents involved loss of control in flight. Eight of these accidents 

involved airplanes and two accidents involved gyroplanes. Six of these aircraft were kit-built and 

four were built from published plans. 

A requirement for 40 Phase I flight test hours had been established for 33 of the builders, 

and one was assigned a 25-hour requirement when their airworthiness certificate was issued.

Figure 24 shows the total airframe hours accumulated at the time of the accident for each of the 

34 Phase I accident aircraft.

0 2 4 6 8 10 12

System/Component Failure (Powerplant)

Loss of Control in Flight

System/Component Failure (Non-powerplant)

Abnormal Runway Contact

Collision on Takeoff or Landing

Fuel Related

Loss of Control on Ground

Windshear or Thunderstorm

Other

Accident Aircraft

CAST/ICAO Occurrence Category

CAST/ICAO Occurrence Categories of E-AB 

Aircraft Accidents During Phase I Flight testing, 

2011

Total Fatal
NTSB The Safety of Experimental Amateur-Built Aircraft

39

Figure 24. Airframe hours at time of accident.

The E-AB aircraft builder was the accident pilot in 29 of the 34 accidents. Two of the 

accident aircraft were piloted by individuals who had bought the aircraft used during its Phase I 

test period, two were piloted by individuals recruited to perform the flight test, and one was 

piloted by the builder‘s spouse. The accident pilot was alone in the aircraft in 32 of the accidents, 

but a second individual was aboard the aircraft in 2 of the accidents, including 1 accident that 

was fatal to both individuals. It could not be determined whether the second individual was 

performing an explicit flight test function in either of those cases. The builder had performed the 

first test flight of the aircraft in 29 of the 34 E-AB aircraft accidents, including the 8 accidents 

that occurred on the first test flight.

3.8 Accidents During the First Flight for E-AB Aircraft Built by Owner

Ten of the 224 E-AB aircraft accidents during calendar year 2011 occurred during the 

first flight of the aircraft, including the 8 Phase I aircraft mentioned previously as well as the 

2 unregistered aircraft without airworthiness certificates. Seven of these aircraft were airplanes 

and three were gyroplanes. Seven were kit-built aircraft, and three were plans-built aircraft. Nine

0

10

20

30

40

50

60

70

80

90

100

<1 <3 <5 <7 <9 <11 <13 <15 <17 <19 <21 <23 <25 <27 <29 <31 <33 <35

Cummulative Percent of Aircraft

Airframe Hours

Cumulative Proportion of Phase I E-AB Accidents 

with Less Than 35 Airframe hours
NTSB The Safety of Experimental Amateur-Built Aircraft

40

of the ten test pilots were the aircraft builder, while the other test pilot was a certificated flight 

instructor who had been commissioned to perform the test flight. Five of the builders/test pilots 

held a private pilot certificate, three held a commercial pilot certificate (including the certificated

flight instructor performing the test flight), one held an air transport pilot certificate, and one 

held a student certificate. Table 4 summarizes the first flight accidents investigated during 

calendar year 2011.

Table 4. Characteristics of the 10 accidents in 2011 that occurred during the first test flight of 

the newly built E-AB aircraft.

NTSB Case 

#

Aircraft 

Category Aircraft Type Occurrence Category Phase Test Pilot

ERA11LA208 Airplane JTD Minimax Collision During 

Takeoff/Landing Takeoff Builder

ERA11LA213 Airplane Volksplane VP1

System/Component 

Malfunction or Failure 

(Powerplant)

Initial Climb Builder

CEN11CA336 Gyroplane KB3 Gyroplane Collision During 

Takeoff/Landing Takeoff Builder

CEN11FA346 Airplane Cassutt III Other Initial Climb Builder

CEN11LA432 Airplane Zenith CH-750 Loss of Control in Flight Take Off Builder

CEN11LA488 Airplane Volksplane VP1

System/Component 

Malfunction or Failure 

(Powerplant)

Initial Climb

Certified 

Flight 

Instructor

CEN11FA537 Airplane E-Racer Loss of Control in Flight Maneuvering Builder

ERA11LA459 Airplane Pegazair STOL 

100 Loss of Control in Flight Initial Climb Builder

CEN12LA013 Gyroplane Calidus Autogyro Loss of Control on Ground Landing Builder

CEN12CA029 Gyroplane

American 

Autogyro 

Sparrow Hawk

System/Component 

Malfunction or Failure –

(Non-Powerplant)

Takeoff Builder

3.9 Accidents During the First Flight for E-AB Aircraft Bought Used

Fourteen of the E-AB aircraft accidents in 2011 involved used aircraft being flown for the 

first time by their new owners. Five were fatal accidents, killing six occupants. All of these 

aircraft were airplanes, 11 kit-built and 3 plans-built. The accident pilot was the second owner of 

six of these airplanes, but two had had 2 previous owners, and five had had 3 or more previous 

owners. The new owner was the pilot-in-command in nine of these accidents, and was aboard the 
NTSB The Safety of Experimental Amateur-Built Aircraft

41

aircraft with a flight instructor in one case, and with a more experienced pilot in another. Two of 

the accidents involved the ferry flight of E-AB aircraft by commercial pilots, and one occurred 

during an evaluation flight conducted for the potential purchaser of a used E-AB aircraft by an 

air transport-rated pilot. Six of the nine owners piloting their aircraft held private pilot 

certificates, one held a commercial certificate, one held an air transport pilot certificate, and one 

new owner did not hold a pilot certificate.

Table 5 summarizes the accidents involving the first flight of E-AB aircraft bought used 

that were investigated during 2011.
NTSB The Safety of Experimental Amateur-Built Aircraft

42

Table 5. Accidents involving the first flight after purchase of E-AB aircraft bought used.

NTSB Case 

#

Aircraft 

Category Aircraft Type Occurrence Category Phase Pilot

CEN11CA326 Airplane Quickie Q2 System/Component 

Malfunction or Failure –

(Non-Powerplant)

Maneuvering Owner

ERA11LA336 Airplane Kitfox II Loss of Control in Flight Initial Climb Friend

CEN11FA434 Airplane Lancair 320 Loss of Control in Flight Approach Ferry Pilot

CEN11LA455 Airplane Rans S-17 Loss of Control in Flight Initial Climb Owner

ERA11CA432 Airplane Rans S-6S Abnormal Runway Contact Takeoff Owner

ERA11FA463 Airplane Quad City 

Ultralight 

Challenger II

Controlled Flight into Terrain Maneuvering Owner

CEN11FA597 Airplane Lancair 235 Loss of Control on Ground Takeoff Owner

CEN11FA616 Airplane Christen Eagle II System/Component 

Malfunction or Failure 

(Powerplant)

Initial Climb Owner

CEN11LA669 Airplane Vans RV-10 System/Component 

Malfunction or Failure 

(Powerplant)

En Route Owner

ERA12LA011 Airplane Rand Robinson 

KR-2

Loss of Control in Flight Initial Climb Owner

CEN12CA081 Airplane Davis DA-2A Loss of Control on Ground Landing Owner

ERA12CA096 Airplane Loehle P-5151 Windshear/Thunderstorm Approach Evaluation 

Pilot

CEN12LA102 Airplane Rans S-12 Loss of Control in Flight Approach Certified 

Flight 

Instructor

WPR11CA321 Airplane Thorp T-211 Fuel Related En Route Ferry Pilot
NTSB The Safety of Experimental Amateur-Built Aircraft

43

4. The EAA Survey of E-AB Aircraft Owners and 

Builders

Past evaluations of E-AB aircraft safety have been limited by the lack of background 

information about E-AB aircraft builders, pilots, and owners. In order to establish a better 

understanding of this population, the EAA conducted a voluntary, anonymous web-based survey 

of E-AB aircraft owners from July 15 through August 31, 2011. The EAA shared the resulting 

anonymous data with the NTSB to support this study. The survey, shown in appendix B, 

collected demographic and flying experience information from respondents as well as detailed 

information about their E-AB aircraft and their experiences building, testing, and flying them. 

The survey data were analyzed by the NTSB and the results are reported in this chapter. 

The EAA promoted the survey with e-mail invitations to its members and announcements 

in the EAA e-Hotline electronic newsletter. In addition, the NTSB mailed 22,000 postcards to 

E-AB aircraft owners listed on the FAA‘s aircraft registry, encouraging them to participate in the 

EAA survey. Other members of the E-AB aircraft community, including Van‘s Aircraft 

Company, publicized the EAA survey and encouraged participation. The EAA received more 

than 5,000 responses to the survey and a total of 4,923 responses were considered sufficiently 

complete to support data analysis.

Survey respondents indicated whether they had already built an E-AB aircraft, were 

currently building their E-AB aircraft, or had purchased a used E-AB aircraft. Figure 25 shows 

the distribution of respondents among these categories by the kind of E-AB aircraft they owned.
NTSB The Safety of Experimental Amateur-Built Aircraft

44

Figure 25. Method of E-AB aircraft ownership by type of aircraft.

Most (97 percent) of the aircraft described by respondents were airplanes, while the other 

3 percent included helicopters, gyroplanes, gliders, balloons, and powered parachutes. The 

majority (63 percent) of respondents had already built the airplane that they described in the 

survey, while 24 percent had bought a used E-AB aircraft, and 13 percent were currently 

building their E-AB aircraft.

Figure 26 shows the years since certification for the respondents who built their E-AB 

aircraft and for those that bought used E-AB aircraft. As might be expected, respondents 

reporting on E-AB aircraft that they had built described a somewhat newer set of aircraft than did 

those who reported on E-AB aircraft that they had bought used.

1,129

3,019

646

28 88 13

0

500

1,000

1,500

2,000

2,500

3,000

3,500

Bought Used E-AB Built My E-AB Currently Building E-AB

Respondents

Method of Ownership

Method of E-AB Aircraft Ownership by Type of 

Aircraft

Airplane All Other Aircraft
NTSB The Safety of Experimental Amateur-Built Aircraft

45

Figure 26. Years since certification for E-AB aircraft built by the respondent versus E-AB aircraft 

bought used by respondents (based on 4,082 survey responses).

4.1 Respondent Demographics

The median age of respondents who had bought used E-AB aircraft was 60 years, for 

those who had already built their E-AB aircraft it was 62 years, and for those currently building 

their E-AB aircraft it was 56 years. Figure 27 shows the age distribution for these groups of 

respondents. Nearly 36 percent of respondents who reported their occupation indicated that they 

were retired.

2%

10% 10% 9% 7% 8%

25%

19%

10%

0 1% 2% 3% 4% 3%

21%

34% 33%

0

5

10

15

20

25

30

35

40

<1 1 2 3 4 5 6–10 11–20 >20

Percentage of Respondents

Years Since Certification

Years Since Certification of E-AB Aircraft Bought 

Used Versus Built by Owner

Built My E-AB Bought Used E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

46

.

Figure 27. Respondent age by method of E-AB aircraft ownership.

Figure 28 shows the highest pilot certificate held by method of E-AB aircraft ownership 

for the respondents who provided that information. The majority of respondents held a private 

pilot certificate, and the type of certificate was relatively uniform across the three groups.

2%

36%

61%

6%

41%

53%

11%

49%

40%

0

10

20

30

40

50

60

70

<40 Years 40–59 Years >59 Years

Percentage of Respondents

Respondent Age

Respondent Ages by Method of E-AB Aircraft 

Ownership

Built My E-AB Bought Used E-AB Currently Building E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

47

Figure 28. Highest pilot certificate by method of E-AB aircraft ownership.

Figure 29 shows the distribution of total years of pilot experience for each of the method 

of ownership groups, while Figure 30 shows the total flight hours for each of the groups. Median 

years of pilot experience for respondents who built their E-AB aircraft was 33 years, for those 

who bought used E-AB aircraft it was 31 years, and for those currently building their E-AB 

aircraft it was 23 years. Median total flight hours were 1,311 for respondents who had built their 

E-AB aircraft, 1,350 hours for those who had bought used E-AB aircraft, and 550 hours for those 

currently building an E-AB aircraft. Hours of total E-AB aircraft flying experience for the groups 

are summarized in Figure 31. Here, there is a distinct difference between the ―built my E-AB‖ 

(median total flight hours was 279 hours) and ―bought used E-AB‖ (median total flight hours 

was 200 hours) groups on the one hand, and the ―currently building my E-AB‖ group (median 

total flight hours was 0 hours) on the other, suggesting that this was the first E-AB aircraft 

experience for most of those currently building such aircraft.

14%

25%

59%

2%

18%

23%

50%

10% 9%

20%

58%

11%

0

10

20

30

40

50

60

70

Airline Transport Pilot Commercial Pilot Private Pilot Lesser Certificate

Percentage of Respondents

Highest Pilot Certificate

Highest Pilot Certificate By Method of E-AB 

Aircraft Ownership

Built My E-AB Bought Used E-AB Currently Building E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

48

Figure 29. Years of pilot experience by method of E-AB aircraft ownership.

0

5

10

15

20

25

30

35

40

45

50

0 1 2 3 4 5–9 10–19 20–39 >40

Percentage of Respondents

Years of Pilot Experience

Years of Pilot Experience 

by Method of E-AB Aircraft Ownership

Built My E-AB Bought Used E-AB Currently Building E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

49

Figure 30. Total Flight Hours by E-AB aircraft method of ownership.

0

5

10

15

20

25

Percentage of Respondents

Total Flight Hours

Proportion of Respondents in Various Flight Hour 

Categories by Method of E-AB Ownership

Built My E-AB Bought Used E-AB Currently Building E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

50

Figure 31. Total E-AB aircraft flight hours by method of ownership.

4.2 E-AB Aircraft Makes

Broadly speaking, an E-AB aircraft project can be characterized as an original design, 

where the builder creates the design and plans for a unique aircraft, fabricates the various parts, 

and assembles them as a one-of-a-kind aircraft; a plans-built project, where the builder fabricates 

the aircraft parts from raw materials (referred to as ―miscellaneous parts‖ on FAA Form 8050-88)

and assembles them according to published plans; or a kit-built project, where the builder 

assembles the aircraft from a kit consisting of prefabricated parts. Figure 32 shows the number of 

respondents who reported each of these types of building projects by method of E-AB aircraft 

ownership.

0

10

20

30

40

50

60

70

None 1–9 10–19 20–29 30–49 50–99 100–199 200–299 300–499 >499

Percentage of Respondents

Total E-AB Flight Hours

Flight Hours in E-AB 

by Method of E-AB Ownership

Built My E-AB Bought Used E-AB Currently Building E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

51

Figure 32. Type Building Project by E-AB aircraft method of ownership.

Kit-built projects clearly dominate among respondents who have already built their 

aircraft, bought the aircraft used, or are currently building the aircraft, although a significant 

number of aircraft in each group are built from published plans. A much smaller number of 

respondents in each group described an original design.

Overall, respondents reported 171 different E-AB aircraft kits accounting for 

approximately 75 percent of the aircraft in the survey. Appendix E provides additional detail 

about the manufacturers and models of aircraft built by survey respondents and details of their 

building process. 

4.3 E-AB Aircraft Characteristics Requiring FAA Certificate 

Endorsements

Considering only the 4,794 airplanes described by survey respondents, table 6 shows the 

percentage of aircraft in each of the E-AB aircraft groups (bought used, already built, or 

currently being built) displaying the design features for which the FAA requires additional 

training or endorsements. This table also shows the percentage of owners within those subsets of 

E-AB aircraft who possess the respective FAA endorsements to their pilot certificate. Some of 

the owners of these aircraft would not be required to possess a particular endorsement if they had 

acquired appropriate experience prior to the date that each of these requirements was established.

2%

19%

79%

3%

31%

66%

5%

27%

68%

0

10

20

30

40

50

60

70

80

90

Original Design Plans-Built Kit-Built

Percentage of Respondents

Build Project Type

Type of E-AB Building Project 

by Method of E-AB Ownership

Built My E-AB Bought Used E-AB Currently Building My E-AB
NTSB The Safety of Experimental Amateur-Built Aircraft

52

Table 6. Aircraft design features and corresponding pilot certificate endorsements.

Reported Aircraft Design Features Used E-AB Built My E-AB

Building My 

E-AB

Engine >200HP 9% 13% 19%

Tailwheel Equipped 61% 48% 46%

Retractable gear 12% 13% 17%

Approved for aerobatics 51% 43% 39%

Reported Pilot Certificate Endorsements Used E-AB Built My E-AB

Building My 

E-AB

Owners with a high performance 

endorsement 92% 87% 59%

Owners with a tailwheel endorsement 91% 92% 69%

Owners with a complex endorsement 81% 72% 56%

Only 10 percent to 20 percent of respondents reported the engine horsepower of their 

aircraft to be above 200, but 92 percent of the respondents who had bought used E-AB aircraft

and 87 percent of the respondents who built their E-AB aircraft reported having high 

performance endorsements to their pilot certificates. Some respondents likely had logged time in 

high performance aircraft prior to August 4, 1997, and would not be required to possess this 

endorsement.

A substantial proportion of the aircraft described by survey respondents were tailwheel 

airplanes, and more than 90 percent of owners of these aircraft reported having a tailwheel 

endorsement. Respondents who had logged time in tailwheel airplanes prior to April 15, 1991,

would not be required to have this endorsement.

From 12 percent to 17 percent of the respondents‘ aircraft were equipped with retractable 

landing gear. Most respondents who built their E-AB aircraft (72 percent) or bought it used 

(81 percent), as well as 56 percent of those building their E-AB aircraft, had an endorsement for 

complex aircraft.

Finally, a large proportion of the aircraft were reported by their owners to be approved 

for aerobatic maneuvers. The FAA approval for this function is reflected in the airworthiness 

certificate issued for E-AB aircraft.

4.4 The E-AB Aircraft Building Process

The 3,107 respondents who had already completed building their E-AB aircraft (or 

sometimes several) and the 659 respondents who were currently building an E-AB aircraft 

provided important insights into the building process. These respondents also indicated that they 

were aware of the support available from the E-AB aircraft community and that they utilized 

these resources. 
NTSB The Safety of Experimental Amateur-Built Aircraft

53

Of the respondents who had built, or were currently building, their E-AB aircraft, 

77 percent had purchased a kit, 20 percent had built, or were building, from published plans, and 

3 percent had developed original designs. 

Of the kit builders, 45 percent reported that they used a kit to save money and 39 percent

reported that they used a kit to obtain aircraft performance advantages. Similar results were 

reported by the plans-built respondents, with 46 percent using published plans to save money and 

29 percent using published plans to obtain aircraft performance advantages. Among the 

104 respondents who had developed original designs, only 27 percent used an original design to 

save money and 25 percent used an original design to obtain aircraft performance advantages.

Among kit builders, 56 percent had received at least one demonstration flight before they 

bought their kit. About 35 percent of the demonstrations were provided by the kit manufacturer 

and 25 percent were provided by private individuals. About 32 percent of the respondents who 

built, or were building, their aircraft from plans had received a demonstration before they 

undertook their project, most from private individuals. Eleven percent of respondents creating 

their own designs had a pre-project demonstration from private individuals.

Figure 33 shows the choice of engine among the 3,567 powered aircraft built, or being 

built, by survey respondents. Most aircraft across all three types of construction were powered by 

either type-certificated or non-type-certificated versions of traditional aircraft engines. However, 

21 percent of the original design aircraft and 20 percent of the plans-built aircraft used converted 

automobile engines.
NTSB The Safety of Experimental Amateur-Built Aircraft

54

Figure 33. Engine choices among E-AB aircraft builders.

Table 7 summarizes the principal equipment characteristics of the 2,898 kit-built, 

753 plans-built, and 104 original design aircraft reported by survey respondents. The percentages 

reported in the table are based on the total responses to each survey item, and the number of 

responses varies slightly between variables as a function of missing responses to some questions. 

Most plans-built (80 percent) and original design (55 percent) aircraft were equipped with 

fixed-pitch propellers, while more kit-built aircraft were equipped with constant-speed propellers 

(44 percent) than fixed-pitch (37 percent) propellers. Most original design and plans-built aircraft 

utilized conventional flight instruments, but there is a roughly even split between conventional 

instruments (54 percent) and glass cockpit avionics (46 percent) in kit-built E-AB aircraft.
NTSB The Safety of Experimental Amateur-Built Aircraft

55

Table 7. Principal characteristics of the kit-built, plans-built and original design E-AB aircraft 

built or being built by survey respondents.

Aircraft Characteristic Kit Built Plans Built Original Design

Propeller

Fixed Pitch 37% 80% 55%

Ground Adjustable 18% 7% 19%

Constant Speed 44% 13% 26%

Avionics

Conventional 54% 84% 75%

Glass Cockpit 46% 16% 25%

Landing Gear Configuration

Tailwheel 42% 62% 67%

Tricycle 56% 36% 30%

Other 2% 2% 3%

Landing Gear Type

Fixed 89% 77% 82%

Retractable 11% 23% 18%

Number of seats

One 4% 25% 33%

Two 85% 62% 45%

Three or more 11% 12% 22%

A large proportion of plans-built (62 percent) and original design (67 percent) E-AB 

aircraft are equipped with tailwheel landing gear, while the majority (56 percent) of kit-built 

E-AB aircraft are equipped with tricycle gear. Few E-AB aircraft are equipped with retractable 

landing gear. Most respondents reported two-seat aircraft, with much smaller numbers of 

respondents reporting single-seat aircraft or aircraft with more than two seats.

Figure 34 shows where the E-AB aircraft were built, or are being built. Most aircraft, 

whether kit-built, plans-built or original designs, are genuine ―homebuilt‖ projects, with an 

airport hangar the next most frequent building location.
NTSB The Safety of Experimental Amateur-Built Aircraft

56

Figure 34. The location at which the E-AB aircraft was, or is being, built.

Builders have access to a variety of sources of building assistance as they complete their 

aircraft. Figure 35 shows the sources of assistance that were utilized by the three groups of 

builders. Help and advice from other builders was the most frequently sought source of 

assistance by all three categories of builders. Kit manufacturers provided support to purchasers 

of their kits and sometimes to builders of plans-built projects. EAA Technical Counselors 

provided assistance to significant numbers of builders in each category, and builders also sought 

the assistance of certified airframe and powerplant mechanics.

Building Facility Used During Build by Project Type

Kit-Built

(2,995 Respondents)

63.0%

(1,888) 33.3%

(998)

Manufacturer

Factory

2.8%

(83)

Airport Hangar

Builder’s Home 76.3%

(566)

Airport Hangar

Plans-Built

(742 Respondents)

75.5%

(71)

23.4%

(22)

Original Design

(94 Respondents)

Builder’s

Home

Commercial

Factory

0.9%

(26)

Commercial

Facility

0.4%

(3)

23.3%

(173)

Builder’s Home Airport Hangar

Commercial Facility

1.0%

(1)
NTSB The Safety of Experimental Amateur-Built Aircraft

57

Figure 35. Sources of builder assistance.

Inspections during the building process also are an important source of support to 

builders, and Figure 36 identifies categories of individuals who provided this service to the three 

categories of builders. EAA Technical Counselors were the most frequently used inspectors 

during the building process, followed by other E-AB aircraft builders. Significant numbers of 

respondents also reported inspections by aircraft mechanics and FAA inspectors.

Builder Assistance Provided During Build by Project Type

Kit-Built

(5,288 Respondents)

Other E-AB

Builder 29.7%

(1,572)

17.8%

(941)

Aircraft Mechanic (A&P)

EAA Technical

Counselor

25.0%

(1,321)

27.5%

(1,454)

Kit Manufacturer

Other E-AB

Builder

43.4%

(447)

23.3%

(240)

Aircraft Mechanic

(A&P)

EAA Technical

Counselor

26.1%

(269)

Kit Manufacturer

7.2%

(74)

Plans-Built

(1,030 Respondents)

Other E-AB

Builder

45.7%

(37)

28.4%

(23)

Aircraft Mechanic

(A&P)

EAA Technical

Counselor

24.7%

(20)

Kit Manufacturer

1.2%

(1)

Original Design

(81 Respondents)
NTSB The Safety of Experimental Amateur-Built Aircraft

58

Figure 36. Individuals performing inspections during the building process.

E-AB aircraft builders can be certified repairmen, who are then authorized to conduct 

required annual aircraft condition inspections. Most E-AB aircraft builders, including 86 percent

of kit builders, 78 percent of plans builders, and 77 percent of original designers, reported having 

such certification.39

4.5 Transition Training

Survey respondents who had completed their E-AB aircraft were asked about the training 

that they had completed that was specific to the transition to their new aircraft. Table 8 shows the 

proportion of each group of E-AB aircraft builders who had received transition training before 

their first flight in their new aircraft and the sources of that training.

 39 On the basis of 2,607 respondents reporting this information.

Inspecting Authority Performing Inspection During the Building

Process by Project Type

Kit-Built

(4,077 Respondents)

Other E-AB

Builder

28.0%

(1,142)

24.2%

(985)

Aircraft Mechanic (A&P)

EAA Technical

Counselor

32.2%

(1,314)

15.6%

(636)

FAA Inspector

27.2%

(270)

24.4%

(243)

25.3%

(251)

Plans-Built

(994 Respondents)

20.7%

(18)

31.0%

(27)

18.4%

(16)

Original Design

(87 Respondents)

23.1%

(230)

Other E-AB

Builder

Aircraft Mechanic (A&P)

EAA Technical

Counselor

FAA Inspector

29.9%

(26)

Other E-AB

Builder

Aircraft Mechanic (A&P)

EAA Technical

Counselor

FAA Inspector
NTSB The Safety of Experimental Amateur-Built Aircraft

59

Table 8. Source of transition training reported by respondents who had completed their E-AB 

aircraft.

Source of Transition Training Kit-Built Plans-Built Original Design

Had training prior to first flight 64% 37% 24%

Kit manufacturer 13% 0% 0%

Owner of same aircraft 21% 13% 0%

Owner of similar aircraft 10% 7% 9%

Owner of different aircraft 10% 2% 0%

Certificated flight instructor 26% 14% 10%

Total number of respondents 2452 578 70

The majority (64 percent) of kit–builders reported some type of transition training prior 

to their first flight, but this training came from a variety of sources. Only 37 percent of the 

plans-built and 24 percent of the original design groups reported specific transition training 

before their first flight. Insurance policies required such transition training for 37 percent of kit 

builders, 15 percent of the plans builders, and only 3 percent of the original designers. Many 

respondents (15 percent kit, 27 percent plans, and 37 percent original design) were self-insured, 

so this requirement did not apply.

4.6 Flight Test and Certification

Figure 37 shows the percentage of respondents who applied for airworthiness 

certification of their E-AB aircraft to ASIs or DARs to initiate the flight test requirement.
NTSB The Safety of Experimental Amateur-Built Aircraft

60

Figure 37. Issuer of airworthiness certificates reported by 2,597 of the 3,103 respondents who 

had completed their E-AB aircraft.

A somewhat higher proportion of kit builders sought airworthiness certification from 

DARs than from FAA airworthiness inspectors, while the opposite was true of plans-builders and 

original designers. 

Of the 2,475 respondents reporting their Phase I flight test requirement, 68 percent of 

builders were assigned to a 40-hour Phase I flight test period by the FAA and 22 percent were 

required to complete 25 hours of Phase I flight test. Only a few respondents reported less than 

25- or more than 40-hour requirements.40

Most builders reported having either ―very detailed‖ or ―somewhat detailed‖ flight test 

plans, but the survey did not ask for specifics of the test plans.

 40 FAA guidance suggests that a 10-hour test period is sufficient for certain aircraft such as balloons and 

gliders.

59.7%

34.5% 33.3%

39.8%

64.9% 66.7%

0.4% 0.6% 0.0%

0

10

20

30

40

50

60

70

Kit-Built Plans-Built Original Design

Percentage of Respondents

Project Type

Source of Airworthiness Certification 

by E-AB Aircraft Build Project Type

(2,549 Respondents)

DAR FAA Not yet issued
NTSB The Safety of Experimental Amateur-Built Aircraft

61

Figure 38 shows the sources of support used by these 3,103 builders in developing their 

Phase I test plans. The various sources of support are not mutually exclusive, and it is likely that 

reference to FAA AC 90-89A was a part of many of these test plans.

Figure 38. Sources of assistance in developing Phase I test plans for the 3,103 respondents 

who had built their E-AB aircraft. 

Finally, 79 percent of respondents who had completed building their E-AB aircraft

reported performing the first test flight themselves, while 12 percent had hired a test pilot, and 

9 percent had asked a friend or more experienced pilot to perform the test flight.

4.7 Owners of E-AB Aircraft Bought Used

A total of 1,151 survey respondents reported owning an E-AB aircraft that they had 

purchased used. Most (98 percent) were airplanes. Kit-built aircraft accounted for 762 

25%

22%

6%

49%

22%

5%

14%

39%

16%

3%

41%

6%

3%

13%

53%

16%

3%

27%

1%

6% 7%

0%

10%

20%

30%

40%

50%

60%

Percentage of Respondents

Assistance Source

Sources of Assistance in Developing Phase I Flight 

Test Plan by E-AB Aircraft Build Project Type 

(3,103 Respondents)

Kit-Built Plans-Built Original Design
NTSB The Safety of Experimental Amateur-Built Aircraft

62

(66 percent) of these aircraft, while 357 (31 percent) were plans-built, and 32 (3 percent) were 

original designs. Table 9 summarizes the characteristics of these aircraft.

Table 9. Characteristics of the E-AB aircraft bought used by survey respondents.

Aircraft Characteristic Kit-Built Plans-Built Original Design

Propeller

Fixed Pitch 42% 81% 62%

Ground Adjustable 21% 5% 14%

Constant Speed 37% 14% 24%

Avionics

Conventional 77% 96% 96%

Glass Cockpit 23% 4% 4%

Landing Gear Configuration

Tailwheel 51% 81% 55%

Tricycle 47% 19% 41%

Other 2% <1% 4%

Landing GearType

Fixed 87% 90% 86%

Retractable 13% 10% 14%

Number of seats

One 7% 34% 41%

Two 87% 64% 55%

Three or more 6% 2% 4%

About 60 percent of respondents reported having received at least one demonstration 

flight before they purchased their used E-AB aircraft. Very few reported that cost (4 percent) or 

performance (2 percent) were their primary motivations for buying their E-AB aircraft. Figure 39

shows the total hours of flying that these respondents had logged.
NTSB The Safety of Experimental Amateur-Built Aircraft

63

Figure 39. Total hours of flight experience for respondents who purchased used E-AB aircraft 

(1,132 of 1,151 reporting this information).

0

20

40

60

80

100

120

140

160

180

Respondents

Flight Hours

Total Flight Hours for Respondents Who 

Purchased Used E-AB Aircraft by Orginial Build 

Project Type (1,132 Respondents)

Kit-Built Plans-Built Original Design
NTSB The Safety of Experimental Amateur-Built Aircraft

64

5. Analysis and Discussion

Comparisons of accident occurrences and aircraft characteristics indicate that the E-AB 

aircraft accident record during 2011 was similar to that of the preceding ten-year period. 

Comparisons of accident records and the EAA‘s survey results indicate that the population of 

E-AB aircraft and of E-AB aircraft owners involved in accidents is similar, in most respects, to 

the larger population of E-AB aircraft and E-AB aircraft owners included in the survey. The 

average E-AB aircraft owners are older, relatively high-time pilots with private pilot or higher 

certification compared with other general aviation pilots. The E-AB aircraft fleet, as identified by 

accident and survey information, is increasingly dominated by kit-built airplanes. 

5.1 Key Findings

The pattern of study results identifies several safety-critical issues that, if addressed, 

could improve the E-AB aircraft accident record and better prepare pilots to operate E-AB 

aircraft. Study results indicate:

The largest proportion of E-AB aircraft accidents involved loss of control in flight 

and powerplant failures, and loss of control in flight has been the greatest contributor 

to fatal E-AB aircraft accidents. 

More than one-half of the E-AB aircraft accidents investigated in 2011 were aircraft 

that had been purchased used, rather than built by the current owner.

A large proportion of accidents occurs early in the operating life of a new E-AB 

aircraft, or shortly after being purchased by a new owner. 

During 2011, more E-AB aircraft accidents occurred during the first flight by a new 

owner of a used E-AB aircraft than during the first flight of a newly-built aircraft. 

The most common accident occurrence for first flights of both newly-built and newly 

purchased aircraft was loss of control in flight.

As a group, the E-AB accident aircraft did not experience a large number of structural 

failures or problems related to the strength of a particular aircraft‘s structure. Rather, the 

occurrences of aircraft system and component malfunctions and failures were most often 

associated with non-structural systems and components and were typically unique to the accident 

aircraft. However, the prevalence of accidents involving loss of engine power represents a 

fleet-wide safety concern for E-AB aircraft. Powerplant malfunctions and failures early in the 

operational life of a new aircraft include installation or system integrity issues that could be 

reduced by additional functional testing prior to flight. Powerplant accidents could be further 

reduced by using recorded data, when available, to monitor the condition and performance of the 

aircraft engine. 

Loss of control accidents may result from the unique aircraft controllability and design 

characteristics of a particular E-AB aircraft and because pilots may be inadequately prepared to 
NTSB The Safety of Experimental Amateur-Built Aircraft

65

manage these unique flight characteristics. Accidents may also occur during flight testing if 

pilots are not prepared for the unique demands of flight testing, or do not follow safe flight test 

procedures.

The safety of flight testing could also be improved by pilots developing and following a 

detailed flight test plan tailored to the aircraft and using all available information to evaluate and 

document the aircraft‘s performance during the flight test. Accidents involving subsequent 

owners of E-AB aircraft could be improved by ensuring that they are provided with the 

information necessary to safely operate their aircraft. The prevalence of loss of control in flight 

could be reduced by ensuring that all pilots are adequately trained prior to engaging in flight test 

operations or transitioning to an unfamiliar E-AB aircraft. The finding that E-AB aircraft

accident pilots had significantly more total experience but significantly less experience in the 

accident aircraft type provides further support for the potential safety benefits of transition 

training.

Finally, the study identified deficiencies in aircraft registration information and accident 

records pertaining to E-AB aircraft. Future efforts to assess E-AB aircraft safety and to act on 

identified safety concerns could be greatly improved by addressing these record-keeping 

deficiencies.

5.2 Opportunities to Improve Safety During Initial Certification

The pattern of results in this study identified areas for safety improvement that could be 

addressed during initial airworthiness certification. These include additional functional testing of 

aircraft systems to reduce instances of loss of engine power early in the operational life of a new 

aircraft, and submission of a detailed flight test plan to systematically assess aircraft 

airworthiness and flight characteristics, and development of a detail aircraft flight manual. 

5.2.1 Airworthiness Certification of E-AB Aircraft 

The United States imposes far less regulatory and safety oversight of E-AB aircraft than 

other countries,41 particularly prior to issuing an airworthiness certificate. Canadian regulations 

require the filing of a letter of intent before the project is started, a pre-covering inspection 

during the building process that ensures that methods of fabrication and workmanship adhere to 

aviation quality standards, and a final inspection.42 As part of the final inspection, the Canadian 

builder is required to report the results of a functional test of the aircraft‘s fuel system to ensure 

that adequate fuel is supplied to the engine in all flight attitudes and to test the integrity of the 

 41 How Other Countries Address Sophisticated and High-Performance Amateur-Built Aircraft, FAA 

Memorandum, May 12, 2011.

42 Part V – Airworthiness Manual Chapter 549 – Amateur-Built Aircraft, Canadian Aviation Regulations 

2010-1, Revised February 17, 1998.
NTSB The Safety of Experimental Amateur-Built Aircraft

66

fuel supply to the powerplant. The requirement for pre-cover inspections43 was removed from 

U.S. regulations in 1990.

44

In the United States, oversight of an E-AB aircraft effectively begins with the submission 

of the FAA Form 8130-6, Application for Airworthiness Certificate (Amateur-Built) when the 

project is completed.45 FAA AC 20-27G provides broad guidance relative to building E-AB

aircraft and the application for, and issuance of, an airworthiness certificate permitting the 

operation of an amateur-built aircraft. An airworthiness certificate for operating amateur-built 

aircraft may be issued either by an ASI or a DAR upon review of FAA Form 8130-6 (along with 

a certification that the major portion rule was met and a validation of aircraft registration), 

review of builder documents, and completion of an airworthiness inspection. Although much of 

the guidance for documentation review provided in Order 8130.2G is focused on establishing 

compliance with the major portion requirement, FAA Order 8130.2G, section 4102.d identifies 

FAA responsibilities at the time of certification to include: (1) ensuring that the aircraft is 

complete and all documentation is sufficient, (2) examining evidence that appropriate weight and 

balance measurements have been made to establish most forward and aft center of gravity 

locations under empty and maximum gross weight conditions; and (3) ensuring that the 

completed weight and balance report is available in the aircraft along with other applicable 

placards and markings. Section 4102.g stipulates that the ASI‘s or DAR‘s inspection, at a 

minimum, will determine that:

The ID plate meets the requirements of 14 CFR 45.11, as applicable.

The information on the ID plate matches the information on FAA Form 8130-6 and 

Aeronautical Center Form 8050-3.

The aircraft nationality and registration marks are in accordance with 14 CFR Part 45, 

subpart C.

The flight control system, engine(s), propeller(s), pitot static system, and associated 

instruments operate properly.

The cockpit instruments are appropriately marked and needed placards are installed 

and placed for easy reference.

System controls are appropriately placed, clearly marked, provide for easy access and 

operation, and function as intended by the amateur builder/owner.

 43 A ―pre-cover inspection‖ is an inspection conducted before the structural framework of the aircraft is 

―covered‖ with skin or other components.

44 FAA, Amateur-Built Aircraft Aviation Rulemaking Committee Final Report, February 14, 2008.

45 See discussion of E-AB airworthiness certification in chapter 1.
NTSB The Safety of Experimental Amateur-Built Aircraft

67

An emergency locator transmitter is installed, if required.46

All explosive devices used in ballistic parachutes are clearly marked and identified.

5.2.2 Functional Test Requirements

Among the list of items identified in FAA Order 8130.2G to be determined during 

inspection for initial airworthiness certification are requirements that the flight controls, engine, 

and propeller operate properly and that applicants are required to submit a weight and balance 

report. However, no specific functional testing is currently required. Analyses of E-AB aircraft 

accidents from 2001 through 2011 identify powerplant malfunctions and failures as the most 

common E-AB aircraft accident occurrence and second most common fatal accident occurrence 

overall, and the most common accident occurrence during Phase I flight testing. Results of the 

EAA survey of E-AB aircraft owners and builders and the accident record also highlight the 

wide variety of powerplants installed in E-AB aircraft, making powerplant-specific safety 

improvement efforts more difficult.

Investigations of many of the E-AB aircraft accidents during 2011 included in this report 

are still ongoing at the time of writing. However, there are examples among the completed cases 

that illustrate the potential safety benefit of requiring builders to conduct, and report the results 

of, a functional test of the aircraft‘s fuel system prior to certification.

On April 27, 2011, in Minford, Ohio, an experimental amateur-built Chang RV-10 

airplane was substantially damaged during an emergency landing following an in-flight fire. The 

aircraft was in the Phase 1 flight test phase and had accumulated about 4 hours flight time when 

the accident occurred. The pilot reported that he had noticed low fuel pressure during the 

accident flight and activated the fuel boost pump, after which the fuel pressure returned to within 

normal limits. As the airplane approached the intended destination airport, the pilot smelled 

smoke and observed a fire in front of his right foot. He discharged a fire extinguisher, which put 

out the fire; however, the cabin filled with smoke. He closed the fuel valve and opened the 

pilot‘s side door. The door separated and some of the smoke dissipated. The pilot made an 

emergency landing in a pasture, during which the fuselage and right wing were damaged.

A postaccident examination of the engine revealed a loose fuel line fitting at the 

mechanical fuel pump. The fire occurred along the lower fuselage skin in the center console area, 

which ran forward to aft between the pilot and copilot seats. The lower fuselage skin was burned 

through as a result of the in-flight fire. The NTSB determined the probable cause of this accident 

to be a loose fuel line fitting, which caused a fuel leak and subsequent in-flight fire.47

The 2001–2010 accident cases include additional examples involving loss of engine 

power during the first few hours of operation of a newly built aircraft. Some of the fuel system 

 46 Title 14 CFR 91.207(f) includes several exemptions to the requirements for U.S.-registered civil airplanes to 

be equipped with an emergency locator transmitter. Examples include single-person aircraft, aircraft engaged in 

flight instruction within a 50 nautical mile radius of the originating airport, or aircraft engaged in flight operations 

incident to design and testing.

47 NTSB accident case number CEN11CA321.
NTSB The Safety of Experimental Amateur-Built Aircraft

68

design and installation problems found in these cases include incorrectly installed fuel lines,48

crimped vent lines,49 system leaks,50 and a fuel system that did not provide adequate fuel 

pressure to maintain engine power.51

The NTSB concludes that a functional test of the aircraft fuel system could identify 

design deficiencies, leaks, and malfunctions prior to flight that would prevent fuel system- and 

powerplant-related accidents early in the operational life of an aircraft. For example, Canadian 

regulations and guidance for E-AB aircraft certification stipulate that a fuel flow test must be 

conducted, and a form reporting on the methods and result of this test be submitted during final 

airworthiness inspection.52 The prevalence of E-AB aircraft powerplant malfunctions and 

failures would be reduced with the implementation of a similar functional test as part of the 

airworthiness certification process. Therefore, the NTSB recommends that the FAA revise 

14 Code of Federal Regulations 21.193, FAA Order 8130.2G, and related guidance or 

regulations, as necessary, to define aircraft fuel system functional test procedures and require 

applicants for an airworthiness certificate for a powered experimental, operating amateur-built 

aircraft to conduct that test and submit a report of the results for FAA acceptance.

5.2.3 Flight Test Plan

FAA AC 90-89A provides extensive guidance to the E-AB aircraft builder for the 

development and execution of the flight test program, and it begins by stating the primary 

objectives of the flight test program:

a. The most important task for an amateur-builder is to develop a comprehensive 

FLIGHT TEST PLAN. This PLAN should be individually tailored to define the 

aircraft‘s specific level of performance. It is therefore important that the entire flight 

test plan be developed and completed BEFORE the aircraft‘s first flight.

b. The objective of a FLIGHT TEST PLAN is to determine the aircraft‘s controllability 

through-out all the maneuvers and to detect any hazardous operating characteristics or 

design features. This data should be used in developing a FLIGHT MANUAL that 

specifies the aircraft‘s performance and defines its operating envelope.53

EAA survey respondents who had achieved airworthiness certification were asked how 

detailed their flight plans were—37 percent claimed to have a ―very detailed‖ plan, while an 

additional 47 percent claimed a ―somewhat detailed‖ plan, and 16 percent indicated a ―somewhat 

informal‖ test plan. No consistent evidence of the existence or quality of flight test plans was 

available in accident investigation records or FAA certification files for the E-AB aircraft

involved in accidents during 2011.

 48 For example, see NTSB accident case number LAX04LA132.

49 For example, see NTSB accident case number CEN09CA382. 

50 For example, see NTSB accident case number LAX02LA256.

51 For example, see NTSB accident case number LAX07LA220.

52 Refer to Appendix G for a copy of the Canadian fuel flow test report form.

53 FAA AC 90-89A, Amateur-Built Aircraft and Ultralight Flight Testing Handbook, May 24, 1995.
NTSB The Safety of Experimental Amateur-Built Aircraft

69

FAA Order 8130.2G does not require that a builder‘s flight test plan be reviewed by the 

ASI or DAR. In marked contrast, the United Kingdom‘s CAP 65954 lists the following actions 

(among others) that the builder must satisfy before being issued a Permit to Fly for Test:

55

Have produced and have agreed by the CAA‘s Design and Production Standards 

Division Test Pilot your proposed flight test programme,

Have agreed with the CAA‘s Test Pilot the competency and suitability of the 

person(s) who will be undertaking the test flying,

Have agreed with the CAA‘s Test Pilot and the Regional Office Surveyor the 

arrangements for the management of your flight test program, and

Have produced a preliminary flight manual for the aircraft.

Absent a review and assessment of the flight test program by the FAA, the adequacy of 

the flight test program stipulated in Order 8130.2G cannot be ascertained or ensured. Therefore,

the NTSB recommends that the FAA revise 14 Code of Federal Regulations 21.193, FAA 

Order 8130.2G, and related guidance or regulations, as necessary, to require applicants for an 

airworthiness certificate for experimental, operating amateur-built aircraft to submit for FAA 

acceptance a flight test plan that will (1) ensure the aircraft has been adequately tested and has 

been determined to be safe to fly within the aircraft‘s flight envelope and (2) produce flight test 

data to develop an accurate and complete aircraft flight manual, and to establish emergency 

procedures and make a copy of this flight test plan should be made a part of the aircraft‘s 

certification file.

5.3 Opportunities to Improve Safety During Phase I Flight Test

The high proportion of E-AB aircraft accidents occurring early in the operational life of 

the aircraft, particularly during the first flight, provides evidence for the potential for safety 

improvements during Phase I flight testing. An area identified for improvement includes making 

sure that pilots are adequately prepared and capable of conducting flight test operations. The data 

collected during flight testing and the documentation of flight test results also provides

safety-critical information to subsequent aircraft owners and pilots. Additional safety benefits 

can be had for E-AB aircraft builders and subsequent owners by ensuring that a detailed flight 

test plan is completed and an aircraft flight manual is created during Phase I testing.

5.3.1 Phase I Flight Testing of E-AB Aircraft

Based on the review of the required forms and documents and the inspection of the 

aircraft, the ASI or DAR will issue a Special Airworthiness Certificate (FAA Form 8130-7) for 

the Category/Designation – Experimental, and the Purpose – Operating Amateur-Built Aircraft, 

 54 CAP 659 Amateur Built Aircraft: A Guide to Approval, Construction and Operation of Amateur Built 

Aircraft, UK Civil Aviation Authority, Aircraft Certification Department, Safety Regulation Group, November 

2005.

55 Comparable to the U.S. Phase I authorization granted with the E-AB Airworthiness Certificate.
NTSB The Safety of Experimental Amateur-Built Aircraft

70

ordinarily with an ―unlimited‖ expiration.56 The ASI or DAR will also issue a set of operating 

limitations for both a Phase I flight test period and Phase II operations, when the flight test 

period has been completed and recorded in the aircraft logbook.

Airworthiness records were reviewed for 223 of the 227 E-AB aircraft involved in 

accidents during 2011. Most of these files contained copies of Forms 8130-6 and 8130-7, 

documentation of the major portion requirement, and Phase I and Phase II operating limitations. 

Relatively few records contained documentation of weight and balance calculations and other 

details of the aircraft‘s construction that had supported the issuance of the airworthiness 

certificate.

57

The operating limitations issued with the Special Airworthiness Certificate for Operating 

Amateur-Built Aircraft include three main restrictions during Phase I: (1) All flights must be 

limited to a specifically defined geographic area over open water or sparsely populated areas 

having light air traffic, (2) the aircraft must be limited to the specified geographic area for an 

assigned number of hours, and (3) ―no person may be carried in the aircraft during flight unless 

that person is essential to the purpose of flight.‖ Under current regulations, Phase I is completed 

when the builder/owner has self-certified his or her compliance by recording the following, or a 

similarly worded statement, in the aircraft logbook or records [bolded text appears in the 

original]:

I certify that the prescribed flight test hours have been completed and the 

aircraft is controllable throughout its normal range of speeds and throughout

all maneuvers to be executed, has no hazardous operating characteristics or 

design features, and is safe for operation. The following aircraft operating 

data has been demonstrated during the flight testing: speeds VSO ____, VX

_____, and VY_____, and the weight _____ and CG location _____ at which 

they were obtained.

When this logbook endorsement is accomplished, the aircraft enters Phase II for an 

unlimited duration, the restriction on carrying passengers is removed, and the specific geographic 

restrictions of Phase I are replaced with the following:

This aircraft is prohibited from operating in congested airways or over densely populated 

areas unless directed by air traffic control, or unless sufficient altitude is maintained to effect a 

safe emergency landing in the event of a power unit failure, without hazard to persons or 

property on the ground.

FAA Order 8130.2G states that the period of assignment to the Phase I test period should 

be a minimum of 25 hours for E-AB aircraft with type-certificated engine/propeller combinations 

and that a minimum of 40 hours is required for any non-type-certificated engine/propeller 

combination or for any type-certificated engine/propeller combination that has been modified in 

any way. The recommended Phase I flight testing period for gliders, balloons, and ultralight 

 56 Expiry limits of E-AB airworthiness certificates changed, in most cases, to unlimited duration in 1979.

57 Current FAA airworthiness records associated with E-AB aircraft do not normally include information such 

as flight test plans, an aircraft flight manual, or a Pilot‘s Operating Handbook.
NTSB The Safety of Experimental Amateur-Built Aircraft

71

vehicles is ten hours. The order also states that any major change to an E-AB aircraft requires the 

return to Phase I limitations for a minimum of five hours.

The Order does not cite a basis for these guidelines, although FAA AC 90-89A describes 

a broad flight test program that includes a pre-flight phase with inspections and taxi tests, the 

important first flight, and subsequent periods of testing dictated by a series of test objectives.

5.3.2 Accidents During Phase I Flight Testing

Thirty-four of the E-AB aircraft accidents investigated during 2011 involved aircraft 

being operated in Phase I, ostensibly undergoing flight testing. Eight of these accidents occurred 

on the first test flight.58 Unfortunately, no information is available from these accidents regarding 

the flight test plan that was presumably being followed.

An example of an accident involving an E-AB aircraft in Phase I flight testing occurred 

on July 16, 2011, at 1930 eastern daylight time, when an amateur-built Dixon Volksplane VP-1, 

collided with a barn following a partial loss of engine power on takeoff from the Jackson County 

Airport in Jackson, Michigan. The pilot received minor injuries and the airplane was 

substantially damaged. The 14 CFR Part 91 flight was operating in visual meteorological 

conditions without a flight plan. The flight was originating at the time of the accident.59

The pilot reported he was making the first flight in the airplane, which was built by 

someone else. He stated that he inspected the airplane and paperwork and believed the airplane 

was satisfactory to fly. 

The pilot was cleared for takeoff on runway 32 and the winds were calm. He stated that 

the takeoff roll seemed sluggish, but he thought it was due to the warm outside temperature. The 

airplane lifted off about halfway down the 4,000-foot-long runway. He stated that the airplane 

was significantly left-wing heavy, but he was able to maintain control by applying right aileron. 

The airplane was out of ground effect when he reached the end of the runway, at which point the 

airspeed and engine power were decreasing very slowly. The pilot made a shallow turn in an 

attempt to land on runway 26. The engine continued to lose power and the airplane stalled at tree 

top height. The left wing contacted a pole barn, which spun the airplane around prior to it 

contacting the ground, resulting in substantial damage to the wings and fuselage. 

The Volkswagen engine was equipped with dual carburetors and an oil cooler. The 

mixture control setting was preset and was not adjustable from the cockpit. The airplane owner 

stated that he performed a teardown inspection on the engine following the accident and he was 

not able to identify any mechanical failures/malfunctions that would have resulted in the loss of 

engine power. No further engine examination was performed and the reason for the loss of power 

was not determined.60

 58 Two additional first-flight accidents involved unregistered aircraft with no airworthiness certification.

59 NTSB accident case number CEN11LA488.

60 The NTSB determined the probable cause of this accident (NTSB accident case number CEN11LA488) to be 

a partial loss of engine power during initial climb after takeoff for undetermined reasons.
NTSB The Safety of Experimental Amateur-Built Aircraft

72

Two of the 34 E-AB aircraft accidents involving aircraft operating in Phase I had been 

bought used before the Phase I testing period had been completed. Therefore, the new owner 

would have been required to complete the Phase I flight test requirements before conducting 

normal operations. In both of these cases, the purpose of the accident flight was described to the 

NTSB investigator as familiarization with the newly purchased aircraft, rather than performance 

of flight test activities. In one of these cases, this was the new owner‘s first flight. In neither of 

the cases had a new application for airworthiness certification been filed, or had a new 

Airworthiness Certificate for Operation of Amateur-Built Aircraft been issued. FAA 

Order 8130.2G is explicit in stating that the airworthiness certificate is transferred upon the sale 

of the aircraft and that ―there is no FAA inspection required after transfer of an aircraft with its 

airworthiness certificate, unless it is determined that revised operating limitations are 

necessary.‖61 It is not clear how, or by whom, such a determination that revised limitations are 

necessary would be made. The NTSB concludes that such transfers of ownership, and thus 

responsibility for the completion of flight test requirements during Phase I, do not ensure an 

opportunity for the FAA to review and accept the continuing appropriateness of Phase I 

operating limitations and requirements for the new owner of the aircraft.62

5.3.3 Loss of Control During Phase I Flight Testing

Loss of aircraft control in flight made a particularly large contribution to accidents early 

in the life of the aircraft involved in the 2011 case studies. Four of the eight fatal E-AB aircraft

accidents during Phase I flight testing in 2011 were associated with loss of control in flight. The 

NTSB concludes that the Phase I flight test period is uniquely challenging for most pilots 

because they must learn to manage the handling characteristics of an unfamiliar aircraft while 

also managing the challenges of the flight test environment, including instrumentation that is not 

yet calibrated, controls that may need adjustment, and possible malfunctions or adverse handling 

characteristics. FAA AC 90-89A, Amateur-Built Aircraft and Ultralight Flight Testing 

Handbook,

63 provides guidance for flight testing amateur-built aircraft and offers safety-related 

recommendations to assist amateur builders in developing individualized aircraft flight test plans.

5.3.4 Phase I Test Pilot Qualifications 

The aircraft builder was the test pilot in 29 of the 34 Phase I accidents during 2011. The 

majority (62 percent) of the 34 test pilots held a private pilot certificate, while 27 percent held 

commercial pilot certificates. The median age of these pilots was 62 years, the median hours of 

total flight time was 1,000 hours, and the median hours of experience in the accident make and 

model was 4 hours. Forty-four percent of these pilots had had no prior mechanical or building 

experience, 24 percent claimed previous E-AB aircraft building experience, 20 percent were 

A&P mechanics, and 12 percent reported military aviation experience. FAA AC 90-89A states

that Phase I flight test requirements should be performed by pilots who are ―rated, current and 

 61 FAA Order 8130.2G, Section 4102i.

62 This issue is considered further in a later section of this report, ―Providing Information to Purchasers of Used 

E-AB Aircraft.‖

63 http://www.faa.gov/library/manuals/aircraft/media/ac90-89a.pdf.
NTSB The Safety of Experimental Amateur-Built Aircraft

73

competent in the same category and class as the aircraft being tested.‖64 Test pilot flight time 

requirements suggested by FAA AC 90-89A are:

1. 100 hours of solo time before flight testing a kit plane or an aircraft built from a 

time-proven set of plans.

2. 200 hours of solo time before flight testing a  ̳one-of-a-kind‘ or high-performance 

aircraft.

3. A minimum of 50 recent takeoffs and landings in a conventional (tailwheel aircraft) if 

the aircraft to be tested is a tail dragger.

FAA AC 90-89A also recommends that the builder attach the same budgetary and time 

priority to obtaining and maintaining pilot competence as is assigned to the building project, if he 

or she intends to perform the test pilot functions. The NTSB concludes that the E-AB aircraft

safety record could be improved by providing pilots with additional training and guidance to 

safely perform Phase I test pilot functions. The EAA periodically offers a Sport Aviation 

Workshop titled Test Flying and Developing Pilot Operating Handbook. The focus of this course 

is to assist the builder/pilot to safely explore the aircraft‘s flight envelope, gather and interpret 

flight test data and develop the aircraft flight manual. The EAA‘s Flight Advisor Program also 

provides support to the builder/pilot in developing and executing a flight test program.

Therefore, the NTSB recommends that the FAA and the EAA identify and apply incentives to 

encourage owners, builders, and pilots of E-AB aircraft to complete flight test training, such as 

that available in the Experimental Aircraft Association‘s Test Flying and Developing Pilot 

Operating Handbook, prior to conducting flight tests of E-AB aircraft.

5.3.5 Additional Persons Onboard During Phase I Flight Testing

On September 27, 2011, at 1915 eastern daylight time, an Owen model Vans RV-10 

airplane, N499RV, was substantially damaged during a forced landing and post-impact ground 

fire near Marietta, Ohio. The pilot and passenger sustained serious injuries. The local flight 

departed Mid-Ohio Valley Regional Airport, near Parkersburg, West Virginia, at 1855.

According to the pilot, the purpose of the flight was to familiarize himself with the 

experimental amateur-built airplane. The pilot-rated passenger had contributed in the assembly 

of the airplane and subsequently completed about 20 hours of flight testing on the airplane before 

the accident flight. The pilot stated that after departure he completed 15–20 minutes of basic 

flight maneuvers before returning to the departure airport. After receiving a clearance from the 

tower controller, he reduced engine power to initiate a descent from 3,000 feet mean sea level. 

The passenger suggested using a higher engine power setting during the cruise-descent. As the 

pilot slowly increased engine power, they heard a loud bang from the engine and oil began 

covering the windscreen. He noted that the engine continued to run erratically, but engine speed 

could not be controlled using the throttle or propeller controls. The pilot relinquished control of 

the aircraft to the passenger, who had more experience in the accident airplane, and a forced 

 64 http://www.faa.gov/library/manuals/aircraft/media/ac90-89a.pdf.
NTSB The Safety of Experimental Amateur-Built Aircraft

74

landing was made to a nearby wooded area. The airplane was extensively damaged during a 

post-impact ground fire.

In this and one other Phase I accident during 2011, there were two individuals aboard the 

accident aircraft, in apparent conflict with the operating limitation that, ―During the flight testing

phase, no person may be carried in this aircraft during flight unless that person is essential to the 

purpose of flight.‖ In the other Phase I accident with two persons on board, the second individual 

was described as a copilot/observer who was involved with the building of the aircraft. While 

FAA Order 8130.2G does not precisely define ―essential to the purpose of flight,‖ it is generally 

understood that this provision does not encompass training of the E-AB aircraft builder. The 

position taken by the EAA in response to a question posed to its home-builders website was as 

follows:65

We concur with the FAA that during all flight testing only the test pilot is allowed 

in the aircraft. We have yet to see a homebuilt aircraft that requires a co-pilot. If 

flight data needs to be recorded, make use of a tape recorder or other recording 

device to record flight data, e.g., airspeeds, engine instrument readings, etc.

While it is true that virtually all E-AB aircraft are single pilot aircraft, it is likely that the 

safety and efficiency of some Phase I flight test activities would be enhanced by the presence, in 

the cockpit, of two qualified pilots.

Results of accident data analyses, FAA guidance materials, and the qualitative feedback 

from subject matters experts, such as the EAA Builder‘s Council, indicate that even experienced 

pilots are at a particularly high risk of accidents early in the life of a new E-AB aircraft. Some 

builders have sought the assistance of another pilot to assist in the flight test process, but 

FAA Order 8130.2G currently prohibits anyone other than the pilot to occupy an aircraft during 

the Phase 1 flight test period. The NTSB agrees with the EAA position that transition training 

should not be combined with Phase I flight testing requirements. However, the NTSB believes 

that the safety of E-AB aircraft flight testing could be improved for some pilots and flight test 

circumstances if a qualified second pilot was authorized to accompany the pilot for the purpose 

of flight testing and not training. Other countries specify provisions for more than one pilot to 

occupy an aircraft during flight testing. For example, the U.K.‘s CAP 659 advises that: 

If you need an additional crewmember for a particular flight test, then specify this 

in your flight test programme and have it agreed by the CAA‘s Test Pilot and the 

[Regional Office] Surveyor. When agreed, we will list this need in the operating 

limitations on your Permit to Fly for Test.

FAA AC 20-27G contains language similar to this statement from CAP 659; however, no 

related guidance is provided to ASIs or DARs in Order 8130.2G. Providing pilots with a clearly 

defined policy regarding authorizing the presence of a second pilot would enhance flight safety 

during portions of the flight test program that simultaneously demand high levels of piloting skill 

and the capture of necessary flight test data. Therefore, the NTSB recommends that the FAA 

 65 http://members.eaa.org/home/homebuilders/faq/3Pilot%20Checkouts%20during%20the%20flight%20test%

20period.html.
NTSB The Safety of Experimental Amateur-Built Aircraft

75

revise Order 8130.2G, and related guidance or regulations, as necessary, to clarify those 

circumstances in which a second qualified pilot could be authorized to assist in the performance 

of flight tests when specified in the flight test plan and Phase I operating limitations.

5.3.6 Completion of Phase I Flight Testing

FAA Order 8130.2G states that an explicit flight test program must be accomplished 

before E-AB aircraft are issued an airworthiness certificate and Phase I operating limitations can 

enter the less restrictive Phase II operating limitations.

Showing Compliance to 14 CFR 91.319(b).66 The applicant should be advised 

that after the experimental amateur-built airworthiness certificate has been issued, 

they must show compliance to 14 CFR 91.319(b). This is done by developing a 

flight test program that addresses the requirements, goals, and objectives of each 

test flight. The flight test program should be developed in accordance with 

AC 90-89, Amateur-Built Aircraft and Ultralight Flight Testing Handbook, or its 

equivalent in scope and detail. Flight test programs serve two purposes:

They ensure the aircraft has been adequately tested and determined to be safe to 

fly within the aircraft‘s flight envelope.

The flight test data is used to develop an accurate and complete aircraft flight 

manual and to establish emergency procedures.

The owner/builder‘s self-endorsement in the aircraft logbook and maintenance records, 

stating that the prescribed flight hours were completed, is the only explicit evidence that the 

aircraft has been shown to comply with 14 CFR 91.319(b). There is no requirement that the ASI 

or DAR confirm this claim.

The UK‘s CAP 659, in comparison, provides that:

Once the flight test programme has been completed and the CAA‘s Test Pilot has 

accepted your flight test results, the Design Surveyor needs to be informed so that he 

can finalise any design approvals outstanding for your aircraft. He will also liaise

with our Test Pilot to ensure that your flight manual is acceptable to us.

When the Design Surveyor has completed and issued any outstanding design 

approvals and the flight manual has been approved, the RO Surveyor will issue the 

full Permit to Fly67 for your aircraft

In addition to the guidance provided by FAA AC 90-89A, the EAA, many kit 

manufacturers, and type clubs also provide guidance and training directed toward the 

 

66 Title 14 CFR 91.319(b) prescribes operating limitations of aircraft having experimental airworthiness 

certificates. The FAA may authorize changes to the operating limitations of 14 CFR 91.319 through special 

operating limitations issued to an individual aircraft.

67 Comparable to the authorization provided by the U.S. Phase II operating limitations.
NTSB The Safety of Experimental Amateur-Built Aircraft

76

development and conduct of a flight test plan and the preparation of an aircraft flight manual.

One of EAA‘s Sport Aviation Workshops, for example, is a two-day course titled Test Flying & 

Developing Pilot Operating Handbook.

68 FAA AC 90-89A advises builders that:

It is imperative a flight manual describing the anticipated performance of the 

aircraft be written by the aircraft builder/kit manufacturer. The manual will be 

revised several times during the flight test phase until it accurately reports the 

aircraft‘s performance.

The NTSB concludes that because no mechanism, other than the builder‘s 

self-certification, currently exists to ensure that the aircraft has been adequately tested and 

determined to be safe to fly within the aircraft‘s flight envelope or that the flight test data is used 

to develop an accurate and complete aircraft flight manual and to establish emergency 

procedures, it is likely that these flight test objectives are not achieved for some E-AB aircraft.

The NTSB further concludes that the risk of E-AB aircraft accidents could be reduced by 

verifying that all E-AB aircraft are adequately tested according to a flight test plan, and that the 

resulting test data are used to create an accurate and complete aircraft flight manual. Therefore, 

the NTSB recommends that the FAA revise Order 8130.2G, and related guidance or regulations, 

as necessary, to require the review and acceptance of the completed test plan documents and 

aircraft flight manual (or its equivalent) that documents the aircraft‘s performance data and 

operating envelope, and that establishes emergency procedures, prior to the issuance of Phase II 

operating limitations.

5.3.7 Use of Recorded Data for Phase I Flight Testing and Continued 

Airworthiness

FAA AC 90-89A describes, in general terms, the tests to be performed to explore the 

aircraft‘s flight envelope but does not prescribe specific parameters to be measured or data to be 

collected. Since FAA AC 90-89A was published on May 24, 1995, a number of technological 

improvements to such data collection have been introduced. Citing these data recording 

capabilities in its 2010 safety study of the introduction of glass cockpit avionics into light 

aircraft,69 the NTSB concluded, ―Some glass cockpit displays include recording capabilities that 

have significantly benefited accident investigations and that provide the general aviation 

community with the ability to improve equipment reliability and the safety and efficiency of 

aircraft operations through data analyses.‖ 

Similarly, a number of manufacturers make electronic flight information systems and 

primary flight displays that provide capable and sophisticated electronic recording of 

aerodynamic and engine parameters that can greatly facilitate the collection of data needed to 

carefully map the E-AB aircraft‘s flight envelope and performance characteristics. Glass cockpit 

avionics were reported by 16 percent of EAA survey respondents who had bought used aircraft, 

35 percent of respondents who had finished their E-AB aircraft, and 58 percent of respondents 

 68 http://www.sportair.com/schedule.html.

69 National Transportation Safety Board. 2010. Introduction of Glass Cockpit Avionics into Light Aircraft. Safety 

Study NTSB/SS-10/01. Washington, DC. Available: <http://www.ntsb.gov/doclib/safetystudies/SS1001.pdf>.
NTSB The Safety of Experimental Amateur-Built Aircraft

77

who were in the process of building their aircraft. Among the 2011 accident aircraft, 34 percent

of the built-by-owner aircraft were equipped with glass cockpit instruments compared with 

14 percent of the bought-used accident aircraft. 

Van‘s Aircraft, for example, publishes a flight test data template and sample flight test 

data for RV-12 on their website, based on the data-recording capabilities of the Dynon EFIS 

systems that are included with this kit. The NTSB concludes that data obtained from glass 

cockpit avionics, electronic flight instruments, or other recording devices can significantly 

enhance the efficient accomplishment of flight test objectives, as well as the monitoring of 

parameters important to the continuing airworthiness of the E-AB aircraft, provided that they are 

demonstrated to be precise and reliable, record at sufficiently high sampling rates, and are easily 

downloaded by the aircraft owner. Therefore, the NTSB recommends that the FAA revise 

AC 90-89A, Amateur-Built Aircraft and Ultralight Flight Testing Handbook, to include guidance 

for the use of recorded flight data for the purposes of flight testing and maintaining continued 

airworthiness of experimental aircraft. The NTSB further recommends that once developed, the 

FAA revise Order 8130.2G, and related guidance or regulations, as necessary, to include 

provisions for the use of electronic data recordings from electronic flight displays, engine 

instruments, or other recording devices in support of Phase I flight testing of E-AB aircraft to 

document the aircraft performance data and operating envelope and develop an accurate and 

complete aircraft flight manual.

The NTSB also recommends that the EAA work with its membership, aircraft kit 

manufacturers, and avionics manufacturers to develop standards for the recording of data in 

electronic flight displays, engine instruments, or other recording devices to be used in support of 

flight tests or continued airworthiness of E-AB aircraft.

5.4 Training and Information to Prevent Loss of Control in Flight 

As previously noted, the largest proportion of fatal E-AB aircraft accidents has 

historically involved loss of aircraft control in flight. The study identified several opportunities to 

reduce loss of control accidents by improving pilots‘ access to training prior to flying an E-AB 

aircraft, and ensuring that pilots have the performance information necessary to safely operate 

their E-AB aircraft.

5.4.1 Transition Training

The FAA and the EAA, as well as several E-AB aircraft kit manufacturers and aircraft 

type clubs, strongly encourage specific training for pilots transitioning to E-AB aircraft and 

provide information and resources to support this training. Transition training is needed to 

prepare E-AB aircraft pilots for the unique handling characteristics of their aircraft. According to 

the EAA, the network of advisors comprising its Flight Advisor program, 70

...helps with everything from finding the right instructor and planning a first 

flight to determining the types of additional training needed. More than 500 flight 

 70 http://www.eaa.org/flightadvisors/.
NTSB The Safety of Experimental Amateur-Built Aircraft

78

advisors council members considering purchasing an aircraft, preparing for flight 

in a newly built or restored aircraft, or looking to transition to a high performance 

or unfamiliar aircraft. 

In the summer of 2011, representatives of the EAA, pilot groups, and owner type clubs 

announced the intention to form a coalition to improve safety. One of the planned efforts is to 

specifically seek out pilots transitioning to new aircraft to notify them of model-specific safety 

information and how to obtain transition training.71

In March 2011, the FAA also published AC 90-109, Airmen Transition to Experimental 

or Unfamiliar Airplanes, to be used as a guide for pilots flying an aircraft for the first time, with 

an emphasis on amateur-built experimental aircraft. Analysis of responses to the EAA survey of 

E-AB aircraft owners and builders indicates that 1,499 (58 percent) of the 2,583 respondents who 

built their E-AB aircraft and who answered the question reported some type of transition training 

prior to their first flight. In contrast, NTSB investigators found evidence of a transition training 

requirement—typically from an aircraft insurance company—for only 19 (8 percent) of the 

227 pilots of E-AB accident aircraft investigated in 2011. While the lack of evidence for 

transition training or an insurance training requirement on the basis of accident investigation 

records may underestimate the actual incidence of such training (particularly for fatal accidents 

where the pilot could not be interviewed), the reported proportion is strikingly low. The NTSB 

concludes that the difference between the EAA survey respondents and the 2011 accident pilots 

suggests that pilots who did not seek training were overrepresented in the accidents, and that 

E-AB aircraft accidents involving of loss of aircraft control could be reduced if more pilots 

received transition training.

5.4.2 Barriers to E-AB Aircraft Transition Training

During focus group discussions with NTSB investigators during EAA AirVenture 2011, 

members of the EAA Builder‘s Council stressed the importance of transition training for any 

pilot transitioning from one type of aircraft to another. They noted that this is particularly true of 

E-AB aircraft, which frequently have different handling characteristics than the type-certificated

aircraft with which pilots may be familiar.72 Members of the Builder‘s Council referenced 

regulations regarding the use of experimental aircraft that limit pilot‘s access to transition 

training. Specifically, they referred to limitations in 14 CFR 91.319, which states: 

(a) No person may operate an aircraft that has an experimental certificate—(1) 

For other than the purpose for which the certificate was issued; or (2) Carrying 

persons or property for compensation or hire. 

As referenced in that limitation, 14 CFR 21.191 states that experimental certificates are 

issued for the following purposes: 

 71 http://www.airventure.org/news/2011/110729_type_clubs.html.

72 The need for focused transition training was the object of recommendations A-99-007 and A-99-009, which 

were issued in 1999, and classified ―Closed—Acceptable Action‖ in 2000 and 2001 respectively. These 

recommendations resulted from the NTSB investigation (LAX98FA008) of an accident on October 12, 1997, near 

Pacific Grove, California, involving an experimental amateur-built Adrian Davis Long-EZ. The aircraft was piloted 

by singer John Denver, who was fatally injured as a result of the accident.
NTSB The Safety of Experimental Amateur-Built Aircraft

79

Research and development. 

Showing compliance with regulations. 

Crew training. 

Exhibition. 

Air racing. 

Market surveys. 

Operating amateur-built aircraft. 

Operating primary kit-built aircraft. 

Operating light-sport aircraft (LSA). 

Guidance to FAA inspectors in FAA Order 8900.173 explicitly states that the term 

―crew training‖ in section 21.191 does not permit for-hire pilot flight training. The inspector 

guidance in FAA Order 8900.1 further states: 

Use of Experimental Aircraft for Flight Training. Persons may receive, and 

provide compensation for, flight training in an aircraft holding an experimental 

certificate issued for any of the purposes specified in section 21.191. Other than 

the person receiving flight training, the operation must not involve the carriage of 

persons or property for compensation or hire or be prohibited by the aircraft‘s 

operating limitations.

Flight Instructors. Flight instructors may receive compensation for providing 

flight training in an experimental aircraft, but may not receive compensation for 

the use of the aircraft in which they provide that flight training unless in 

accordance with a LODA issued under section 91.319(h) and as described in 

paragraph 3-293. An experimental aircraft owner may not rent an experimental 

LSA to a person for the purpose of conducting solo flight.

Experimental Aircraft Owners. Owners of experimental aircraft may receive, 

and provide compensation for, flight training received in their aircraft. An owner 

of an experimental aircraft may not receive compensation for the use of their 

aircraft to provide flight training except in accordance with a LODA issued under 

[section] 91.319(h) and described in paragraph 3-293. An owner of an 

experimental LSA may not rent the experimental LSA to a person for the purpose 

of conducting solo flights.

 73 FAA Order 8900.1, Flight Standards Information Management System (FSIMS) CHG 155, May 24, 2011,

Use of Aircraft Issued Experimental Certificates in Flight Training for Compensation or Hire, 

http://fsims.faa.gov/wdocs/8900.1/v03%20tech%20admin/chapter%2011/03_011_001.pdf.
NTSB The Safety of Experimental Amateur-Built Aircraft

80

The LODA mentioned in this section is referencing a Letter of Deviation Authority. 

Title 14 CFR 91.319(h) permits the FAA to issue a LODA to an applicant for the purpose of 

conducting flight training. A LODA permits the holder to provide flight training for 

compensation in an experimental aircraft which the holder provides. Based on discussions with 

members of the EAA Builder‘s Council, E-AB aircraft builders, kit manufacturers and type club 

representatives, the NTSB concludes that the guidance currently available to qualified E-AB 

aircraft owner/instructors to obtain a LODA to conduct flight training is deficient and variable 

from one FAA region to another. Based on discussions, the NTSB concludes that the difficulty 

of finding suitable E-AB aircraft and instructors available for training presents a barrier to pilots 

seeking transition training. Therefore, the NTSB recommends that the FAA develop and publish 

an advisory circular, or similar guidance, for the issuance of a LODA to conduct flight 

instruction in an experimental aircraft, to include sample documentation and sample training 

materials. The NTSB also recommends that the EAA create and publish a repository of 

voluntarily provided information regarding holders of LODAs to conduct flight instruction in 

experimental aircraft.

The NTSB acknowledges that the development of guidance materials and related 

regulatory actions will likely require considerable time. However, voluntary efforts such as the 

planned creation of a coalition of kit manufacturers could assist in the promotion of transition 

training in the interim. Therefore, the NTSB recommends to the FAA and the EAA that they 

complete planned action74 to create a coalition of kit manufacturers, type clubs, and pilot and 

owner groups and (1) develop transition training resources and (2) identify and apply incentives 

to encourage both builders of E-AB aircraft and purchasers of used E-AB aircraft to complete the 

training that is developed.

5.4.3 Providing Information to Purchasers of Used E-AB Aircraft

On August 25, 2011, at 1856 eastern daylight time, a Nichols model Lancair 235 

airplane, N777BN, was substantially damaged when it impacted trees and terrain during initial 

climb from Newark-Heath Airport, Heath, Ohio. The pilot was fatally injured. The airplane was 

registered to and operated by a private pilot, under the provisions of 14 CFR Part 91. Daytime 

visual meteorological conditions prevailed for the flight, which was operated without a flight 

plan. The local flight was originating at the time of the accident. 

A witness stated that the airplane appeared to be ―very unstable‖ after it became airborne, 

alternately rolling right and left while remaining only a few feet above the runway. The witness 

noted that he did not believe the pilot had control of the airplane. The airplane then turned left 

and proceeded off the runway directly toward the witness‘s position. The witness noted that the 

airplane continued to fly erratically, with continuous pitch, yaw, and roll changes, and cleared a 

row of hangars by approximately 10 feet. The airplane continued in a climb to 100–150 feet 

above the ground before it banked sharply to the left and entered a nose-down descent into trees. 

 74 http://www.airventure.org/news/2011/110729_type_clubs.html.
NTSB The Safety of Experimental Amateur-Built Aircraft

81

The experimental amateur-built airplane had accumulated 1,131 hours since being issued 

an airworthiness certificate on August 10, 1990. The pilot reportedly had not flown the airplane 

since he purchased it from the original builder on September 14, 2010.75

In FAA AC 90-109, regarding pilots transitioning to unfamiliar aircraft, the FAA states: 

Current accident analysis indicates that subsequent owners and/or pilots of 

experimental airplanes, during initial flight time, have a higher accident rate than 

that of the original owner/pilot. Therefore, the recommendation is that the 

subsequent owners/pilots of experimental airplanes receive airplane-specific 

training before operating the airplane. 

Fifty-five percent (125 of 227) of the 2011 accident aircraft had been bought used, but it 

was not possible, on the basis of available data, to determine if the risk was higher for this group 

than for the original builders of E-AB aircraft. FAA AC 90-109 goes on to state:

The new buyer of an experimental airplane may not fully understand the 

challenges of transitioning to a new airplane, particularly one which has 

characteristics outside his or her previous aviation experience. 

The NTSB concludes that purchasers of used E-AB aircraft face particular challenges in 

transitioning to the unfamiliar E-AB aircraft. Like builders of new E-AB aircraft, they must learn 

to manage the unique handling characteristics of their aircraft, but they must also learn the 

systems, structure, and equipment without the firsthand knowledge afforded to the builder. In 

this regard, FAA AC 90-109 states that, to become familiar and competent in the new airplane, 

pilots should follow an organized methodology that includes the systems, procedures, 

performance, and limitations applicable to their aircraft. However, this guidance includes a 

caution that:

Even in simple airplanes of a similar design or even the same model, the 

innovation of individual designers and builders may cause problems for a pilot 

new to the airplane. 

Pilots of type-certificated aircraft have access to the applicable aircraft and systems 

information in the Pilot’s Operating Handbook developed by the airplane manufacturer, which 

contains the FAA-approved aircraft flight manual. However, unless the original builder of an 

E-AB aircraft creates similar materials during the course of aircraft flight testing, a subsequent 

owner may not have the detailed aircraft information necessary to support safe operation during 

transition to the aircraft and subsequent operation of the aircraft. The NTSB concludes that 

accident case studies included in this report indicate that not all builders of E-AB aircraft create a 

detailed aircraft flight manual during Phase I flight testing. 

For example, on March 29, 2011, about 1630 eastern daylight time, an experimental 

amateur-built Hrosik Aventura II, N5842, was substantially damaged during a collision with 

terrain after takeoff from Thunderbird Air Park, Crescent City, Florida. The certificated sport 

 75 NTSB investigation case number CEN11FA597.
NTSB The Safety of Experimental Amateur-Built Aircraft

82

pilot sustained a minor injury. In a written statement, the pilot said the purpose of the flight was 

to position the amphibious airplane at the Sun  ̳n Fun Fly-In so that it could be offered for 

auction. According to the FAA inspector, there was no checklist for the airplane, no placarded 

V-speeds in the cockpit, and no color-coded airspeed range markings on the airspeed indicator.76

As discussed earlier in this chapter, the development of a detailed aircraft flight manual is an 

intended product of E-AB aircraft flight testing. The NTSB concludes that absent an appropriate 

aircraft flight manual, purchasers of used E-AB aircraft are not provided with sufficient 

information to understand the aircraft‘s controllability throughout all maneuvers, to detect any 

hazardous operating characteristics, or to understand emergency procedures.

Therefore, the NTSB recommends that the FAA revise 14 Code of Federal 

Regulations 47.31 and related guidance or regulations, as necessary, to require the review and 

acceptance of aircraft operating limitations and supporting documentation as a condition of 

registration or re-registration of an experimental amateur-built aircraft. The NTSB also 

recommends that the FAA revise Order 8130.2G, and related guidance or regulations, as 

necessary, to include provisions for modifying the operating limitations of aircraft previously 

certificated as experimental, operating amateur-built, such as returning the aircraft to Phase I flight 

testing, as necessary, to address identified safety concerns or to correct deficiencies in the aircraft 

flight manual or equivalent documents.

5.5 Accurate Identification of Amateur-Built Aircraft 

Finally, the study found problems related to the accurate identification of amateur-built 

aircraft, and the aircraft make and model, that currently make effective E-AB aircraft safety 

oversight difficult. Section 501(a) of the Federal Aviation Act of 1958, as amended, codified at 

section 44102(b) of title 49, United States Code, requires registration as a condition to the 

operation of any applicable aircraft, and this Statutory requirement is implemented by the 

14 CFR Parts 47 and 49 that include regulations for aircraft registration and related 

documentation.

Title 14 CFR 49.11 establishes the FAA Aircraft Registry as the official custodian of 

U.S. aviation aircraft records. The FAA Flight Standards Service, Civil Aviation Registry, 

Aircraft Registration Branch is responsible for the review, evaluation, and development of any 

new or amended regulations pertaining to aircraft registration and recording of documents 

contained in 14 CFR Parts 47 and 49. The registry provides information to FAA Aviation Safety 

Inspectors and NTSB investigators to support aviation safety activities and provides statistics for 

aviation safety analyses. Registry records are also a source of aircraft owner contact information 

to publicize aircraft- or fleet-specific safety programs or safety concerns.77

The registry maintains a publicly available database containing fields identifying each 

U.S. registered aircraft by its current registration number, its unique airframe serial number, and 

characteristics like category and engine type. Aircraft type is identified in the registry with the 

combination of two fields, aircraft manufacturer and aircraft model, and the FAA uses the 

 76 NTSB investigation case number ERA11LA228.

77 http://www.faa.gov/about/office_org/headquarters_offices/avs/offices/afs/afs700/reg_responsibilities/.
NTSB The Safety of Experimental Amateur-Built Aircraft

83

combination of these details to assign a manufacturer-model code that is also recorded in the 

registry. For type-certificated aircraft, the manufacturer field identifies the aircraft builder and 

the model field indicates the model and series. For example, the Registry database fields for a 

common type-certificated light aircraft would be Cessna Aircraft Company for the manufacturer

and 172S for the model. 

When registering a new E-AB aircraft, the aircraft owner/builder must submit: 

An Affidavit of Ownership for Experimental Aircraft, AC Form 8050-88,78

establishing ownership and the formal description of the aircraft. The model name 

and serial number provided on this form by the builder, along with the builder‘s 

name, becomes the official aircraft description.

An Aircraft Registration Application, AC Form 8050-1,

79 containing the same aircraft 

description provided on the affidavit.

And, if more than 50 percent of your amateur-built aircraft was built from a kit, the 

owner must also include a kit bill of sale from the kit manufacturer.

Unlike a type-certificated aircraft, when a builder registers an amateur-built aircraft he or 

she is free to choose a manufacturer and model name to identify their aircraft regardless of the 

aircraft design. For example, the builder of an experimental amateur-built kit, such as a Van‘s 

Aircraft RV-9 kit, may register the aircraft as John Doe for the manufacturer and Model 1 for the 

model. The design of the original kit would not be identifiable from the registry database record, 

even though the kit bill of sale is required to be submitted during registration and is retained in 

the registry‘s records. As discussed in chapter 3 and appendix C of this report, incorrect 

identification of E-AB aircraft in NTSB accident records has affected the tracking and analysis 

of E-AB aircraft safety issues and the problem has increased since the introduction of the Special 

Light-Sport and Experimental Light-Sport certification categories. 

The ability to accurately identify E-AB aircraft built from a kit or from plans of a 

recognized design would be greatly improved if the FAA Civil Aircraft Registry database were 

modified to capture aircraft manufacturer, make, and model.80 Although the terms are often used 

interchangeably, manufacturer and make are not synonymous. With regard to aircraft, ―make‖ 

identifies an aircraft design and ―manufacturer‖ identifies the entity that constructs an aircraft. 

As applied to the previous example, the addition of make information would allow identification 

of the previous example John Doe Model 1 as being a Van‘s Aircraft kit. 

The addition of aircraft make information to the FAA Civil Aircraft Registry database 

would also improve the identification of type-certificated aircraft that are produced by more than 

one manufacturer. The CAST/ICAO Common Taxonomy Team (CICTT) has developed 

 78 http://www.faa.gov/licenses_certificates/aircraft_certification/aircraft_registry/media/8050-88.pdf.

79 http://www.faa.gov/licenses_certificates/aircraft_certification/aircraft_registry/faa_customer_service_

forms/##ACForm8050-1.

80 The NTSB identified similar concerns regarding identification of E-AB aircraft kits owners in its August 29, 1997, 

Safety Recommendation letter to the FAA (A-97-53, ―Closed—Acceptable Action,‖ December 1998).
NTSB The Safety of Experimental Amateur-Built Aircraft

84

business rules for the identification of aircraft. The CICTT aircraft make/model/series taxonomy 

has been included in the ECCAIRS81 software suite used by ICAO and aviation safety authorities 

worldwide to manage safety data and is used to identify aircraft in the International Registry of 

Mobile Assets.82

The inability to identify the aircraft design in the FAA Civil Aircraft Registry limits the 

ability to conduct safety analyses and hampers notification of aircraft owners in the event that an 

aircraft- or engine-specific issue is ever identified. The NTSB concludes that accurate 

identification of experimental amateur-built aircraft would greatly improve the ability to assess 

the continued safety of experimental aircraft and identify design-specific safety issues. 

Therefore, the NTSB recommends that the FAA revise the Civil Aircraft Registry database to 

include a means of identifying aircraft manufacturer, make, model, and series—such as the 

aircraft make, model, and series classification developed by the CAST/ICAO Common 

Taxonomy Team—that unambiguously identifies the aircraft kit or plans design as well as the 

builder of the aircraft.

 81 European Coordination Centre for Accident and Incident Reporting Systems (ECCAIRS) is a cooperative 

network of international Transport Authorities and Accident Investigation Bodies. The project is being managed by 

the Joint Research Centre (JRC) of the European Commission. The ECCAIRS Reporting System, developed by the 

JRC, is a software suite used for reporting, analysis, and sharing of safety data. For additional information, see: 

http://eccairsportal.jrc.ec.europa.eu/.

82 The International Registry operates under the legal framework of the Cape Town Convention and the Aircraft 

Protocol adopted on the 16th of November 2001 at Cape Town. It provides for the registration and protection of 

 ̳international interests‘ that are recognized by all ratifying states, of which the United States of America is included. 

Aircraft and aircraft engines eligible for International Registry recording include airframes that are type certificated 

to transport at least eight persons including crew or goods in excess of 2,750 kilograms (6,050 pounds); helicopters 

that are type certificated to transport at least five persons including crew or goods in excess of 450 kilograms 

(990 pounds); jet propulsion aircraft engines with at least 1,750 pounds of thrust or its equivalent; and 

turbine-powered or Piston-powered aircraft engines with at least 550 rated take-off horsepower or its equivalent. For 

more information see: http://www.internationalregistry.aero.
NTSB The Safety of Experimental Amateur-Built Aircraft

85

6. Conclusions

Experimental amateur-built aircraft represents a growing segment of the United States‘ 

general aviation fleet. A review of the accident record indicates that E-AB aircraft account for a 

disproportionate number of total accidents, and an even more disproportionate share of fatal 

accidents when compared to similar non-E-AB aircraft conducting similar flight operations. By 

conducting a comprehensive review of E-AB aircraft safety, using a variety of information 

sources, this study was able to characterize the aircraft, builder, and pilot populations; assess 

safety resources and management; and identify areas for recommended improvement.

The airworthiness certification and maintenance of E-AB aircraft are managed according 

to a different regulatory and policy framework than non-E-AB aircraft. The experimental nature 

of amateur-built aircraft is evident in the wide range of powerplants, equipment, and design 

features found in these aircraft. Accident analyses indicate that powerplant failures and loss of 

control in flight are the most common accident occurrences by a large margin, and that accident 

occurrences are similar for both new and used aircraft. However, it is notable that structural 

failures have not been a common occurrence among E-AB aircraft. Accidents involving 

equipment failures or build problems are instead frequently associated with unique decisions 

made by an individual owner or builder. The majority of new E-AB aircraft are now built from 

commercial kits, a fact that has likely contributed to an overall improvement in the design and 

construction of E-AB aircraft. Kit manufacturers also represent a potential source of valuable 

construction, flight testing, operation, and maintenance information.

The community of E-AB aircraft builders and owners is actively involved in their own 

safety oversight and management. Builder groups, aircraft type clubs, kit manufacturers, and 

industry associations provide a wealth of training and guidance materials to pilots and builders. 

The FAA has also published guidance materials to assist builders, to promote thorough flight testing of 

E-AB aircraft, and to encourage pilots to seek necessary transition training. Pilots of E-AB

aircraft, whether involved in accidents or not, have similar, or higher, levels of total aviation 

experience than pilots of non-E-AB aircraft engaged in similar general aviation operations. 

However, pilots of E-AB aircraft, on average, had significantly less flight experience in the type 

of aircraft they were flying. The difference in type-specific experience is likely due to the 

uniqueness of the aircraft they are flying. The prevalence of accidents involving E-AB aircraft 

very early in their operational life, or after being purchased by a new owner, highlights the need 

for training and information to safely operate these unique aircraft. 
NTSB The Safety of Experimental Amateur-Built Aircraft

86

6.1 Findings

1. The risk of E-AB aircraft accidents could be reduced by verifying that all E-AB aircraft are 

adequately tested according to a flight test plan, and that the resulting test data are used to 

create an accurate and complete aircraft flight manual.

2. Data obtained from glass cockpit avionics, electronic flight instruments, or other recording 

devices can significantly enhance the efficient accomplishment of flight test objectives, as 

well as the monitoring of parameters important to the continuing airworthiness of the E-AB 

aircraft, provided that they are demonstrated to be precise and reliable, record at sufficiently 

high sampling rates, and are easily downloaded by the aircraft owner.

3. A functional test of the aircraft fuel system could identify design deficiencies, leaks, and 

malfunctions prior to flight that would prevent fuel system- and powerplant-related accidents 

early in the operational life of an aircraft.

4. Accident case studies included in this report indicate that not all builders of E-AB aircraft 

create a detailed aircraft flight manual during Phase I flight testing.

5. Absent a review and assessment by the FAA, the adequacy of the flight test program 

stipulated in Order 8130.2G cannot be ascertained or ensured. 

6. The Phase I flight test period is uniquely challenging for most pilots because they must learn 

to manage the handling characteristics of an unfamiliar aircraft while also managing the 

challenges of the flight test environment, including instrumentation that is not yet calibrated, 

controls that may need adjustment, and possible malfunctions or adverse handling 

characteristics.

7. The E-AB aircraft safety record could be improved by providing pilots with additional 

training resources to safely perform Phase I test pilot functions. 

8. The safety of E-AB aircraft flight testing could be improved for some pilots and flight test 

circumstances if a qualified second pilot was authorized to accompany the pilot for the 

purpose of flight testing and not training.

9. Because no mechanism, other than the builder‘s self-certification, currently exists to ensure 

that the aircraft has been adequately tested and determined to be safe to fly within the 

aircraft‘s flight envelope or that the flight test data is used to develop an accurate and 

complete aircraft flight manual and to establish emergency procedures, it is likely that these 

flight test objectives are not achieved for some E-AB aircraft.

10. The difference between the EAA survey respondents and the 2011 accident pilots suggests 

that pilots who did not seek training were overrepresented in the accidents, and that E-AB 

aircraft accidents involving loss of aircraft control could be reduced if more pilots received 

transition training.

11. The difficulty of finding suitable E-AB aircraft and instructors available for training presents 

a barrier to pilots seeking transition training.
NTSB The Safety of Experimental Amateur-Built Aircraft

87

12. The FAA guidance currently available to qualified E-AB aircraft owner/instructors to obtain 

a Letter of Deviation Authority to conduct flight training is deficient and variable from one 

FAA region to another.

13. Purchasers of used E-AB aircraft face particular challenges in transitioning to the unfamiliar 

E-AB aircraft. Like builders of new E-AB aircraft, they must learn to manage the unique 

handling characteristics of their aircraft and learn the systems, structure, and equipment, but

without the firsthand knowledge afforded to the builder.

14. Transfers of ownership, and thus responsibility for the completion of flight test requirements 

during Phase I, do not ensure an opportunity for FAA review and acceptance of the 

continuing appropriateness of Phase I operating limitations and requirements for the new 

owner of the aircraft. 

15. Absent an appropriate aircraft flight manual, purchasers of used E-AB aircraft are not 

provided with sufficient information to understand the aircraft‘s controllability throughout all 

maneuvers, to detect any hazardous operating characteristics, or to understand emergency 

procedures.

16. Accurate identification of experimental amateur-built aircraft would greatly improve the 

ability to assess the continued safety of experimental aircraft and identify design-specific 

safety issues.
NTSB The Safety of Experimental Amateur-Built Aircraft

88

7. Recommendations

As a result of its safety study, the National Transportation Safety Board makes the 

following recommendations:

To the Federal Aviation Administration:

Revise 14 Code of Federal Regulations 21.193, Federal Aviation Administration 

Order 8130.2G, and related guidance or regulations, as necessary, to define 

aircraft fuel system functional test procedures and require applicants for an 

airworthiness certificate for a powered experimental, operating amateur-built 

aircraft to conduct that test and submit a report of the results for Federal Aviation 

Administration acceptance. (A-12-28)

Revise 14 Code of Federal Regulations 21.193, Federal Aviation Administration 

Order 8130.2G, and related guidance or regulations, as necessary, to require 

applicants for an airworthiness certificate for experimental, operating 

amateur-built aircraft to submit for Federal Aviation Administration acceptance a 

flight test plan that will (1) ensure the aircraft has been adequately tested and has 

been determined to be safe to fly within the aircraft‘s flight envelope and 

(2) produce flight test data to develop an accurate and complete aircraft flight 

manual and to establish emergency procedures and make a copy of this flight test 

plan part of the aircraft‘s certification file. (A-12-29)

Identify and apply incentives to encourage owners, builders, and pilots of 

experimental amateur-built aircraft to complete flight test training, such as that 

available in the Experimental Aircraft Association‘s Test Flying and Developing 

Pilot Operating Handbook, prior to conducting flight tests of experimental 

amateur-built aircraft. (A-12-30)

Revise Federal Aviation Administration Order 8130.2G, and related guidance or

regulations, as necessary, to clarify those circumstances in which a second 

qualified pilot could be authorized to assist in the performance of flight tests when 

specified in the flight test plan and Phase I operating limitations. (A-12-31)

Revise Federal Aviation Administration Order 8130.2G, and related guidance or 

regulations, as necessary, to require the review and acceptance of the completed 

test plan documents and aircraft flight manual (or its equivalent) that documents 

the aircraft‘s performance data and operating envelope, and that establishes 

emergency procedures, prior to the issuance of Phase II operating limitations.

(A-12-32)

Revise Federal Aviation Administration Advisory Circular 90-89A, 

Amateur-Built Aircraft and Ultralight Flight Testing Handbook, to include 

guidance for the use of recorded flight data for the purposes of flight testing and 

maintaining continued airworthiness of experimental aircraft. (A-12-33)
NTSB The Safety of Experimental Amateur-Built Aircraft

89

Revise Federal Aviation Administration Order 8130.2G, and related guidance or 

regulations, as necessary, to include provisions for the use of electronic data 

recordings from electronic flight displays, engine instruments, or other recording 

devices in support of Phase I flight testing of experimental amateur-built aircraft 

to document the aircraft performance data and operating envelope and develop an 

accurate and complete aircraft flight manual. (A-12-34)

Develop and publish an advisory circular, or similar guidance, for the issuance of 

a Letter of Deviation Authority to conduct flight instruction in an experimental 

aircraft, to include sample documentation and sample training materials.

(A-12-35)

Complete planned action to create a coalition of kit manufacturers, type clubs, and 

pilot and owner groups and (1) develop transition training resources and 

(2) identify and apply incentives to encourage both builders of experimental 

amateur-built aircraft and purchasers of used experimental amateur-built aircraft 

to complete the training that is developed. (A-12-36)

Revise 14 Code of Federal Regulations 47.31 and related guidance or regulations, 

as necessary, to require the review and acceptance of aircraft operating limitations 

and supporting documentation as a condition of registration or re-registration of 

an experimental amateur-built aircraft. (A-12-37)

Revise Federal Aviation Administration Order 8130.2G, and related guidance or 

regulations, as necessary, to include provisions for modifying the operating 

limitations of aircraft previously certificated as experimental, operating 

amateur-built, such as returning the aircraft to Phase I flight testing, as necessary,

to address identified safety concerns or to correct deficiencies in the aircraft flight 

manual or equivalent documents. (A-12-38)

Revise the Civil Aircraft Registry database to include a means of identifying 

aircraft manufacturer, make, model, and series—such as the aircraft make, model, 

and series classification developed by the CAST/ICAO Common Taxonomy 

Team—that unambiguously identifies the aircraft kit or plans design as well as the 

builder of the aircraft. (A-12-39)

To the Experimental Aircraft Association:

Identify and apply incentives to encourage owners, builders, and pilots of 

experimental amateur-built aircraft to complete flight test training, such as that 

available in the Experimental Aircraft Association‘s Test Flying and Developing 

Pilot Operating Handbook, prior to conducting flight tests of experimental 

amateur-built aircraft. (A-12-40)
NTSB The Safety of Experimental Amateur-Built Aircraft

90

Work with your membership, aircraft kit manufacturers, and avionics 

manufacturers to develop standards for the recording of data in electronic flight 

displays, engine instruments, or other recording devices to be used in support of 

flight tests or continued airworthiness of experimental amateur-built aircraft.

(A-12-41)

Create and publish a repository of voluntarily provided information regarding 

holders of Letters of Deviation Authority to conduct flight instruction in 

experimental aircraft. (A-12-42)

Complete planned action to create a coalition of kit manufacturers, type clubs, and 

pilot and owner groups and (1) develop transition training resources and (2) identify

and apply incentives to encourage both builders of experimental amateur-built 

aircraft and purchasers of used experimental amateur-built aircraft to complete the 

training that is developed. (A-12-43)
NTSB The Safety of Experimental Amateur-Built Aircraft

91

Appendix A: NTSB Aviation Accident Data 

Validation

NTSB staff reviewed records in the NTSB Aviation Accident Database83 to verify the 

aircraft airworthiness classification information relative to ―Experimental – Amateur-Built.‖ The 

NTSB Aviation Accident Database currently includes data fields to record aircraft airworthiness 

certificate type and category, such as ―Standard – Normal‖ or ―Special – Experimental.‖ 

However, the airworthiness data field does not include the additional level of detail necessary to 

distinguish between ―Special – Experimental – Amateur-Built‖ and other categories of 

Experimental certificates such as ―Exhibition‖, ―Air Racing‖, or ―Research and Development.‖ 

An additional yes/no field in the NTSB database, titled ―Homebuilt,‖ has historically been used 

to identify amateur-built accident aircraft. 

Although the field is intended to readily identify amateur-built aircraft, a summary 

review of NTSB database records reveals numerous cases in which the homebuilt field value was 

reported as ―yes‖ for aircraft with a special airworthiness certificate, but not in the amateur-built 

category. Errors and misapplications of the homebuilt code lead to an inaccurate assessment of 

the accident risk for amateur-built aircraft. In coordination with the FAA and the EAA, the 

NTSB used to the following methodology to validate the homebuilt yes/no data in the NTSB 

Aviation Accident Database records.

NTSB accident records from 2001 through 2010 were matched with archived, historic 

FAA aircraft registry records84 using aircraft registration, serial number, make, and 

model information, as available.

Aircraft airworthiness certificate data and the homebuilt yes/no field in the NTSB 

database were compared with the manufacturer model code85 and airworthiness 

certificate data in the FAA aircraft registry database to identify inconsistent data 

elements in either system. 

Copies of the original aircraft airworthiness and registration documents were used to 

validate the amateur-built status of those aircraft with missing or inconsistent FAA 

registry and/or NTSB accident database records.

 83 The NTSB maintains a database for the storage, retrieval, and management of information associated with its 

aviation accident/incident investigations. The NTSB Aviation Accident Database is comprised of 15 data tables, 

with approximately 350 data fields. The database currently contains approximately 70,000 cases, and approximately 

2,000 new cases are generated each year.

84 The FAA aircraft registry database contains the records of all U.S. civil aircraft maintained by the FAA, Civil 

Aviation Registry, Aircraft Registration Branch, AFS-750. The aircraft registry database is available for public 

download from the FAA website at: http://www.faa.gov/licenses_certificates/aircraft_certification/aircraft_

registry/releasable_aircraft_download/.

85 The FAA assigns a seven-digit code to each aircraft at the time of registration to identify the aircraft 

manufacturer, model, and series. The first three characters correspond to the manufacturer, the fourth and fifth 

characters refer to the model, and the sixth and seventh refer to the aircraft series.
NTSB The Safety of Experimental Amateur-Built Aircraft

92

This methodology resulted in the verification of 2,077 accident aircraft as E-AB aircraft, 

changes to indicate that 324 accident aircraft with missing or incorrect records are not E-AB 

aircraft, and changes to indicate that 46 accident aircraft with missing or incorrect records were, 

in fact, E-AB aircraft. The airworthiness status of an additional 138 accident aircraft could not be 

verified because they were unregistered, foreign registered, or did not have the necessary records 

on file for review.

In sum, the number of accident aircraft identified as E-AB aircraft in the NTSB records 

from 2001–2010 decreased by 278. However, not all of these cases are included in the 

United States civil general aviation accident record tabulations86. Figure A1 illustrates changes in 

the annual U.S. civil general aviation accident and fatal accident records from 2001 through 2010 

for cases involving E-AB aircraft.

Figure A1. Changes in the annual U.S. civil general aviation accident and fatal accident records 

for E-AB aircraft, 2001–2010.

The greatest number of E-AB aircraft data corrections were to accident records spanning 

2007 to 2009, suggesting that data errors increased with the introduction of the special light-sport 

aircraft category of airworthiness certificates in 2005 and the registration of ―fat ultralights‖ and 

two-seat ultralights previously exempted under a training provision of 14 CFR Part 10387. The 

 86 U.S. civil aviation accidents, as defined by 49 CFR Part 830.1, include accidents that involve U.S.-registered 

civil aircraft and certain public aircraft of the United States ―wherever they occur.‖ General aviation includes any 

civil aircraft operation that is not covered by 14 CFR Parts 121 or 135; or by Part 129, which applies to foreign air

carriers; or non-U.S. commercial operations.

87 See http://www.faa.gov/aircraft/gen_av/light_sport/.

3

-3

3 1

-9

-5

-28

-48

-34

-12

1

-3 -1

0

-4

-1

-7 -9 -7

-3

-60

-40

-20

0

20

40

60

Accidents 

Calendar Year

Results of NTSB Amateur Built Accident Data 

Validation, 2001-2010

E-AB Accidents Fatal E-AB Accidents
NTSB The Safety of Experimental Amateur-Built Aircraft

93

special light-sport aircraft (S-LSA) and experimental light-sport aircraft (E-LSA) fleets increased 

rapidly during this period, and these aircraft were subsequently involved in more accidents. A 

review of these aircraft-related data errors in the FAA and NTSB databases suggests initial 

misunderstandings among aircraft owners, inspectors, and investigators about this new aircraft 

classification. In other cases, identification was made more difficult because some popular 

aircraft models are available in E-AB, S-LSA, and/or E-LSA versions.

The net reduction in accident E-AB aircraft results in a slight reduction in calculated 

accident rates when compared with annual FAA estimates of E-AB aircraft flight hours.88 

Figure A2 illustrates the previous and revised U.S. civil general aviation accident rate for E-AB 

aircraft annually from 2001 through 2010, and Figure A3 shows the E-AB aircraft fatal accident 

rate.

Figure A2. Revised amateur-built aircraft accident rate following NTSB accident data validation, 

2001–2010.

 88 Flight activity of general aviation and nonscheduled Part 135 operations is estimated using the annual 

General Aviation and Part 135 Activity Survey. This voluntary survey is sent to registered aircraft owners.

http://www.faa.gov/data_research/aviation_data_statistics/general_aviation/.‖
NTSB The Safety of Experimental Amateur-Built Aircraft

94

Figure A3. Revised amateur-built aircraft fatal accident rate following NTSB accident data 

validation, 2001–2010.
NTSB The Safety of Experimental Amateur-Built Aircraft

95

Appendix B: E-AB Aircraft Accident 

Supplementary Data Form
NTSB The Safety of Experimental Amateur-Built Aircraft

96
NTSB The Safety of Experimental Amateur-Built Aircraft

97
NTSB The Safety of Experimental Amateur-Built Aircraft

98
NTSB The Safety of Experimental Amateur-Built Aircraft

99
NTSB The Safety of Experimental Amateur-Built Aircraft

100
NTSB The Safety of Experimental Amateur-Built Aircraft

101
NTSB The Safety of Experimental Amateur-Built Aircraft

102

Appendix C: Expanded Analysis of Amateur-Built 

Aircraft Accident Data, Calendar Year 2011

Most of the 227 E-AB aircraft involved in the 224 accidents investigated during 2011 

were airplanes. Figure C1 shows the types of aircraft involved in accidents during 2011.

Figure C1. Types of E-AB accident aircraft built by owners and bought as used, 2011.

E-AB Aircraft Makes

Figure C2 shows the manner in which the accident E-AB aircraft were built for those 

bought used and those built by their owners. The majority of accident aircraft, whether built by 

the owner or bought used, were built from kits, fewer were built from plans, and only three were 

built from original designs. Figure C3 shows the principal ―makes‖ of E-AB aircraft built by 

their owners, and Figure C4 shows the principal ―makes‖ of E-AB aircraft bought used. A large 

variety of aircraft kits and published plans are represented in both groups of aircraft. Kit 

manufacturers Van‘s Aircraft Company, Zenith Aircraft Company, Lancair, Kitfox Aircraft, and 

Rans Aircraft accounted for significant numbers of aircraft in both groups. The E-AB aircraft

make is identified for each accident aircraft in appendix F.
NTSB The Safety of Experimental Amateur-Built Aircraft

103

Figure C2. Type of E-AB aircraft building project for aircraft built by owners and those bought 

used.
NTSB The Safety of Experimental Amateur-Built Aircraft

104

Figure C3. E-AB accident aircraft makes built by owners.

23

12

6

4

3

3

51

0 10 20 30 40 50 60

Van's Aircraft

Zenith Aircraft Company

Lancair

Kitfox Aircraft

Glasair Aviation

Murphy Aircraft

All Other Makes

Accident Aircraft

Make (Kit Manufacturer)

Makes of Accident Aircraft Built by Owner, 2011
NTSB The Safety of Experimental Amateur-Built Aircraft

105

Figure C4. E-AB accident aircraft makes bought used.

17

8

7

6

6

4

4

4

4

3

62

0 10 20 30 40 50 60 70

Van's Aircraft

Lancair

Rans Designs

Avid Aircraft

Kitfox Aircraft

Aviat Aircraft

Glasair Aviation

Original Design

Sonex Aircraft

Zenith Aircraft Company

All Other Makes

Accident Aircraft Bought Used

Makes (Kit Manufacturer) of Accident Aircraft

Makes of Accident E-AB Aircraft Bought Used
NTSB The Safety of Experimental Amateur-Built Aircraft

106

Figure C5 shows the number of previous owners of these aircraft. Less than 50 percent

had had only one previous owner, and more than 20 percent had been bought and sold more than 

four times since they were built.

Figure C5. Number of previous owners for accident E-AB aircraft bought used.

54

31

12 11

7

10

0

10

20

30

40

50

60

1 2 3 4 5 6 or more

Accident Aircraft

Number of Previous Owners

Number of Previous Owners for Accident E-AB 

Aircraft Bought Used, 2011 
NTSB The Safety of Experimental Amateur-Built Aircraft

107

Appendix D: Amateur-Built Aircraft Survey

1.How many years have you been a certificated pilot? (enter whole numbers) 

2.What is the highest certificate you hold? 

o Student

o Sport

o Recreational

o Private

o Commercial

o Airline Transport (ATP)

3.What ratings or other certificates do you hold? [Mark all that apply]

Single-engine Land

Single-engine Sea

Multi-engine Land

Multi-engine Sea

Instrument

Rotorcraft (helicopter/gyroplane)

Lighter than air 

Flight Instructor (CFI, CFII, MEI)

Mechanic (A&P)

Repairman

Other (please specify) 

4. What additional endorsements have you obtained? [Mark all that apply]

High performance

Complex

Tail wheel

High altitude

None – or Not applicable

Other (please specify) 

YOUR CURRENT AMATEUR-BUILT AIRCRAFT
NTSB The Safety of Experimental Amateur-Built Aircraft

108

If you do not currently own or own multiple amateur-built aircraft please answer the 

remainder of the survey questions using your most recently owned or purchased amateur-built 

aircraft.

5. How many hours have you logged as Pilot in Command (PIC) over the following time periods 

for both all aircraft and your current amateur-built aircraft (E-AB)?

TotalHrsLast YearLast 90 days

All Aircraft

Current E-AB Aircraft

6. Approximately how many landings have you made in the last 90 days? 

All Aircraft

Current E-AB Aircraft

7. What type of amateur-built aircraft do you currently own? 

Make

Model

Year Certified

8. Your amateur-built aircraft is a:

o Airplane

o Glider

o Helicopter

o Gyrocopter

o Lighter than Air

o Weight-Shift

o Power Parachute

The following questions are intended to provide more detail about your current amateur-built 

aircraft. 

9. Which of the following best describes your current amateur-built aircraft? 

o Standard Factory kit 

o Quick Build kit

o Plans built

o Original Design 

o Other (please specify) 
NTSB The Safety of Experimental Amateur-Built Aircraft

109

10. How many total hours on the airframe and engine? (enter whole number)

Airframe

Engine

11. What year was the airworthiness certificate issued?

12. What type of engine is in your current amateur-built aircraft? 

o Traditional Aircraft engine (including non-certified variants) 

o Other Production-type four-stroke aircraft engine (Jabiru, Rotax 912, etc.) 

o Production-type two-stroke aircraft engine (Rotax 582, 2SI, etc.)

o Volkswagen 

o Subaru

o Honda

o Ford

o Corvair

o GM (other than Corvair) 

o GEO

o Suzuki

o Other 

o Two-stroke conversion

o Not Applicable

o Other (please specify):

13. What is the specific make, model and horsepower of your engine?

Make

Model

Horsepower

14. Was your engine ...

o New 

o Used (not overhauled) 

o Overhauled by an A&P 

o Overhauled by a non-A&P 

o Other (specify) 
NTSB The Safety of Experimental Amateur-Built Aircraft

110

15. What was the extent of the overhaul?

o Complete

o Top only

16. What is the specific make and model of your propeller?

Make

Model

17. Your propeller is...

o Wood

o Metal

o Composite

18. Your propeller is...

o Fixed

o Ground Adjustable

o Constant Speed

19. What type of instruments/avionics in your aircraft?

o Conventional primary flight instruments

o Glass cockpit primary flight display

20. What type of landing gear configuration does your aircraft have?

o Tricycle

o Tail wheel

o Floats

o Amphibian

o Other (specify)

21. Your landing gear is ...

o Fixed

o Retractable

22. What is the wing span, wing area and max gross weight of your amateur- built aircraft?

Wing Span (ft)

Wing Area (sq. ft)

Max Gross Weight (lbs)
NTSB The Safety of Experimental Amateur-Built Aircraft

111

23. What are the stall and max speeds (in knots) of your amateur-built aircraft? 

VS

VSO

VA

VNE

24. Is your aircraft approved for aerobatics?

o Yes

o No

25. Any restrictions (please specify)

26. Do you conduct aerobatics in your aircraft?

o Yes

o No

27. What is the number of seats in your current amateur-built aircraft?

o 1

o 2

o 3

o 4

o 5 or more

28. What type of restraints are installed in your aircraft?

o Lap Belt only

o 3 point shoulder harness

o 4 point harness

o 5 point harness

o Other (please specify)

29. What other safety related equipment is installed in your current amateur-built aircraft?

o Airbag

o Ballistic parachute

o Other (please specify)
NTSB The Safety of Experimental Amateur-Built Aircraft

112

30. Did you do an introductory or demo flight of your current model of amateur-built aircraft 

before obtaining one? 

o Yes

o No

31. Who provided the introductory or demo flight? 

o Kit manufacturer

o Private Owner

o Other (please specify)

32. Did you receive flight training for your current amateur-built aircraft before your first flight 

as pilot in command of your aircraft? 

o Yes

o No

33. Who conducted the training? 

o Kit Manufacturer

o Private Owner of same type of aircraft

o Private Owner of similar type of aircraft

o Private Owner of different type of aircraft

o CFI

o Other (please specify)

34. Did you receive flight training for your current amateur-built aircraft after your first flight as 

pilot in command of your aircraft? 

o Yes

o No

35. Who conducted the training? 

o Kit Manufacturer

o Owner of same type of aircraft

o Owner of similar type of aircraft

o Private Owner of different type of aircraft

o CFI

o Other (please specify)
NTSB The Safety of Experimental Amateur-Built Aircraft

113

36. Did your insurance company require any special transition training to insure your current 

amateur-built aircraft? 

o Yes

o No

o N/A-Self insured

37. How many hours of training did the insurance company require? How many did you 

complete?

Required Completed

Hours of dual instruction 

Hours of solo instruction

38. Did you build your current amateur-built aircraft? 

o Yes

o No (skip to Q55)

39. Did you completely build the aircraft or purchase it as a completed aircraft or a partially 

completed project?

o Built myself

o Purchased partially completed project

o Purchased completed aircraft

40. Why did you choose to build rather than purchase a completed aircraft (other than for 

educational or recreational purposes)? 

o To save money 

o Performance advantages

o Other (please specify) 

The following questions are about your building experience

41. Why did you choose to build rather than purchase a completed aircraft (other than for 

educational or recreational purposes)? 

To save money 

Performance advantages

Other (please specify) 
NTSB The Safety of Experimental Amateur-Built Aircraft

114

42. How long did it take you to complete your current amateur-built aircraft? 

Years

Months

Total Hours

43. How many aircraft (including your current amateur-built aircraft) have you built? 

44. Do you have a repairman certificate for your current amateur-built aircraft? 

o Yes

o No

45. Where was your aircraft built? (check all that apply)

Kit manufacturer onsite factory assist

Commercial aircraft service facility

Hangar

Owner‘s home

46. Did you receive technical assistance from any of the following during the building of your 

aircraft? (check all that apply)

EAA Technical Counselor

Kit Manufacturer

A & P

Other Builder(s)

47. How many inspections by others were performed during the build? (Enter 0 if none)

48. Who were the inspections performed by? (check all that apply)

EAA Technical Counselor

FAA inspector

A&P

Other builders
NTSB The Safety of Experimental Amateur-Built Aircraft

115

49. What type (if any) of training or experience in aircraft building techniques did you receive 

before or during your building process?

Assisted on another aircraft build

Attended kit manufacturer workshop

Attended EAA SportAir workshop

Attended workshops at AirVenture or other events

Other

The following questions are about your flight test and airworthiness certification process

50. The airworthiness certificate was issued by

o FAA

o DAR

51. Who performed the first test flight?

o Builder

o Hired flight test pilot

o Other (please specify)

52. How many Phase 1 test hours were required and completed?

Required

Completed

53. How detailed would you say was your flight test plan?

o Very Detailed

o Somewhat Detailed

o Somewhat Informal

54. What sources (if any) did you use in the development of your flight test plan?

Self-Developed only

EAA Flight Advisor

EAA Sport Air Flight testing Course

FAA Test flight Advisory Circular AC-90-89A

Kit Manufacturer training program

First Flight Video

Type Club/Owners Group

Other
NTSB The Safety of Experimental Amateur-Built Aircraft

116

55. Has your current amateur-built aircraft been modified from the original design 

specifications? 

o Yes

o No

o Don't Know

56. In which areas has your current amateur-built aircraft been modified? [Mark all that apply]

Fuel Systems

Airframe Design

Canopy/Door Mechanisms

Safety Harness

Control Systems

Powerplant

Other (please specify) 

57. Who made the modifications? (If owner/builder holds a current A&P certificate select FAA 

certified mechanic)

Builder

Owner 

Other Than

Builder

FAA 

Certified 

Mechanic

Don't 

Know Other NA

Fuel Systems o o o o o o

Airframe Design o o o o o o

Canopy/Door Mechanisms o o o o o o

Safety Harness o o o o o o

Control System o o o o o o

Powerplant o o o o o o

Other o o o o o o
NTSB The Safety of Experimental Amateur-Built Aircraft

117

58. Why were the modifications made? 

59. After the modifications were completed did you conduct any formal test flight(s)?

o Yes

o No

60. Have you received or found service instructions or bulletins related to the airframe since the 

purchase of your kit/plans?

o Yes

o No

61. Have they been completed?

o Yes

o No

62. How did you hear about them?

From FAA.Gov web site

From kit producer

Owners Forum/website

Type Club 

General Aviation Press (e.g. Aero-News, AV-Web, etc.)

Other

63. Have you received or found service instructions or bulletins related to the powerplant or 

propeller since they were purchased? 

Correct 

Deficiency

Improve 

Handling

Improve 

Performance

Other 

Reason NA

Fuel Systems o o o o o

Airframe Design o o o o o

Canopy/Door Mechanisms o o o o o

Safety Harness o o o o o

Control Systems o o o o o

Powerplant o o o o o

Other o o o o o
NTSB The Safety of Experimental Amateur-Built Aircraft

118

o Yes

o No

64. Have they been completed?

o Yes

o No

65. How did you hear about them?

From FAA.Gov web site

From kit producer

Owners Forum/website

Type Club 

General Aviation Press (e.g. Aero-News, AV-Web, etc.)

Other

The following questions are for analysis purposes only. They represent information that might 

provide insight into some of the answers to the questions on the survey.

66. What is your age? 

67. What is your approximate annual household income? 

o Less than $50,000

o Between $50,000 and $75,000

o Between $75,000 and $100,000

o Between $100,000 and $150,000

o Between $150,000 and $200,000

o $200,000 or more

68. Please indicate your highest level of education.

o High School or less

o Vocational/Technical

o College

o Graduate/Professional School
NTSB The Safety of Experimental Amateur-Built Aircraft

119

69. Please select the category that most closely describes your occupation.

o Professional/Technical

o Sales/Service

o Craftsman/Hourly Employee

o Self Employed Prof/Tech

o Self Employed Sales/Marketing

o Self Employed Craftsman

o Self Employed Other

o Admin/Managerial

o Clerical/Office

o Not Employed

o Military

o Student

o Retired
NTSB The Safety of Experimental Amateur-Built Aircraft

120

Appendix E: Expanded Results of Experimental 

Aircraft Association Survey of E-AB Aircraft 

Owners and Builders.

Figure E1 shows the breakdown of kit-built aircraft by manufacturer. Kits manufactured 

by Vans Aircraft Company accounted for 43 percent of these aircraft, with other manufacturers 

accounting for much smaller proportions of respondents‘ aircraft.

Figure E1. Kit manufacturers reported by survey respondents.

1638

247

235

225

136

125

120

76

52

45

34

31

29

27

24

23

598

0 200 400 600 800 1000 1200 1400 1600 1800

Van's Aircraft

Lancair

Glasair Aviation

Zenith Aircraft Company

Kitfox Aircraft

Sonex Aircraft

Rans Designs

Quad City Aircraft

Velocity Aircraft

Avid Aircraft

Wag-Aero Group

Kolb Aircraft

Murphy Aircraft

Pulsar Aircraft

RotorWay International

Bede Corp

All Other Kits

Number of Respondents

Kit Manufacturers Reported by Survey 

Respondents
NTSB The Safety of Experimental Amateur-Built Aircraft

121

Figure E2 shows the specific models of the aircraft kits produced by the four leading kit 

manufacturers reported by the survey respondents.

Figure E2. Kit models for the Van's, Lancair, Glasair, and Zenith aircraft kits reported in the 

survey.

Twenty-three percent of respondents reported aircraft that were built according to 

published plans, rather than assembled from manufactured kits. Respondents reported 140 

18

181

246

225

136

200

258

51

24

177

91

30

110

27

42

58

4

36

58

27

114

144

81

0 50 100 150 200 250 300

Van's RV-3

Van's RV-4

Van's RV-6

Van's RV-6A

Van's RV-7

Van's RV-7A

Van's RV-8

Van's RV-8A

Van's RV-9

Van's RV-9A

Van's RV-10

Van's RV-12

Lancair 200/235/320/360

Lancair ES

Lancair Legacy

Lancair IV/IV-P

Lancair Evolution

Glasair I

Glasair II

Glasair III

GlaStar

Zenith Zodiac CH601/650

Zenith STOL CH701/750/801

Number of Respondents

Frequency of Kit Models for Respondents 

Reporting Van's, Lancair, Glasair, and Zenith 

Aircraft Kits
NTSB The Safety of Experimental Amateur-Built Aircraft

122

distinct published plans. The distribution of plans-built aircraft makes, or designs, is shown in

Figure E3.

-

Figure E3. Plans-built aircraft designs reported by survey respondents.

The largest of the plans-built aircraft makes is the Burt Rutan Long-EZ. A very large 

number of other published plans are also reflected in the survey responses. The original design 

category comprises 136 unique one-off designs described by a small subset of survey 

respondents.

Figure E4 shows the years taken to complete the E-AB aircraft project for the 

respondents who had finished building their aircraft. The median years to complete the aircraft 

was 4 years, but there was considerable variation. Figure E5 shows the total hours reported by 

these respondents to complete their E-AB aircraft. The median was 2,000 hours, but again, there 

was considerable variation.

107

69

59

53

53

43

40

40

33

32

31

29

26

26

25

46

0 20 40 60 80 100 120

Rutan Long-EZ

Cozy

Pitts Special

Rutan Varieze

Thorp

Steen Aero Lab

Starduster

Pietenpol

Wittman Tailwind

Monnett

Acro Sport

Bushby/Mustang Aeronautics

Bowers

Rand Robinson

Ace Aircraft

All Other Plans

Respondents Reporting Plans-Built Aircraft

Principal Plans-Built Aircraft Designs
NTSB The Safety of Experimental Amateur-Built Aircraft

123

Figure E4. Years to complete for the 3,095 respondents reporting this information.

576

959

1,286

1,533

1,799

2,307

2,447

103 158 219 267 320

469

578

19 31 36 40 45 61 70 0

500

1,000

1,500

2,000

2,500

3,000

<1 year <2 years <3 years <4 years <5 years <10 years <20 years

Cummulative Completed Aircraft

Completion Time

Completion Time by E-AB Aircraft Build Type

Kit-Built Plans-Built Original Design
NTSB The Safety of Experimental Amateur-Built Aircraft

124

Figure E5. Total build hours for the 1,648 respondents reporting this information.

95

296

764

1,162

1,294 1,337

1,390

14

32

95

162 192 210 230

8 9 17 22 22 25 28 0

200

400

600

800

1,000

1,200

1,400

1,600

<500 <1,000 <2,000 <3,000 <4,000 <5,000 <10,000

Cumulative Completed Aircraft

Building Hours

Cummulative Hours Expended by Respondents 

Building their E-AB Aircraft by Build Type

Kit-Built Plans-Built Original Design
NTSB The Safety of Experimental Amateur-Built Aircraft

125

Appendix F: Experimental Amateur-Built Study Cases, Calendar 

Year 2011

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

WPR11CA086 1/1/2011 Torrance, CA Nonfatal N322RV Airplane Vans RV4 Built Landing Abnormal 

Runway 

Contact

CEN11CA143 1/2/2011 Carlisle, AR Nonfatal N876KF Airplane Kitfox III Purchased Used Landing System/

Component 

Failure – NonPower

WPR11CA088 1/4/2011 Homedale, ID Nonfatal N90TY Airplane Kitfox IV Built Takeoff Abnormal 

Runway 

Contact

CEN11CA165 1/25/2011 Terlingua, TX Nonfatal N947RG Airplane Kitfox III Purchased Used Takeoff Loss of 

Control on 

Ground

WPR11CA110 1/26/2011 Toutle, WA Nonfatal N92LW Airplane Cuby Purchased Used Landing Abnormal 

Runway 

Contact

WPR11CA112 1/28/2011 Buckeye, AZ Nonfatal N8053R Airplane Rans S-6 Built En Route System/

Component 

Failure – NonPower

ANC11CA011 1/29/2011 Anchorage, AK Nonfatal N9015U Airplane Got Rocks Purchased Used Landing Loss of 

Control on 

Ground

CEN11CA166 1/29/2011 Wellington, CO Nonfatal N15XP Glider Rutan Solitaire Purchased Used Landing Undershoot/

Overshoot

CEN11LA168A 1/29/2011 Burlington, IA Nonfatal N200BE Airplane Zenith Aircraft Company 601XL Built Landing Runway 

Incursion -

Vehicle

CEN11LA168B 1/29/2011 Burlington, IA Nonfatal N602CB Airplane Model-1 Purchased Used Landing Runway 

Incursion -

Vehicle

ERA11CA153 1/30/2011 Crescent City, FL Nonfatal N324AL Airplane Arion Aircraft Lightning Purchased Used Landing Abnormal 

Runway 

Contact

WPR11CA130 2/9/2011 Wilsonville, OR Nonfatal N238MA Airplane Glastar Purchased Used Landing Abnormal 

Runway 

Contact
NTSB The Safety of Experimental Amateur-Built Aircraft

126

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

WPR11CA134 2/12/2011 Groveland, CA Nonfatal N17AJ Airplane Christen Eagle II Purchased Used Landing Loss of 

Control on 

Ground

ERA11LA142 2/13/2011 Dawsonville, GA Nonfatal N351E Airplane Lancair 320 Purchased Used Maneuvering Fuel Related

ERA11LA150 2/17/2011 Stetson, ME Nonfatal N213 Airplane Kolb MK III Purchased Used En Route System/

Component 

Failure –

Powerplant

WPR11FA147 2/26/2011 Milford, UT Fatal N989TT Airplane Lancair 360 Purchased Used En Route Unintended 

Flight in IMC

ERA11CA177 3/3/2011 Indian Trail, NC Nonfatal N788Q Airplane Kitfox IV Built Takeoff Abnormal 

Runway 

Contact

WPR11FA153 3/4/2011 Myrtle Creek, OR Nonfatal N4374K Airplane Kitfox IV-1200 Built Initial Climb Windshear/

Thunderstorm

WPR11FA155 3/7/2011 Newberry Springs, 

CA

Fatal N122B Airplane Rand Robinson KR-2 Purchased Used En Route System/

Component 

Failure – NonPower

WPR11FAMS1 3/11/2011 Unknown, AZ Fatal N650RV Airplane Vans RV6 Built Unknown Unknown

ERA11CA195 3/19/2011 Gainesville, FL Nonfatal N109BX Airplane Christen Eagle II Purchased Used Approach Loss of 

Control in 

Flight

ERA11LA197 3/19/2011 Lincoln, AL Nonfatal N192AB Helicopter Rotorway Exec Purchased Used En Route System/

Component 

Failure –

Powerplant

ERA11LA208 3/19/2011 Clinton, SC Fatal None Airplane JTD Mini-Max Built Takeoff Collision on 

Takeoff or 

Landing

WPR11CA171B 3/19/2011 Arlington, WA Nonfatal N11NL Airplane Rutan Long-EZ Built Standing Ground 

Collision

CEN11CA242 3/21/2011 Ferris, TX Nonfatal N1317L Airplane Aero Adventure Aventura Purchased Used Landing Loss of 

Control in 

Flight

ERA11LA213 3/25/2011 Calhoun, GA Nonfatal N770VP Airplane Volksplane VP-1 Built Initial Climb System/

Component 

Failure –

Powerplant

ERA11LA228 3/29/2011 Crescent City, FL Nonfatal N5842 Airplane Aero Adventure Aventura II Built Initial Climb Loss of 

Control in 

Flight
NTSB The Safety of Experimental Amateur-Built Aircraft

127

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

WPR11LA180 4/1/2011 Cedar City, UT Nonfatal N613HH Airplane Avid Flyer Purchased Used Initial Climb System/

Component 

Failure –

Powerplant

CEN11LA281 4/2/2011 Brookfield, MO Nonfatal N6313T Airplane Avid Mark IV Purchased Used Landing System/

Component 

Failure – NonPower

ERA11FA222 4/3/2011 Chesapeake, VA Fatal N164T Airplane Lancair 360 Purchased Used Initial Climb Fuel Related

WPR11LA187 4/5/2011 El Centro, CA Nonfatal N128CF Airplane Zenith Aircraft Company STOL 

CH701

Built Landing System/

Component 

Failure –

Powerplant

WPR11LA193 4/8/2011 Temple Bar, AZ Nonfatal N320BB Airplane Lancair 360 Purchased Used En Route System/

Component 

Failure –

Powerplant

WPR11LA205 4/10/2011 Ramona, CA Nonfatal N611JB Airplane Bushby/Mustang Aeronautics 

Midget Mustang

Purchased Used Initial Climb System/

Component 

Failure – NonPower

CEN11CA282 4/12/2011 Davenport, IA Nonfatal N701YB Airplane Zenith Aircraft Company STOL 

CH701

Built Takeoff System/Comp

onent Failure 

– Non-Power

WPR11LA199 4/14/2011 Winchester, CA Nonfatal N632DR Airplane Zenith Aircraft Company STOL 

CH750

Built En Route System/

Component 

Failure –

Powerplant

ERA11CA248 4/15/2011 Baltimore, MD Nonfatal N57CW Airplane Lancair 320 Built Landing Abnormal 

Runway 

Contact

WPR11LA202 4/16/2011 Marana, AZ Nonfatal N107JL Airplane Rans S-12 Purchased Used En Route System/

Component 

Failure –

Powerplant

CEN11FA299 4/17/2011 San Angelo, TX Fatal N38RC Airplane Christen Eagle II Purchased Used Maneuvering Low Altitude 

Operation

CEN11FA300 4/21/2011 Elk City, OK Fatal N7804C Airplane Wittman Tailwind W-8 Purchased Used Maneuvering Loss of 

Control in 

Flight

ERA11CA256 4/21/2011 Locust Grove, GA Nonfatal N190GE Airplane Vans RV8 Built Takeoff Loss of 

Control on 

Ground
NTSB The Safety of Experimental Amateur-Built Aircraft

128

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

CEN11LA305 4/23/2011 Massillon, OH Nonfatal N614S Helicopter Rotorway Exec Built En Route System/

Component 

Failure –

Powerplant

WPR11CA206 4/23/2011 Heber, UT Nonfatal N5491W Airplane Team Rocket F1 Built Landing Loss of 

Control on 

Ground

WPR11LA207 4/23/2011 Marsing, ID Nonfatal N59TD Airplane Vans RV7A Built Initial Climb System/

Component 

Failure –

Powerplant

CEN11CA321 4/27/2011 Minford, OH Nonfatal N718PF Airplane Vans RV10 Built En Route System/

Component 

Failure – NonPower

CEN11FA310 4/29/2011 Pulaski, WI Fatal N701MJ Airplane Zenith Aircraft Company STOL 

CH701

Built Initial Climb Loss of 

Control in 

Flight

ERA11CA279 4/30/2011 Somerset, PA Nonfatal N145HF Airplane Avid Flyer Purchased Used Initial Climb System/

Component 

Failure –

Powerplant

CEN11FA312 5/1/2011 Elephant Butte, NM Fatal N89MM Airplane Kitfox Speedster Purchased Used En Route Loss of 

Control in 

Flight

WPR11LA216 5/1/2011 Livermore, CA Nonfatal N998RV Airplane Vans RV8 Built Landing Abrupt 

Maneuver

CEN11CA314 5/2/2011 Kansas City, MO Nonfatal N50KP Airplane Lancair Legacy Built Landing Undershoot/

Overshoot

CEN11LA316 5/3/2011 Blue Springs, NE Fatal N103EB Gyroplane Rotor Flight Dynamics 

Dominator

Built Initial Climb Collision on 

Takeoff or 

Landing

CEN11FA319 5/4/2011 Shreveport, LA Fatal N914KM Airplane Europa XS Purchased Used En Route Loss of 

Control in 

Flight

ERA11LA282 5/4/2011 Palm Coast, FL Nonfatal N705AP Airplane D'Apuzzo Senior Aero Sport D260Purchased Used En Route System/

Component 

Failure –

Powerplant

CEN11CA326 5/5/2011 Albuquerque, NM Nonfatal N314JF Airplane Quickie Aircraft Quickie Q2 Purchased Used Maneuvering System/

Component 

Failure – NonPower

ERA11FA285 5/6/2011 Richlands, NC Fatal N23PH Airplane Lancair Legacy Built En Route Fuel Related
NTSB The Safety of Experimental Amateur-Built Aircraft

129

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

CEN11FA324 5/7/2011 Conroe, TX Fatal N913RA Airplane S.A.Ravin Aircraft 500 Built Initial Climb Fire – NonImpact

ERA11LA300 5/13/2011 Tidioute, PA Nonfatal N433UB Airplane Zenith Aircraft Company STOL 

CH701

Built Approach Other

CEN11CA336 5/14/2011 Scott, LA Nonfatal None Gyroplane KB3 Gyroplane Built Takeoff Collision on 

Takeoff or 

Landing

ERA11CA311 5/17/2011 Taccoa, GA Nonfatal N1150 Airplane Ace Aircraft Corben Junior Ace Purchased Used Landing Loss of 

Control on 

Ground

WPR11FA230 5/18/2011 Pioneer, CA Fatal N121J Airplane Lancair Legacy Purchased Used En Route Controlled 

Flight Info 

Terrain

CEN11CA354 5/21/2011 Albuqurque, NM Nonfatal N79BC Airplane Lancair 320 Purchased Used Landing Loss of 

Control on 

Ground

WPR11LA233 5/21/2011 Cody, WY Nonfatal N52VC Airplane Vans RV6A Purchased Used En Route Controlled 

Flight Info 

Terrain

CEN11FA346 5/22/2011 Erie, CO Fatal N420FH Airplane Cassutt III Built Initial Climb Other

CEN11LA361 5/22/2011 Colorado Springs, 

CO

Nonfatal N457CF Airplane Pitts S1S Purchased Used Landing Abnormal 

Runway 

Contact

WPR11LA234 5/24/2011 Puyallup, WA Nonfatal N34NH Airplane Zenith Aircraft Company STOL 

CH701

Built Landing Loss of 

Control in 

Flight

CEN11LA367 5/30/2011 Sioux City, IA Nonfatal N204TJ Airplane Cozy MK III Built Maneuvering System/

Component 

Failure –

Powerplant

ERA11LA325 6/3/2011 Merritt Island, FL Nonfatal N434JC Airplane Comp Air CA-4 Built Landing Abnormal 

Runway 

Contact

WPR11CA249 6/3/2011 Heron, MT Nonfatal N316BR Airplane Smith Aviation Super Cub Built Landing Abnormal 

Runway 

Contact

CEN11CA377 6/4/2011 Dexter, NM Nonfatal N820RC Airplane Vans RV6A Purchased Used Landing Collision on 

Takeoff or 

Landing

CEN11LA371 6/4/2011 Edgewood, NM Nonfatal N514R Airplane Vans RV9A Built Takeoff Runway 

Excursion
NTSB The Safety of Experimental Amateur-Built Aircraft

130

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

CEN11LA374 6/4/2011 Minneapolis, MN Nonfatal N242RM Airplane Progressive Aerodyne SeaRey Built Initial Climb System/

Component 

Failure – NonPower

WPR11CA247 6/4/2011 Bellingham, WA Nonfatal N118PS Airplane Nieuport 11 Purchased Used Landing Loss of 

Control on 

Ground

CEN11CA410 6/6/2011 Canon City, CO Nonfatal N238W Airplane Glasair Glastar Built Approach System/

Component 

Failure –

Powerplant

CEN11CA389 6/10/2011 Oakwood, OK Nonfatal N25LC Airplane Vans RV6A Built Landing Collision on 

Takeoff or 

Landing

ERA11LA336 6/10/2011 Scarborough, ME Nonfatal N915PK Airplane Kitfox II Purchased Used Initial Climb Loss of 

Control in 

Flight

CEN11LA384 6/12/2011 Azle, TX Nonfatal N6ZY Airplane Lancair 360 Built En Route System/

Component 

Failure –

Powerplant

ERA11CA339 6/12/2011 Bennettsville, SC Nonfatal N444YB Airplane Rans S-10 Purchased Used Takeoff Runway 

Excursion

WPR11FA258 6/12/2011 Aguila, AZ Nonfatal N189SB Airplane Murphy Moose Built Maneuvering System/

Component 

Failure –

Powerplant

CEN11CA395 6/13/2011 Moriarity, NM Nonfatal N81DN Airplane Rutan Long-EZ Purchased Used Landing Loss of 

Control on 

Ground

CEN11LA385 6/13/2011 Coalgate, OK Nonfatal N80WW Airplane Vans RV6A Built En Route System/

Component 

Failure –

Powerplant

CEN11CA411 6/18/2011 Gardner, KS Nonfatal N563 Airplane Sonex Purchased Used Approach Undershoot/

Overshoot

WPR11FA268 6/19/2011 Tehachapi, CA Fatal N851LT Airplane Thorp T-18 Purchased Used En Route Controlled 

Flight Info 

Terrain

ERA11CA355 6/20/2011 Carthage, NC Nonfatal N4209F Airplane CGS Aviation Hawk Arrow Purchased Used Approach System/

Component 

Failure –

Powerplant
NTSB The Safety of Experimental Amateur-Built Aircraft

131

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

WPR11LA280 6/22/2011 Sheridan, WY Nonfatal N4546Y Airplane Vans RV8 Built Landing Loss of 

Control on 

Ground

CEN11CA423 6/24/2011 Angel Fire, NM Nonfatal N678VR Airplane Vans RV8 Purchased Used Landing Loss of 

Control on 

Ground

CEN11LA419 6/25/2011 Gwinn, MI Nonfatal N16DV Airplane Pietenpol Air Camper Built Landing Loss of 

Control on 

Ground

ERA11FA360 6/26/2011 Andalusia, AL Fatal N289DH Airplane Barracuda Built Approach Loss of 

Control in 

Flight

ERA11LA361B 6/26/2011 Pompano Beach, FL Nonfatal N484BD Airplane Cozy MK IV Built Taxi Ground 

Collision

WPR11LA289 6/26/2011 West Glacier, MT Nonfatal N397JL Airplane Fly Fisher Purchased Used Initial Climb System/

Component 

Failure –

Powerplant

WPR11LA291 6/27/2011 Moses Lake, WA Nonfatal N9103L Airplane Quad City Ultralight Challenger 

II

Purchased Used Maneuvering System/

Component 

Failure –

Powerplant

CEN11LA432 6/28/2011 Gladewater, TX Nonfatal N751WB Airplane Zenith Aircraft Company 

CH750

Built Takeoff Loss of 

Control in 

Flight

CEN11FA431 6/29/2011 Howell, MI Fatal N8AL Airplane Thorp T-18 Purchased Used Approach Loss of 

Control in 

Flight

CEN11FA433 6/29/2011 Neshkoro, WI Fatal N12911 Airplane Quad City Ultralight Challenger 

II

Built Initial Climb System/

Component 

Failure –

Powerplant

CEN11LA429 6/29/2011 Oshkosh, WI Nonfatal N56PK Airplane Wittman Tailwind W-8 Built Initial Climb System/

Component 

Failure –

Powerplant

CEN11CA439 6/30/2011 Sisterdale, TX Nonfatal N6917 Airplane B-2 Purchased Used Maneuvering Controlled 

Flight Info 

Terrain

CEN11FA434 6/30/2011 Yukon, OK Fatal N358MA Airplane Lancair 320 Purchased Used Approach Loss of 

Control in 

Flight
NTSB The Safety of Experimental Amateur-Built Aircraft

132

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

CEN11FA436 6/30/2011 Ottumwa, IA Fatal N773RY Airplane 773 Racer Built En Route System/

Component 

Failure –

Powerplant

CEN11LA449 6/30/2011 Leander, TX Nonfatal N59VA Airplane Vans RV9A Purchased Used Landing System/

Component 

Failure –

Powerplant

ERA11CA373 6/30/2011 Gray Coourt, SC Nonfatal N67KL Airplane Zenith Aircraft Company 

CH601

Built En Route System/

Component 

Failure –

Powerplant

CEN11LA455 7/1/2011 Toledo, OH Nonfatal N433GC Airplane Rans S-17 Purchased Used Initial Climb Loss of 

Control in 

Flight

ERA11FA374 7/2/2011 Calhoun, GA Fatal N6PX Airplane Sonex Purchased Used Initial Climb System/

Component 

Failure –

Powerplant

CEN11FA443 7/3/2011 Port O'Connor, TX Fatal N11001 Airplane Lancair IV P Built En Route Loss of 

Control in 

Flight

ERA11LA400 7/4/2011 Fort Drum, FL Nonfatal N3226N Airplane Vans RV4 Purchased Used Initial Climb System/

Component 

Failure –

Powerplant

CEN11CA454 7/6/2011 Decker, IN Nonfatal N25VK Gyroplane Rotary Air Force RAF 2000 Purchased Used Landing Abnormal 

Runway 

Contact

ANC11LA060 7/7/2011 Sterling, AK Nonfatal N18YX Airplane Sonex Waiex Purchased Used Initial Climb System/

Component 

Failure –

Powerplant

CEN11LA464 7/7/2011 East Liverpool, OH Nonfatal N7808M Airplane DerJager D 1X Purchased Used Approach Loss of 

Control in 

Flight

CEN11FA469 7/9/2011 Dudley, MO Fatal N113RB Airplane Monnett Sonerai II Built Unknown Loss of 

Control in 

Flight

WPR11CA321 7/10/2011 Cedar City, UT Nonfatal N2015U Airplane Thorp T-221 Purchased used En Route Fuel Related

CEN11LA490 7/13/2011 Peyton, CO Nonfatal N61262 Airplane Darrow AL-6 Purchased Used En Route System/

Component 

Failure –

Powerplant
NTSB The Safety of Experimental Amateur-Built Aircraft

133

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

CEN11LA481 7/15/2011 Jackson, MI Nonfatal N122DG Gyroplane Rhino II Built Takeoff Loss of 

Control in 

Flight

ERA11LA403 7/15/2011 Batavia, NY Nonfatal N113SM Airplane Murphy Rebel Elite Purchased Used Initial Climb Loss of 

Control in 

Flight

CEN11CA486 7/16/2011 Paxton, IL Nonfatal N9040W Airplane Zenith Aircraft Company STOL 

CH701

Purchased Used Takeoff Loss of 

Control in 

Flight

CEN11LA488 7/16/2011 Jackson, MI Nonfatal N341MD Airplane Volksplane VP-1 Built Initial Climb System/

Component 

Failure –

Powerplant

WPR11FA333 7/17/2011 Glendale, OR Fatal N701RD Airplane Zenith Aircraft Company STOL 

CH701

Purchased Used Takeoff System/

Component 

Failure –

Powerplant

WPR11CA341 7/19/2011 SAN JOSE, CA Nonfatal N411TM Airplane Starduster Starduster Too SA300Purchased Used Landing Ground 

Collision

CEN11CA521 7/20/2011 Jamestown, ND Nonfatal N343A Airplane Glasair II Built Landing Loss of 

Control on 

Ground

CEN11LA527 7/22/2011 Ashtabula, OH Nonfatal N240JS Airplane Quickie Aircraft Quickie Q2 Built Takeoff System/

Component 

Failure –

Powerplant

ERA11LA418 7/24/2011 Hartford, KY Nonfatal N164BF Airplane Vans RV6 Built En Route Fuel Related

CEN11LA506 7/25/2011 Oshkosh, WI Nonfatal N559RD Gyroplane Rotor Flight Dynamics 

Dominator

Purchased Used Takeoff Loss of 

Control in 

Flight

CEN11LA514 7/25/2011 Monroe City, MO Nonfatal N20JE Airplane Vans RV4 Purchased Used Approach System/

Component 

Failure –

Powerplant

WPR11LA364 7/26/2011 Sedona, AZ Nonfatal N671T Airplane Express Aircraft Company 

Series 2000

Built Landing Abnormal 

Runway 

Contact

CEN11LA530 7/28/2011 Fort Worth, TX Nonfatal N114DC Airplane Vans RV4 Purchased Used En Route Fuel Related

CEN11LA539 7/29/2011 Salem, IA Nonfatal N115RH Airplane Cavalier SA102.5 Purchased Used Maneuvering System/

Component 

Failure –

Powerplant
NTSB The Safety of Experimental Amateur-Built Aircraft

134

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

WPR11CA353 7/29/2011 Sheridan, WY Nonfatal N742RJ Airplane Vans RV7A Built Takeoff Loss of 

Control in 

Flight

CEN11FA528 7/30/2011 Springfield, OH Fatal N453WB Airplane Wright B Flyer Built En Route System/

Component 

Failure –

Powerplant

ERA11CA432 7/30/2011 Huntington, WV Nonfatal N434WM Airplane Rans S-6S Purchased Used Takeoff Abnormal 

Runway 

Contact

CEN11FA537 7/31/2011 Big Rock, IL Fatal N345JM Airplane E-Racer Built Maneuvering Loss of 

Control in 

Flight

WPR11CA358 7/31/2011 Yamhill, OR Nonfatal N30456 Airplane Avid Mark IV Built Landing System/

Component 

Failure – NonPower

WPR11LA371 8/2/2011 Republic, WA Nonfatal N3135J Airplane Kolb Twinstar II Built Landing Loss of 

Control on 

Ground

CEN11LA546 8/4/2011 Reedsburg, WI Fatal N340BR Airplane Quad City Ultralight Challenger 

II

Built Takeoff Loss of 

Control in 

Flight

CEN11CA550 8/5/2011 Colorado Springs, 

CO

Nonfatal N675RE Airplane Vans RV6A Purchased Used Landing Abnormal 

Runway 

Contact

ERA11CA440 8/5/2011 Frostproof, FL Nonfatal N13LN Airplane Arion Aircraft Lightning Built Initial Climb Loss of 

Control in 

Flight

CEN11LA553 8/6/2011 Metone, IN Nonfatal N128BH Helicopter Eagle R&D Helicycle Built Landing System/

Component 

Failure –

Powerplant

ERA11CA442 8/6/2011 Farmingdale, NY Nonfatal N723AD Airplane Arion Aircraft Lightning Built Landing Loss of 

Control on 

Ground

WPR11LA373 8/6/2011 Chino Hills, CA Nonfatal N162CT Helicopter Rotorway Exec Built En Route System/

Component 

Failure –

Powerplant

ERA11LA444 8/7/2011 Paducah, KY Nonfatal N462WP Airplane Vans RV7A Built Initial Climb System/

Component 

Failure –

Powerplant
NTSB The Safety of Experimental Amateur-Built Aircraft

135

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

WPR11CA399 8/12/2011 Dubois, WY Nonfatal N56WY Airplane CubCrafters Carbon Cub Purchased Used En Route Controlled 

Flight Info 

Terrain

CEN11LA573A 8/13/2011 Conroe, TX Fatal N16DD Airplane Vans RV8 Built Maneuvering Midair 

Collision

CEN11LA573B 8/13/2011 Conroe, TX Fatal N189DK Airplane Vans RV6 Built Maneuvering Midair 

Collision

CEN11LA671 8/13/2011 Lake Jackson, TX Nonfatal N7167S Airplane Fisher Flying Products Horizon 

2

Purchased Used Takeoff System/

Component 

Failure –

Powerplant

CEN11LA672 8/13/2011 Bryan, TX Nonfatal N53QB Airplane Slip Stream International 

Genesis

Purchased Used Initial Climb Loss of 

Control in 

Flight

ERA11CA455 8/13/2011 Abingdon, VA Nonfatal N376CG Airplane Just Aircraft Highlander Built Takeoff Runway 

Excursion

CEN11LA596 8/17/2011 Columbia, IL Nonfatal N284E Airplane Jabiru SP170 Purchased Used Landing System/

Component 

Failure – NonPower

ERA11FA463 8/17/2011 Ransom Township, 

PA

Fatal N6613Z Airplane Quad City Ultralight Challenger 

II

Purchased Used Maneuvering Controlled 

Flight Info 

Terrain

ERA11LA459 8/17/2011 Maysville, NC Nonfatal N523RE Airplane Pegazair STOL 100 Built Initial Climb Loss of 

Control in 

Flight

WPR11FA392 8/18/2011 Moore, ID Fatal N559Y Glider Briegleb BG-12B Purchased Used Landing Loss of 

Control in 

Flight

WPR11LA405 8/18/2011 Snohomish, WA Nonfatal N701BZ Airplane Zenith Aircraft Company STOL 

CH701

Built Landing Abnormal 

Runway 

Contact

CEN11LA591 8/20/2011 Delaware, OH Nonfatal N2631B Gyroplane American Autogyro Sparrow 

Hawk

Purchased Used Initial Climb Abnormal 

Runway 

Contact

ERA11CA477 8/20/2011 Bessemer, AL Nonfatal N2997G Airplane Pitts S1C Purchased Used Landing Loss of 

Control on 

Ground

ERA11CA478 8/20/2011 Smithville, TN Nonfatal N52CH Airplane Avid Mark IV Purchased Used Takeoff Loss of 

Control on 

Ground

ERA11FA468A 8/20/2011 Hammonton, NJ Fatal N71DM Airplane Lancair IV-P Built Maneuvering Midair 

Collision
NTSB The Safety of Experimental Amateur-Built Aircraft

136

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

CEN11LA588 8/21/2011 La Porte City, IA Nonfatal N540AF Airplane Murphy Rebel Elite Built Maneuvering System/

Component 

Failure – NonPower

ERA11CA471 8/24/2011 Ocala, FL Nonfatal N250CH Airplane Glasair I TD Purchased Used Landing System/

Component 

Failure – NonPower

CEN11FA597 8/25/2011 Heath, OH Fatal N777BN Airplane Lancair 235 Purchased Used Takeoff Loss of 

Control on 

Ground

WPR11LA436 8/25/2011 Mile Hi Landing 

Strip, ID

Nonfatal N727WW Airplane Performance Air PA-18 Purchased Used Landing Abnormal 

Runway 

Contact

ERA11LA473 8/26/2011 Carlton, NY Nonfatal N246CV Airplane Zenith Aircraft Company STOL 

CH701

Built Maneuvering Fuel Related

WPR11LA412 8/28/2011 Albany, OR Nonfatal N642DW Airplane Vans RV6A Built En Route System/

Component 

Failure –

Powerplant

CEN11LA618 9/2/2011 Marion, IL Nonfatal N100VY Airplane Sonex Waiex Built Initial Climb System/

Component 

Failure –

Powerplant

ERA11LA483 9/3/2011 Hollywood, FL Nonfatal N241BD Airplane Vans RV6A Purchased Used Takeoff System/

Component 

Failure –

Powerplant

WPR11CA433 9/3/2011 Kanab, UT Nonfatal N17S Airplane Glasair III Purchased Used Landing System/

Component 

Failure – NonPower

CEN11FA616 9/4/2011 Seward, NE Fatal N88CE Airplane Christen Eagle II Purchased Used Initial Climb System/

Component 

Failure –

Powerplant

ERA11CA482 9/4/2011 Memphis, TN Nonfatal N36V Airplane Questair Venture Built Landing System/

Component 

Failure – NonPower

WPR11FA428 9/4/2011 Caldwell, ID Fatal N624JS Airplane Kitfox Series 7 Built Initial Climb Loss of 

Control in 

Flight

WPR11FA429 9/4/2011 Kanab, UT Fatal N9DZ Airplane Rutan Long-EZ Built En Route Unknown
NTSB The Safety of Experimental Amateur-Built Aircraft

137

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

ERA11CA485 9/5/2011 Beaufort, NC Nonfatal N334JH Airplane Glasair SHA Built Initial Climb Fuel Related

CEN11FA634 9/7/2011 Winfield, KS Fatal N554JR Airplane Vans RV7A Built Unknown Loss of 

Control in 

Flight

ERA11CA487 9/10/2011 Panama City, FL Nonfatal N407HK Airplane Thorp T-18 Built Landing Collision on 

Takeoff or 

Landing

WPR11LA451 9/12/2011 Lancaster, CA Nonfatal N2WL Airplane White Lightning WLAC-1 Purchased Used Approach System/

Component 

Failure –

Powerplant

WPR11FA450 9/15/2011 West Jordan, UT Fatal N641JC Airplane Vans RV6A Purchased Used Approach Loss of 

Control in 

Flight

WPR11FA453 9/15/2011 Reno, NV Nonfatal N521XD Airplane Questair Venture Built Initial Climb System/

Component 

Failure –

Powerplant

CEN11LA658 9/18/2011 Lancaster, TX Nonfatal N98D Airplane Vans RV8 Built Landing System/

Component 

Failure – NonPower

CEN11FA652 9/19/2011 Socorro, NM Fatal N91TX Airplane New Century Aerosport Radial 

Rocket

Purchased Used Maneuvering Loss of 

Control in 

Flight

ERA11LA519 9/19/2011 Okeechobee, FL Nonfatal N79GH Airplane Bakeng Deuce Purchased Used Landing Abnormal 

Runway 

Contact

WPR11LA459 9/19/2011 Greenleaf, ID Nonfatal N77VW Airplane Steen Aero Lab Skybolt Purchased Used Maneuvering System/

Component 

Failure – NonPower

WPR11LA461 9/22/2011 Wells, NV Nonfatal N49S Airplane Breezy RLU-1 Purchased Used Maneuvering Controlled 

Flight Info 

Terrain

CEN11CA665 9/23/2011 Lyons, WI Nonfatal N6YC Airplane Vans RV6 Purchased Used Landing Abnormal 

Runway 

Contact

CEN11FA663 9/23/2011 Plainwell, MI Fatal N54WB Airplane Thorp T-18 Built Approach Collision on 

Takeoff or 

Landing

CEN11CA667 9/24/2011 Lemars, IA Nonfatal N29RT Airplane Tandem Rocket Built Maneuvering Loss of 

Control in 

Flight
NTSB The Safety of Experimental Amateur-Built Aircraft

138

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

CEN11LA415 9/24/2011 Lafayette, LA Nonfatal N211KF Airplane Kitfox IV Purchased Used Landing System/

Component 

Failure –

Powerplant

WPR11LA477A 9/24/2011 West Jordan, UT Nonfatal N23UT Airplane Starduster Starduster Too SA300Purchased Used Taxi Ground 

Collision

ERA11FA504 9/25/2011 Sanford, NC Fatal N360TV Airplane Velocity RG Purchased Used Initial Climb System/

Component 

Failure –

Powerplant

CEN11LA669 9/27/2011 Marietta, OH Nonfatal N499RV Airplane Vans RV10 Purchased Used En Route System/

Component 

Failure –

Powerplant

WPR11FA474 9/29/2011 Chualar, CA Fatal N42GP Airplane Zivko Aeronautics Edge 540 Purchased Used Maneuvering Low Altitude 

Operation

CEN11CA679 9/30/2011 Hays, KS Nonfatal N384JP Airplane Murphy Moose Built En Route System/

Component 

Failure – NonPower

ERA11FA512 9/30/2011 Falls of Rough, KY Fatal N43KH Airplane Glasair III Purchased Used Maneuvering System/

Component 

Failure –

Powerplant

CEN12CA003 10/1/2011 Riley, KS Nonfatal N2417T Airplane Rans S-7 Purchased Used Takeoff Fuel Related

CEN12CA005 10/2/2011 Brush, CO Nonfatal N287BM Airplane Bushby/Mustang Aeronautics 

Mustang II

Built Taxi Loss of 

Control on 

Ground

WPR12FA001 10/4/2011 West Jordan, UT Fatal N91BV Airplane Pulsar 582 Purchased Used Initial Climb Loss of 

Control in 

Flight

CEN12LA008 10/5/2011 Versailles, MO Nonfatal N9144E Airplane Kolb MK III Purchased Used Initial Climb System/

Component 

Failure –

Powerplant

ERA12FA006 10/5/2011 Hedgesville, WV Fatal N747HW Airplane Arion Aircraft Lightning Built Initial Climb Loss of 

Control in 

Flight

CEN12FA010 10/6/2011 Holland, MI Fatal N2935R Airplane Quickie Aircraft Q200 Built Approach Collision on 

Takeoff or 

Landing

ERA12CA010 10/6/2011 Sebastian, FL Nonfatal N67WR Airplane Velocity RG Purchased Used Landing Collision on 

Takeoff or 

Landing
NTSB The Safety of Experimental Amateur-Built Aircraft

139

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

ERA12LA011 10/6/2011 Wytheville, VA Fatal N7026G Airplane Rand Robinson KR-2 Purchased Used Initial Climb Loss of 

Control in 

Flight

CEN12LA013 10/7/2011 Thompsonville, MI Nonfatal N455BW Gyroplane AutoGyro Calidus Built Landing Loss of 

Control on 

Ground

WPR12CA006 10/10/2011 Diamond, WA Nonfatal N132LL Airplane Bushman Purchased Used Landing Abnormal 

Runway 

Contact

CEN12LA014 10/11/2011 Traverse City, MI Nonfatal N4595P Airplane Zenith Aircraft Company 601XL Built Initial Climb System/

Component 

Failure –

Powerplant

WPR12CA005A 10/11/2011 Madera, CA Nonfatal N506DC Airplane Vans RV4 Built Maneuvering Midair 

Collision

WPR12CA005B 10/11/2011 Madera, CA Nonfatal N427EF Airplane Vans RV8 Purchased Used Maneuvering Midair 

Collision

WPR12LA009 10/13/2011 San Rafael, CA Nonfatal N762S Airplane Pietenpol Air Camper Purchased Used Takeoff System/

Component 

Failure –

Powerplant

CEN12CA027 10/14/2011 Breaux Bridge, LA Nonfatal N610EC Airplane Vans RV8 Purchased Used Landing Collision on 

Takeoff or 

Landing

CEN12CA029 10/15/2011 Blair, NE Nonfatal N29HT Gyroplane American Autogyro Sparrow 

Hawk

Built Takeoff System/Comp

onent Failure 

– Non-Power

WPR12LA013 10/15/2011 Susanville, CA Nonfatal N4077B Airplane Avid Flyer Purchased Used Takeoff System/

Component 

Failure –

Powerplant

CEN12CA026 10/16/2011 Terrell, TX Nonfatal N331EJ Airplane Volksplane VP-1 Purchased Used Initial Climb Loss of 

Control in 

Flight

ERA12CA043 10/17/2011 Grantham, NC Nonfatal N25WS Airplane Aerosport Scamp Purchased Used Approach Collision on 

Takeoff or 

Landing

ERA12LA045 10/18/2011 Woodrow, WV Nonfatal N5456C Airplane Bearhawk Purchased Used Maneuvering System/

Component 

Failure –

Powerplant

CEN12CA035 10/21/2011 Hibbing, MN Nonfatal N43280 Airplane Avid Mark IV Purchased Used En Route System/

Component 

Failure –

Powerplant
NTSB The Safety of Experimental Amateur-Built Aircraft

140

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

ERA12FA018 10/22/2011 Washington, GA Fatal N75654 Airplane Sonex Waiex Purchased Used Maneuvering System/

Component 

Failure – NonPower

ERA12FA021 10/23/2011 Lexington, NC Fatal N795DB Airplane Cozy MK IV Purchased Used Approach Fuel Related

CEN12LA049 10/29/2011 Vienna, OH Nonfatal N486LB Airplane Pietenpol Air Camper Purchased Used Initial Climb System/

Component 

Failure –

Powerplant

ERA12CA055 10/30/2011 Folkston, GA Nonfatal N968TP Airplane Vans RV10 Built En Route Fuel Related

ERA12FA057 11/1/2011 Taylorsville, GA Fatal N262MA Airplane Vans RV6 Purchased Used Unknown Unknown

ERA12LA100A 11/6/2011 Abingdon, VA Nonfatal N62HS Airplane Vans RV6 Purchased Used Landing Runway 

Incursion -

Vehicle

ERA12LA069 11/9/2011 Nashua, NH Nonfatal N220RG Airplane Vans RV8 Built Landing Abnormal 

Runway 

Contact

WPR12CA033 11/9/2011 San Carlos, AZ Nonfatal N5089Q Airplane Thatcher CX4 Purchased Used Takeoff Loss of 

Control on 

Ground

CEN12LA071 11/17/2011 Clinton, AR Nonfatal N274 Airplane Zenith Aircraft Company 

CH602

Purchased Used Takeoff System/

Component 

Failure – NonPower

ERA12CA078 11/20/2011 Bunn, NC Nonfatal N6844B Airplane Kitfox IV-1200 Purchased Used Landing Abnormal 

Runway 

Contact

CEN12CA081 11/23/2011 Center, TX Nonfatal N808F Airplane Davis DA-2A Purchased Used Landing Loss of 

Control on 

Ground

ERA12CA088 11/25/2011 Quinton, VA Nonfatal N816BA Airplane Vans RV7A Purchased Used Initial Climb Fuel Related

ERA12LA087 11/27/2011 Hernando, FL Nonfatal N1321 Airplane Smith Miniplane DSA-4 Purchased Used En Route System/

Component 

Failure –

Powerplant

ERA12CA094 12/1/2011 Caroleen, NC Nonfatal N295JS Airplane Team Rocket F1H Purchased Used Takeoff Runway 

Incursion -

Animal

ERA12FA093 12/1/2011 Fulton, NY Fatal N865JT Airplane Wittman Tailwind W-10 Built Approach Fuel Related

ERA12CA096 12/4/2011 Courtland, AL Nonfatal N212WE Airplane Loehle Aircraft Company 

P5151

Purchased Used Approach Windshear/

Thunderstorm
NTSB The Safety of Experimental Amateur-Built Aircraft

141

NTSB case ID Date Location Severity

Registra-

++tion ++ Aircraft Built or Used

CICTT phase 

code

CICTT event 

code

CEN12LA102 12/8/2011 Festus, MO Nonfatal N7138K Airplane Rans S-13 Purchased Used Approach Loss of 

Control in 

Flight

WPR12FA059 12/10/2011 Surprise, AZ Fatal N724WD Airplane Vans RV7A Built En Route Loss of 

Control in 

Flight

WPR12FA062 12/10/2011 Armistead, CA Fatal N948RC Airplane Vans RV8 Built Maneuvering Low Altitude 

Operation

ERA12FA107 12/11/2011 Somerville, TN Fatal N347DS Airplane Rans S-7 Purchased Used Takeoff Other

ERA12CA124 12/26/2011 Simsbury, CT Nonfatal N435AB Gyroplane Aerial Gyroplane Built Takeoff Loss of 

Control in 

Flight

ERA12CA129 12/30/2011 Mansfield, MA Nonfatal N344MK Airplane Jabiru Calypso Purchased Used Landing Loss of 

Control on 

Ground
NTSB The Safety of Experimental Amateur-Built Aircraft

142

Appendix G: Canadian Minister’s Delegate –

Recreational Aviation Form C14E Fuel Flow Test 

Report 
NTSB The Safety of Experimental Amateur-Built Aircraft

143

Appendix H: Special Light-Sport and 

Experimental Light-Sport Airworthiness 

Certificates and Sport Pilot Airmen Certificate

Effective September 1, 2004, the Federal Aviation Administration (FAA) defined 

characteristics describing a category of simple, small, lightweight, low-performance aircraft; 

identifying them as light-sport aircraft. Along with defining this group of aircraft, the FAA 

created new airworthiness categories and certification procedures for aircraft meeting the 

light-sport definition. Specifically, two categories of special airworthiness certificate were 

created, special light-sport aircraft (S-LSA) which include aircraft manufactured according to an 

industry consensus standard rather than a type certificate, and experimental light-sport aircraft 

(E-LSA), which includes provisions for kit-built versions of S-LSA aircraft, S-LSA 

re-certificated as experimental, and a temporary provision to allow migration of so-called ―fat 

ultralights‖ that included aircraft that did not conform to 14 CFR Part 103 and that were 

previously unregistered into the category of E-LSA aircraft.

At the same time, the FAA created a new sport pilot airmen certificate(s), with associated 

operating limitations that granted privileges to operate aircraft meeting the light-sport aircraft

definition. The sport pilot certificate was envisioned as less expensive and less restrictive entry 

to pilot certification for purpose of personal recreation. As a tradeoff, the operating limitations of 

the sport pilot certificate are more restrictive with regard to the aircraft that can be flown, the 

number of passengers carried, and the time of day during which they could operate. In particular, 

pilots exercising the privileges of the light-sport certificate are restricted to aircraft meeting the 

definition of light-sport aircraft. It is important to note that this not only includes aircraft with an 

S-LSA or E-LSA airworthiness certificates, but any aircraft meeting the definition shown in the 

next section. For example, aircraft with a standard or experimental airworthiness certificate may 

be flown by a pilot exercising the privileges of the sport pilot certificate. 

The most notable of the differences introduced with the sport pilot certificate is the option 

to use a current driver‘s license to meet the airmen medical certification requirements, and the 

extension of this option to pilots holding other levels of airmen certification so long as they 

adhere to the aircraft and operating limitations of the sport pilot certificate. For example, this 

change is related to E-AB aircraft in that a pilot holding a private, commercial, or air transport 

pilot airmen certificate may operate an E-AB or type-certificated aircraft that conforms to the 

definition of a light-sport aircraft (as opposed to the airworthiness certification of S-LSA or 

E-LSA) using a valid driver‘s license to meet the medical certification requirements, so long as 

they adhere to operating limitations of the sport pilot airmen certificate. 

Light-Sport Aircraft Definition

Title 14, Code of Federal Regulations, section 1.1 includes the following definition of 

light sport aircraft:
NTSB The Safety of Experimental Amateur-Built Aircraft

144

Light-sport aircraft means an aircraft, other than a helicopter or powered-lift that, since 

its original certification, has continued to meet the following:

(1) A maximum takeoff weight of not more than—

(i) 1,320 pounds (600 kilograms) for aircraft not intended for operation on water; or

(ii) 1,430 pounds (650 kilograms) for an aircraft intended for operation on water.

(2) A maximum airspeed in level flight with maximum continuous power (VH) of not 

more than 120 knots CAS under standard atmospheric conditions at sea level.

(3) A maximum never-exceed speed (VNE) of not more than 120 knots CAS for a glider.

(4) A maximum stalling speed or minimum steady flight speed without the use of 

lift-enhancing devices (VS1) of not more than 45 knots CAS at the aircraft's maximum 

certificated takeoff weight and most critical center of gravity.

(5) A maximum seating capacity of no more than two persons, including the pilot.

(6) A single, reciprocating engine, if powered.

(7) A fixed or ground-adjustable propeller if a powered aircraft other than a powered 

glider.

(8) A fixed or feathering propeller system if a powered glider.

(9) A fixed-pitch, semi-rigid, teetering, two-blade rotor system, if a gyroplane.

(10) A nonpressurized cabin, if equipped with a cabin.

(11) Fixed landing gear, except for an aircraft intended for operation on water or a glider.

(12) Fixed or retractable landing gear, or a hull, for an aircraft intended for operation on 

water.

(13) Fixed or retractable landing gear for a glider.

Special Light-sport Aircraft and Experimental Light-sport Aircraft Airworthiness 

Certification

Title 14, Code of Federal Regulations, section 21.190 includes the following regulations 

pertaining to certification of special light sport aircraft:
NTSB The Safety of Experimental Amateur-Built Aircraft

145

21.190 Issue of a special airworthiness certificate for a light-sport category aircraft.

(a) Purpose. The FAA issues a special airworthiness certificate in the light-sport category 

to operate a light-sport aircraft, other than a gyroplane.

(b) Eligibility. To be eligible for a special airworthiness certificate in the light-sport 

category:

(1) An applicant must provide the FAA with—

(i) The aircraft's operating instructions;

(ii) The aircraft's maintenance and inspection procedures;

(iii) The manufacturer's statement of compliance as described in paragraph (c) of this 

section; and

(iv) The aircraft's flight training supplement.

(2) The aircraft must not have been previously issued a standard, primary, restricted, 

limited, or provisional airworthiness certificate, or an equivalent airworthiness certificate issued 

by a foreign civil aviation authority.

(3) The aircraft must be inspected by the FAA and found to be in a condition for safe 

operation.

(c) Manufacturer's statement of compliance for light-sport category aircraft. The 

manufacturer's statement of compliance required in paragraph (b)(1)(iii) of this section must—

(1) Identify the aircraft by make and model, serial number, class, date of manufacture, 

and consensus standard used;

(2) State that the aircraft meets the provisions of the identified consensus standard;

(3) State that the aircraft conforms to the manufacturer's design data, using the 

manufacturer's quality assurance system that meets the identified consensus standard;

(4) State that the manufacturer will make available to any interested person the following 

documents that meet the identified consensus standard:

(i) The aircraft's operating instructions.

(ii) The aircraft's maintenance and inspection procedures.

(iii) The aircraft's flight training supplement.
NTSB The Safety of Experimental Amateur-Built Aircraft

146

(5) State that the manufacturer will monitor and correct safety-of-flight issues through the 

issuance of safety directives and a continued airworthiness system that meets the identified 

consensus standard;

(6) State that at the request of the FAA, the manufacturer will provide unrestricted access 

to its facilities; and

(7) State that the manufacturer, in accordance with a production acceptance test 

procedure that meets an applicable consensus standard has—

(i) Ground and flight tested the aircraft;

(ii) Found the aircraft performance acceptable; and

(iii) Determined that the aircraft is in a condition for safe operation.

(d) Light-sport aircraft manufactured outside the United States. For aircraft 

manufactured outside of the United States to be eligible for a special airworthiness certificate in 

the light-sport category, an applicant must meet the requirements of paragraph (b) of this section 

and provide to the FAA evidence that—

(1) The aircraft was manufactured in a country with which the United States has a 

Bilateral Airworthiness Agreement concerning airplanes or Bilateral Aviation Safety Agreement 

with associated Implementation Procedures for Airworthiness concerning airplanes, or an 

equivalent airworthiness agreement; and

(2) The aircraft is eligible for an airworthiness certificate, flight authorization, or other 

similar certification in its country of manufacture.

Title 14, Code of Federal Regulations, sections 21.191(i) and 21.193(e) include the 

following regulations pertaining to certification of special light-sport aircraft, with 

14 CFR 21.191(i)(1) being the provision by which the ―fat-ultralights‖ could be certified as 

E-LSA:

21.191 (i) Operating light-sport aircraft. Operating a light-sport aircraft that—

(1) Has not been issued a U.S. or foreign airworthiness certificate and does not meet the 

provisions of §103.1 of this chapter. An experimental certificate will not be issued under this 

paragraph for these aircraft after January 31, 2008;

(2) Has been assembled—

(i) From an aircraft kit for which the applicant can provide the information required by 

§21.193(e); and
NTSB The Safety of Experimental Amateur-Built Aircraft

147

(ii) In accordance with manufacturer's assembly instructions that meet an applicable 

consensus standard; or

(3) Has been previously issued a special airworthiness certificate in the light-sport 

category under §21.190.

21.193 (e) In the case of a light-sport aircraft assembled from a kit to be certificated in 

accordance with §21.191(i)(2), an applicant must provide the following:

(1) Evidence that an aircraft of the same make and model was manufactured and 

assembled by the aircraft kit manufacturer and issued a special airworthiness certificate in the 

light-sport category.

(2) The aircraft's operating instructions.

(3) The aircraft's maintenance and inspection procedures.

(4) The manufacturer's statement of compliance for the aircraft kit used in the aircraft 

assembly that meets §21.190(c), except that instead of meeting §21.190(c)(7), the statement must 

identify assembly instructions for the aircraft that meet an applicable consensus standard.

(5) The aircraft's flight training supplement.

(6) In addition to paragraphs (e)(1) through (e)(5) of this section, for an aircraft kit 

manufactured outside of the United States, evidence that the aircraft kit was manufactured in a 

country with which the United States has a Bilateral Airworthiness Agreement concerning 

airplanes or a Bilateral Aviation Safety Agreement with associated Implementation Procedures 

for Airworthiness concerning airplanes, or an equivalent airworthiness agreement.

Title 14, Code of Federal Regulations, section 61.315 include the following regulations 

pertaining to the sport pilot airmen certificate:

61.315 What are the privileges and limits of my sport pilot certificate?

(a) If you hold a sport pilot certificate you may act as pilot in command of a light-sport 

aircraft, except as specified in paragraph (c) of this section.

(b) You may share the operating expenses of a flight with a passenger, provided the 

expenses involve only fuel, oil, airport expenses, or aircraft rental fees. You must pay at least 

half the operating expenses of the flight.

(c) You may not act as pilot in command of a light-sport aircraft:
NTSB The Safety of Experimental Amateur-Built Aircraft

148

(1) That is carrying a passenger or property for compensation or hire.

(2) For compensation or hire.

(3) In furtherance of a business.

(4) While carrying more than one passenger.

(5) At night.

(6) In Class A airspace.

(7) In Class B, C, and D airspace, at an airport located in Class B, C, or D airspace, and 

to, from, through, or at an airport having an operational control tower unless you have met the 

requirements specified in §61.325.

(8) Outside the United States, unless you have prior authorization from the country in 

which you seek to operate. Your sport pilot certificate carries the limit ―Holder does not meet 

ICAO requirements.‖

(9) To demonstrate the aircraft in flight to a prospective buyer if you are an aircraft 

salesperson.

(10) In a passenger-carrying airlift sponsored by a charitable organization.

(11) At an altitude of more than 10,000 feet MSL or 2,000 feet AGL, whichever is 

higher.

(12) When the flight or surface visibility is less than 3 statute miles.

(13) Without visual reference to the surface.

(14) If the aircraft:

(i) Has a VH greater than 87 knots CAS, unless you have met the requirements of 

§61.327(b).

(ii) Has a VH less than or equal to 87 knots CAS, unless you have met the requirements of 

§61.327(a) or have logged flight time as pilot in command of an airplane with a VH less than or 

equal to 87 knots CAS before April 2, 2010.

(15) Contrary to any operating limitation placed on the airworthiness certificate of the 

aircraft being flown.

(16) Contrary to any limit on your pilot certificate or airman medical certificate, or any 

other limit or endorsement from an authorized instructor.
NTSB The Safety of Experimental Amateur-Built Aircraft

149

(17) Contrary to any restriction or limitation on your U.S. driver's license or any 

restriction or limitation imposed by judicial or administrative order when using your driver's 

license to satisfy a requirement of this part.

(18) While towing any object.

(19) As a pilot flight crewmember on any aircraft for which more than one pilot is 

required by the type certificate of the aircraft or the regulations under which the flight is 

conducted.

Title 14, Code of Federal Regulations, section 61.303(b) include the following 

regulations pertaining to the driver‘s license medical provision:

61.303 (b) A person using a U.S. driver's license to meet the requirements of this 

paragraph must—

(1) Comply with each restriction and limitation imposed by that person's U.S. driver's 

license and any judicial or administrative order applying to the operation of a motor vehicle;

(2) Have been found eligible for the issuance of at least a third-class airman medical 

certificate at the time of his or her most recent application (if the person has applied for a 

medical certificate);

(3) Not have had his or her most recently issued medical certificate (if the person has held 

a medical certificate) suspended or revoked or most recent Authorization for a Special Issuance 

of a Medical Certificate withdrawn; and

(4) Not know or have reason to know of any medical condition that would make that 

person unable to operate a light-sport aircraft in a safe manner.

The present study did not specifically attempt to assess the impact of the regulatory 

changes related to light-sport aircraft and sport pilot airmen certificate; however, there is 

evidence of those effects in the accident record. Figure H1 illustrates the increase in the 

proportion of accident aircraft meeting the weight definition of light-sport aircraft and Figure H2

illustrates the increase in proportion of E-AB aircraft accidents without a first, second, or third 

class medical. In the absence of associated data, it can be assumed that these findings are 

indicative of an increase in activity related to pilots exercising the sport pilot provision. They do 

not, however, assess the specific risk of these changes in regulation.
NTSB The Safety of Experimental Amateur-Built Aircraft

150

Figure H1. Chart illustrating an increase in the proportion of accident aircraft meeting the weight 

limitation of light-sport aircraft, following the 2004 effectiveness date of the light-sport aircraft 

and sport pilot rule.

Proportion of Accident Aircraft with

Maximum Gross Weight Category 1,320 Pounds

or Less, 2001-2010
NTSB The Safety of Experimental Amateur-Built Aircraft

151

Figure H2. Chart illustrating an increase in the proportion of accident pilots of E-AB aircraft 

without a First, Second, or Third Class medical following the 2004 effective date of the 

light-sport aircraft and sport pilot rule.

0%

10%

20%

30%

40%

50%

60%

70%

80%

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Percentage of E-AB Accident Pilots

Calendar Year

Distribution of E-AB Accident Pilots by Medical 

Certificate, 2001–2010

None/Sport Pilot Class1 Class2 Class3 Unknown