Petition for exemption from certain sections of 14 CFR Parts 21, 43, and 61 where the term “light-sport 

aircraft” is referenced as applied to the Terrafugia Transition® four-wheeled light sport aircraft intended 

for operation on public roadways (roadable aircraft) to permit the vehicle additional weight and stall 

speed such that the Transition® may be treated as a light-sport aircraft for purposes of design, 

airworthiness, production, operation, training, and maintenance.

PETITIONER:

Terrafugia, Inc.

23 Rainin Road

Woburn, MA 01801
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Request for Exemption

November 4, 2014

U.S. Department of Transportation (DOT)

Docket Operations

West Building – Ground Floor, Room W12-140

1200 New Jersey Avenue, SE

Washington, D.C. 20590

(also submitted electronically)

Subject: Request for Exemption for a Roadable Special Light Sport Aircraft 

Attachments: Petition for Exemption: Terrafugia Transition® to Provide Increased Level of 

Crashworthiness and Functional Safety

Dear DOT Representative:

For the past eight years, Terrafugia has been developing the Transition® street-legal airplane for the 

Light Sport Aircraft market. The Transition® incorporates a large number of features that are not 

required for a typical LSA, but that are designed to provide substantial safety benefits. These safety 

features add a significant amount of weight to the aircraft. 

In 2010, in consideration of some of these safety features, the FAA granted us a weight allowance of 110

pounds. Our engineering team made its best effort to refine the design of the safety systems to fit 

within the allowed extra weight, but it was not sufficient to achieve the desired level of safety. 

Therefore, we request a new exemption for the Transition® for additional weight and for stall speed. 

The attached petition outlines the safety and public good bases for our request. 

The Transition® is expected to set the highest bar for occupant safety in general aviation. The LSA 

category will allow these safety advancements to impact the largest possible number of people as 

quickly as possible while minimizing potential procedural conflicts between the FAA and the NHTSA that 

could delay the introduction of features that would have a positive safety impact.

I respectfully request that you grant this petition for exemption. Thank you for your consideration.

Sincerely,

Carl Dietrich, Ph.D.

CEO/CTO 

Terrafugia Inc.

23 Rainin Road

Woburn, MA 01801

carl@terrafugia.com

+1-781-491-0812
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Request for Exemption Page 1 of 23

Petition for Exemption 

for the

Terrafugia Transition® 

to provide an

Increased Level of Crashworthiness and Functional Safety 

Contents 

Specific CFR Sections for Exemption.............................................................................................................1

Introduction ..................................................................................................................................................2

Safety, the Transition®, and why LSA Matters..............................................................................................3

Public Interest...............................................................................................................................................5

Substantiation of Requested Exemption ......................................................................................................8

Description of the Exemption Relief Sought...............................................................................................16

Conclusion...................................................................................................................................................16

Appendix 1: Additional Safety Commitment and Features of the Transition®...........................................19

Appendix 2: Discussion of Sport Pilot Flight Operations ............................................................................21

Appendix 3: Anticipated Transition® Training Program..............................................................................22

Specific CFR Sections for Exemption 

Terrafugia requests an exemption from specific aspects of Title 14 of the Code of Federal Regulations

(CFR) Sections 21, 43, and 61 as follows: 

§21.175 §43.1 §61.1 §61.325

§21.181 §43.3 §61.23 §61.327

§21.182 §43.7 §61.31 §61.403

§21.190 §61.45 §61.405

§21.191 §61.89 §61.411

§21.193 §61.113 §61.415

§61.303 §61.417

§61.305 §61.419

§61.315 §61.423

§61.317 §61.429

§61.321
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Request for Exemption Page 2 of 23

Introduction 

The Terrafugia Transition® is designed to be a Light Sport Aircraft (LSA) that is capable of folding its wings 

and driving on roads and highways. Often referred to as a “flying car” in the media, the Transition® is 

much more accurately described as an airplane that can drive, or as a roadable aircraft. Terrafugia has 

successfully conducted flight and drive testing of two prototype Transition® aircraft, with first flights in 

March of 2009 and March of 2012.

Now nearing pre-production, Terrafugia requests that the Transition® be treated within the CFRs as a 

light-sport aircraft despite having additional weight and a higher stall speed than that established within 

the definition of a Light Sport Aircraft (LSA)1. This allowance will enable the Transition® roadable aircraft 

to be designed, manufactured, certificated, flown, used for flight instruction, and maintained under the 

regulations governing LSA and the corresponding accepted consensus standards; this is consistent both 

with the design and characteristics of the Transition® as well as with the intent of the LSA category.

The primary driver for the additional weight is the incorporation of systems and structure necessary for 

safe road use in general and crashworthiness in particular. In order to be road-worthy, the Transition® 

has been designed to comply with a number of the Federal Motor Vehicle Safety Standards (FMVSS), most 

notably frontal impact crash scenarios2. The occupant protection features incorporated into the 

Transition® to meet these FMVSS-based crash scenarios, which are anticipated to provide additional 

crashworthiness from an aircraft perspective as well, incur substantial weight penalties over the structure 

typically found in an LSA. As a result, Terrafugia requests an allowable increase in gross takeoff weight

beyond the current 1,320 lb limit. .

This additional weight in turn drives Terrafugia’s petition for an increase in allowable stall speed. Due to 

the dimensional constraints of road use (e.g., lane width, parking space size, garage height, etc.), it is not 

feasible to simply increase the wing area proportionally to the increased weight. Based on a spectrum of 

pilot experience, Terrafugia believes that the necessary stall speed increase will not affect the underlying 

safety intent of an easy-to-fly LSA3. Therefore, Terrafugia is also requesting an increase in the maximum 

stall speed for the Transition® beyond the 45 knot limit found in 14 CFR §1.1.

A previous exemption4for the Transition® was granted by the Federal Aviation Administration (FAA) in

2010, allowing the Transition® a maximum takeoff weight of 1,430 lb. Extensive design, analysis, and 

prototyping work has shown that this weight limit is insufficient to accommodate the design features 

necessary to provide the road-worthy level of safety and durability that the Transition® requires. In the 

time since our initial exemption, the FAA has demonstrated a willingness to grant significant additional 

weight requests within the LSA category when substantiated by compelling safety arguments and in the 

public interest. The Transition® incorporates not only similar operational functionality to that described 

in these other exemption requests (discussed in Appendix 1), but many additional crashworthiness and 

 

1 14 CFR §1.1

2 The key frontal impact crash scenarios from 14 CFR §571.208 are a 30 mph impact at a 30° offset angle and 35 

mph impact straight-on.

3

See Appendix 1 for other relevant characteristics of the Transition® that improve in-flight safety. Sport Pilot 

operations are addressed in Appendix 2.

4 Docket No. FAA-2009-1087
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Request for Exemption Page 3 of 23

crash-avoidance features as well; the following discussion provides details of these enhanced safety 

aspects of the Transition®. 

Safety, the Transition®, and why LSA Matters 

The LSA category and Sport Pilot Certificate were created in part to reinvigorate growth and innovation 

within general aviation, while supporting the FAA’s charter to oversee and enhance the safety of the flying 

public. The Transition®, by its very design, is poised to meet all of these goals: to contribute to the growth 

of the general aviation (GA) market, to introduce cutting-edge innovation into today’s flight vehicles, and 

– most importantly – to provide unprecedented safety to the pilots and passengers of the vehicle.

One of the key safety benefits of the Transition® is that pilots will no longer be tempted to fly into marginal 

conditions for fear of being stranded by poor weather; instead, they can land at the nearest airport and 

drive safely to their destination. However, in order to realize this additional utility, the Transition® must 

be designed to meet minimum safety standards for road use as well as much of the Federal Motor Vehicle 

Safety Standards (FMVSS) pertaining to Multi-Purpose Passenger Vehicles. This drives a level of crash 

safety and occupant protection unmatched in other light aircraft through energy absorption features, 

maintenance of a survivable cabin volume, and proven occupant restraint technology.

 

The Transition® on the road and in flight.

With the exception of its restrictive weight and stall speed definition, the LSA regulatory structure 

provides the best home for the Transition® and its accompanying safety benefits for multiple reasons: 

 LSA brings these safety benefits to the pilot population most capable of expansion and thus 

potentially newest to aviation; e.g., Sport Pilot Certificate holders. This market expansion 

potential is seen in the order backlog for the Transition®: it has attracted new people to aviation 

and encouraged non-current pilots to come back to flying. 

 LSA allows for a low-overhead approach to continual improvement of the design once in service. 

This will be crucial for maintaining the design in step with evolving FMVSS regulations. It will also 

simplify improvements to the safety features of the vehicle based on any lessons learned from 

the in-service fleet. 

 LSA works with the industry consensus standards process that is nimble enough to adapt to 

changing technologies; for example, an annex to the Standard Specification for Design and John Slemp
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Request for Exemption Page 4 of 23

Performance of a Light Sport Airplane (ASTM F2245-13) for roadable aircraft is already under 

development within ASTM Committee F37, with Terrafugia’s technical leadership. 

LSA thus offers a mechanism by which the safety innovations of the Transition® can be offered to more 

pilots in a shorter time frame and at a lower cost than other certification options, thus increasing and 

accelerating their impact on the overall safety of the industry. LSA is intended to provide aircraft that are 

simple and easy to fly. The Transition® is just that: stable and simple to operate, without flaps, providing 

large stall margin on takeoff, and delivering a simple “fly it onto the runway” approach to landing.

By requesting relief to allow the Transition® to be treated by the CFRs as an LSA, Terrafugia seeks to allow 

the Transition® to interact with the aircraft certification process, pilots, and maintenance providers and 

procedures in the same manner as any other LSA. The addition of roadability and crashworthiness does 

not add complexity to the operation or maintenance of the aircraft; from conception, the Transition® has 

been designed to meet both the LSA standards and the spirit of the Light Sport category as a simple, safe, 

fun, entry-level airplane capable of significant market expansion.

This light-sport-based regulatory interaction is critical to the success of the Transition® and the realization 

of the safety and public interest benefits discussed here and in the following sections. While other 

possible certification options exist, they do not facilitate the innovation, responsiveness, and market 

growth that is supported by LSA. Both Primary Category and requiring a Private Pilot Certificate add 

detrimental overhead to the Transition® program, and therefore serve as an impediment to introducing 

the additional safety benefits to the public in a timely and sustainable fashion.

Requiring the Transition® to receive a Type Certificate would limit Terrafugia’s ability to make 

improvements to the product based on early field use and to make any adjustments that are necessary as 

a result of a change in applicable road regulations. Terrafugia intends to begin production with a limited 

number of Premier Edition aircraft: ten early production, “Block 1” aircraft delivered over the first year of 

production. Premier Edition customers will receive a high level of support from the company. As entryinto-service issues are discovered, corrective actions can be taken and incorporated into a “Block 2” 

design. This is particularly important given the limited field experience with products like the Transition®:

there will likely be more need for adaptation based on early usage than with a conventional aircraft. There 

is also the possibility that NHTSA could require Terrafugia to retrofit vehicles in the field through a 

standard recall process. Without the flexibility and adaptability of LSA, this process would become overly 

burdensome and could result in the delayed implementation of safety and other improvements.

Another situation in which the adaptability of LSA is critical to public safety and the success of the 

Transition® program is that of changing automotive requirements. Terrafugia intends to steadily increase 

the level of FMVSS compliance for the Transition®, beginning with the Specialty Vehicle category, moving 

into the Multipurpose Passenger Vehicle5 designation with line-item exemptions granted by the NHTSA6, 

and eventually achieving a goal of full FMVSS compliance. This steadily increasing level of safety and 

 

5 49CFR 571.3(b) states: “Multipurpose passenger vehicle means a motor vehicle with motive power, except a lowspeed vehicle or trailer, designed to carry 10 persons or less which is constructed either on a truck chassis or with 

special features for occasional off-road operation."

6 Docket NHTSA-2010-0154
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Request for Exemption Page 5 of 23

crashworthiness will require substantial continuing investment from the company. Additional overhead 

associated with making these changes could cause safety improvements to be delayed.

In similarity to the LSA process, road vehicle manufacturers are expected to declare compliance to the 

FMVSS that are applicable to their vehicle at the time of its production, not at a fixed point in time as with 

a Type Certificate. In addition to the voluntary increases in safety and regulation that are anticipated for 

the Transition®, changes to the FMVSS over time may necessitate adjustments to the Transition® design. 

Working within the LSA category from an aviation perspective makes these changes much more tractable.

Beyond the opportunities for steadily increasing safety and market growth that the flexibility of Light Sport 

will provide for the Transition®, LSA may very well be critical to the realization of the Transition® in its 

entirety. The Transition® program progress to date has underscored the magnitude of the technical 

challenge associated with combining driving and flying in a safe and practical manner. Further potential 

delay and program overhead, as could reasonably be expected by having to go through the Type 

Certification process, could result in the inability of Terrafugia to continue to invest in bringing the 

Transition® to market. This potentiality would mean that none of the safety benefits to the flying and 

general public of the Transition® would be realized.

Public Interest 

Allowing the Transition® to come to market within the LSA category is in the public interest. Both short 

and long term benefits exist, spanning areas as diverse as General Aviation utility and safety, economic 

benefit to the U.S., STEM7 education and inspiration, and establishing a key first step in the advancement 

of the value of personal aviation to the people of the United States by addressing the largest barriers to 

the more widespread use of GA for transportation.

General Aviation Safety - Crashworthiness

Throughout this document, the benefits of adding crashworthiness features to the Transition® are 

discussed. Personal aviation currently experiences fifteen times more fatalities per billion miles traveled 

than occur while driving (refer to Appendix 1). While certainly some of that difference can be attributed 

to the difference in the energy of the collisions involved, automotive-style crashworthiness features such 

as energy absorption, a safety cage, and occupant protection have the potential to dramatically reduce 

the number of small aircraft accidents that result in fatalities. 

The value of incorporating these sorts of crashworthiness features into a light aircraft, and the broader 

interest of the GA industry in the pioneering work that Terrafugia is doing in this area, has been made 

apparent at events where Terrafugia has presented lessons learned, including: the Part 23 Aviation 

Rulemaking Committee in Pittsburgh, PA in May, 2012; the Crashworthiness Workshop held as part of the 

standards generation process within the ASTM F44 Committee for General Aviation Aircraft in Wichita, KS 

 

7

STEM stands for “Science, Technology, Engineering, and Math” and is used throughout the education and 

technology industries as a buzzword in discussions on how to increase the level of and interest in technical 

education for students in the U.S.
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Request for Exemption Page 6 of 23

in February, 2013; and the 7th Triennial Fire and Crash Safety Conference in Philadelphia, PA in December, 

2013.

When in production, the Transition® will serve as an example to the GA industry of what can be 

accomplished with the incorporation of crashworthiness features into light aircraft. The field experience 

that is gained with the Transition® will also help drive future improvements in crashworthiness both for 

later models of the Transition® itself and other products developed by Terrafugia, not to mention similar 

vehicles developed by others in the future. Granting this exemption petition is the first step from a 

regulatory perspective to fully realizing the potential safety benefits of incorporating automotive-style 

crashworthiness into GA aircraft.

General Aviation Safety - Weather

According to the 2011 AOPA Aviation Safety Institute’s 2011 Nall Report, “Fatal weather accidents are 

among the most difficult to investigate, and weather accidents are the most consistently fatal” with a 

lethality of at least 50%. The Report continues: “Available data do suggest that, as always, attempts to fly 

by visual references in instrument conditions accounted for the lion’s share of fatalities.” This VFR into 

IMC type of accident has a fatality rate of 72%.

While pilot training and instrumentation have both been brought to bear by the aviation community in an 

attempt to reduce the number of weather-related fatalities, no clear downward trend has emerged in the 

accident statistics. This suggests that a novel approach is required: provide the pilot a completely 

different, and significantly more attractive, alternative to flying into marginal weather conditions. By 

providing the alternative of diverting to a nearby airport at the first sign of inclement weather, folding the 

wings in under a minute, and continuing the trip safely on public roads and highways, the Transition® 

allows a pilot to complete a trip without either being grounded indefinitely for weather or potentially 

putting themselves in a dangerous weather-related position in the air.

Economic Benefit

On average, a U.S. commuter spends 54 minutes in traffic each day, going a paltry 17mph8. It is also worth 

noting that 8% of commuters travel longer than 60 minutes one way9. Combined with the number and 

earnings of full-time wage and salary workers in the U.S., this represents over $650 billion in lost 

productivity10. Beyond the monetary cost of commuting, a host of health and emotional problems result 

from long commutes including obesity, stress, divorce, and insomnia11. While the Transition® won’t 

single-handedly solve America’s traffic problem, it is a key step towards a transportation future that 

utilizes personal aviation more and automotive commuting less. Many of Terrafugia’s early reservations 

for the Transition® are from individuals that have an onerous commute and look forward to the additional 

 

8 U.S. Department of Transportation, OmniStats Vol. 3, Issue 4, October 2003.

9 McKenzie, Brian. “Out-of-State and Long Commutes: 2011” American Community Survey Reports, US Census 

Bureau, Issued February 2013, ACS-20.

10 U.S. Bureau of Labor Statistics Economic News Release for July 24, 2014 

(http://www.bls.gov/news.release/wkyeng.nr0.htm) reports 106.6 million full-time workers with median earnings 

of $780 per week in Q2 of 2014

11 http://www.slate.com/articles/business/moneybox/2011/05/your_commute_is_killing_you.html
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Request for Exemption Page 7 of 23

freedom, flexibility, and fun that the Transition® will provide to them. The Transition® is also a “proof of

process” product for the emerging flying car industry; future products that are enabled by the creation of 

this industry (like Terrafugia’s TF-XTM) do have the potential to provide a material improvement to the 

state of commuting in the U.S.

Terrafugia and the Transition® are also a classic example of a small American company revitalizing an old 

U.S. industry, creating jobs and inspiring innovation in the process. While GA is a quintessentially 

American industry, the number of active pilots has been in decline for many years12. This results in the 

loss of manufacturing jobs (including 750 jobs lost, mostly in Kansas, in Q2 of 201413) and other economic 

stimulus from the GA industry. In 2005, this impact was estimated to be $40 billion14. Terrafugia’s current 

forecasts, based on existing order backlog and third party market research, indicate that within five years 

of production deliveries could exceed 500 units annually with over 800 jobs created. Even more 

encouraging for the GA industry, it is anticipated that approximately 30% of the Transition® aircraft sold 

will represent market expansion beyond the current 599,000 active pilots in the U.S.15

If Transition® is viewed in the context of an initial product in an emerging industry, the potential longterm benefit to the American economy of the product suite it will enable could be comparable to that of 

the existing automotive industry.

STEM and Innovation Inspiration

Terrafugia’s efforts in pursuing the Transition® have been an inspiration not just to other companies 

within the personal aviation and “flying car” space, but to countless students and educators throughout 

the country. Terrafugia has invested the time and energy of its founders and team members extensively 

in educational outreach and speaking engagements throughout the U.S. and internationally. Events have 

ranged from participating in forums held annually at EAA’s AirVenture in Oshkosh, WI; to speaking at TED 

Global in Scotland16; to exhibiting the Transition® Proof of Concept at the Boston Museum of Science; to 

being the keynote speakers at the 10th Annual Massachusetts STEM Summit17; to small group student 

presentations at colleges, universities, and technical high schools; and much more.

The media attention given to the Transition® and Terrafugia has also provided an opportunity for GA to 

receive widespread, mainstream, positive press coverage. With coverage in national outlets such as the 

Wall Street Journal, CNN, CNBC, the Today Show, FOX, the New York Times, and many others, Terrafugia 

has been able to reach an audience previously unexposed to personal aviation. In at least one case, this 

coverage led an individual to research the company, reserve a Transition®, achieve his Sport Pilot 

 

12 General Aviation Manufacturers Association (GAMA) 2012 General Aviation Statistical Databook and Industry 

Outlook.

13 http://www.kansas.com/2014/04/23/3418915/cessna-aircraft-beechcraft-start.html

14Allen, Bruce, Blond, David, and Gellman, Aaron, “General Aviation’s Contribution to the U.S. Economy”, General 

Aviation Manufacturer’s Association, May 2006.

15 Estimated Active Airmen Certificates Held as of December 31, 2013, FAA US Civil Airmen Statistics 

(http://www.faa.gov/data_research/aviation_data_statistics/civil_airmen_statistics/2013/)

16 https://www.ted.com/talks/anna_mracek_dietrich_a_plane_you_can_drive

17 http://www.terrafugia.com/news/terrafugia-stem-presentation
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Request for Exemption Page 8 of 23

certificate, move to an airpark, and continue to fly existing aircraft and pursue additional certifications 

while waiting for his Transition®.

By granting this petition and allowing the Transition® to come to market in the most expeditious and 

accessible manner, this positive impact will be magnified. Further delaying the entry into service of the 

Transition® by imposing a Type Certificated approach will dampen this enthusiasm and significantly 

reduce the resources that Terrafugia has available to devote to STEM outreach and general public 

inspiration.

Substantiation of Requested Exemption 

Despite the increased technical challenge that including FMVSS-based design requirements imposes, 

Terrafugia has chosen to pursue this more safety-conscious path. While Terrafugia plans a phased 

approach to increasing levels of road-use certification, the requirements imposed on the Transition® 

design are based on those of a Multi-Purpose Passenger Vehicle18 as defined by the National Highway 

Traffic Safety Administration (NHTSA). This choice to pursue an overall higher level of safety in a way not 

contemplated by either NHTSA or FAA regulations necessitates special relief from both agencies. In 

consideration of the unique benefits and challenges of the Transition®, relief has already been granted by 

NHTSA in the form of four specific exemptions to sections of the FMVSS19. 

The safety features required by the FMVSS-based design requirements provide significant benefit to the 

aircraft aspects of the Transition® as well, both in the operational utility described above and in the 

increased occupant protection in the event of an accident. In addition to these FMVSS-driven features, 

Terrafugia is also choosing to include the latest aviation-safety design features, such as a Ballistic Recovery 

System (BRS) – again, a feature not typically found in the GA arena. We are therefore asking the FAA to 

join with NHTSA in allowing the regulatory exemptions that these features require.

The additional safety features include: energy absorbing crush structures; a “safety cage” chassis design 

that preserves a survivable volume for the occupants in the event of a collision; and occupant protection 

devices such as airbags, knee bolsters, head impact protection, and self-tensioning and load-limiting

seatbelts. Beyond these discrete features that are atypical for aircraft designs, the basic structural 

requirements driven by the crash loading scenarios are far more demanding than those driven by flight 

loading, even at the limits of the flight envelope. The enhanced structure and the additional components 

all add weight to the aircraft, which in turn drives the need for a higher stall speed as wing span is limited 

by the maximum dimensions allowed for road use.

 

18 49CFR571.3: “Multipurpose passenger vehicle means a motor vehicle with motive power, except a low-speed 

vehicle or trailer, designed to carry 10 persons or less which is constructed either on a truck chassis or with special 

features for occasional off-road operation [boldface added].”

19 Docket NHTSA-2010-0154. Relief was granted to certain sections of 49CFR571 sections 110, 126, 205, and 208.
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Request for Exemption Page 9 of 23

The table below provides a summary of the various weight penalties for the Transition® due to the 

addition of these safety features.

Summary Table of Requested Weight Exemption for Crashworthiness and Occupant Safety

Basic LSA Weight Definition 1,320 lb

Safety Feature Weight Penalty

Occupant Protection – Structural

 Survivable Volume 44 lb

 Energy Absorption 25 lb

Total Structural Components 69 lb

Occupant Protection – Non-Structural

 Seat Belt System 13 lb

 Knee Bolsters 10 lb

 Door Retention and Functionality 13 lb

 Seats and Headrests 10 lb

 Head Impact Protection 6 lb

Total Occupant Protection Systems 52 lb

Roadability Systems

 Fuel Measurement & Containment 8 lb

 Ground Handling (Steering, Suspension, & Braking) 150 lb

 Ground Drive System 84 lb

 Ground Visibility 24 lb

Total Roadability Systems 266 lb

Enhanced Flight Safety

 Ballistic Recovery System 36 lb

Total Enhanced Flight Safety 36 lb

Total Weight Penalty 423 lb

Contingency (weights shown are estimates) 57 lb

Requested Maximum Takeoff Weight 1,800 lb

As shown in the above table, the components and systems necessary to provide the safety enhancements 

that are central to the design philosophy and value proposition of the Transition® require more than 400

pounds of structure and equipment that are not found in typical LSA. Adding a small contingency to these 

estimated values (<15%) yields the requested exemption value of 1,800 pounds. This in turn precipitates 

the need to request a stall speed increase to 54 knots.

Terrafugia believes that this additional weight brings significant improvements in safety and functionality 

while maintaining the essence of an LSA. There is no resulting compromise in the ease with which the 

Transition® can be flown, nor in its ability to both grow the aviation marketplace and serve as a proving 

ground for crashworthiness innovations that could eventually permeate the GA industry.

The following discussions provide detailed explanations of the systems summarized in the above table.
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Request for Exemption Page 10 of 23

Occupant Protection – Structural

The combination of survivable volume and energy absorption (described below) results in the Transition® 

having a structural design that is significantly different than most light aircraft. Typically, in a tractor 

configuration aircraft, the engine mounts at the front of the airplane are very strong and rigid; aft of that 

structure is the cockpit. Aft of the cockpit (or coincident with a portion of it) is the main spar, another 

substantial structure designed to carry flight loads. In an effort to save weight, the structure surrounding 

the cockpit is typically much less robust than the structure of either the engine mounts or the main spar 

attachment. Thus, in the event of an impact, the energy of the crash is absorbed in part by the 

deformation of the cockpit structure. 

This is detrimental to survivability both in that the majority of the energy of the impact is transferred into 

the cockpit area and in that the occupants can be impacted by the aircraft structure or components 

intruding into the cockpit as they deform. By using an automotive-style configuration of a dedicated 

crushable volume in the front of the vehicle followed by a rigid and structurally robust passenger 

compartment, the Transition® lowers the energy that the occupants will be exposed to in an impact while 

reducing injury by preventing intrusion into the cockpit.

Survivable Volume

Often referred to as a “safety cage” in the automotive industry, the structure of the vehicle 

immediately around the occupants must remain intact during a crash, surviving the impact loads with 

minimal deformation while simultaneously anchoring other vehicle components (e.g., the engine) in 

such a way as to prevent them from intruding into the cockpit. For FMVSS-specified crash scenarios20, 

this means that the structure of the Transition® must withstand acceleration loads upwards of 30g. 

Compared to flight loads, these crash conditions provide the most severe loading case required of the 

structure by more than a factor of 3.

In order to provide the necessary level of structural integrity, Terrafugia is using state-of-the-art 

AGATE pre-impregnated carbon fiber composite materials for the structure. The structure of the 

Transition® also incorporates automotive chassis architecture,such as A- and B-pillars (the substantial 

beams on the front and back of the front doors), a front bulkhead that prevents cabin intrusion and 

deformation at the occupants’ legs, a structural firewall and hard points that prevent the engine from 

moving forward into the cabin, over-cabin beams that prevent roof crush in the event of an inverted 

impact (e.g. roll-over), and increased structural strength along the longitudinal axis of the vehicle.

The weight penalty of providing this fundamental structural component of crashworthiness in the 

Transition® is approximately 44 pounds.

Energy Absorption

While the survivable volume is designed to remain rigid and intact during a collision, other parts of

the vehicle—the “crumple zone” and bumpers—absorb the energy of the collision through 

deformation. This reduces the amount of energy that is ultimately transferred to the vehicle 

occupants, thus lowering the severity of any injury. This energy absorption is accomplished in the 

 

20 See FMVSS 49CFR571.208
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Transition® with front and rear bumpers for low-energy impacts and extruded-aluminum longitudinal 

“crash rails” in the nose of the vehicle which are designed to predictably and evenly absorb the energy 

of a frontal impact through deformation. Such systems are not typically found in light aircraft despite 

early research that shows that energy absorption technology would improve GA crash safety21.

Screen shot of dynamic simulation of energy absorbing crush rails.

Independent of FMVSS considerations, it is particularly important to include dedicated energy 

absorbing structures in an all-composite aircraft from an aviation crashworthiness perspective. 

Traditionally-designed composite structures have been shown to transfer higher accelerations to the 

occupant compartment than all-metal aircraft due to the prevalence of brittle structural failure in a 

crash22.

The weight penalty of the energy absorption systems in the Transition® is approximately 25 pounds.

Occupant Protection – Non-Structural

According to a report on aviation safety published by the NTSB in 2011, “about 20 percent of aviation 

deaths would be preventable if occupants were protected by better restraint systems”23. The most 

common cause of death noted on autopsies (86%) for pilots in GA airplane accidents is blunt trauma24. 

Many of these could potentially have been prevented if proper occupant protection had been in place in 

the aircraft. Such occupant restraint and safety systems are another way the Transition® provides an 

increased level of safety and are another departure from basic LSA. For example, only basic seat belts are 

required by ASTM F224525; the Transition® seatbelts, in contrast, have locking retractors and load-limiting 

 

21 Keilas, S. and Knight, Jr., N. F., “Design, Fabrication, and Testing of Composite Energy-Absorbing Keel Beams for 

General Aviation Type Aircraft”, NASA / CR-2002-212133.

22 Jones, L. E. and Carden, H. D., “Overview of Structural Behavior and Occupant Responses from a Crash Test of a 

Composite Airplane”, SAE International General, Corporate and Regional Aviation Meeting and Exposition, Wichita, 

KS, May 3-5, 1995. NASA-TM-111954.

23 “Airbag Performance in General Aviation Restraint Systems”, NTSB Aviation Safety Study, NTSB/SS-11/01.

24 Weignmann, D.A. and Taneja, N., “Analysis of Injuries Among Pilots Involved in Fatal General Aviation Airplane 

Accidents”, Accident Analysis and Prevention, vol. 35, no. 3 (1997), pp. 571-577.

25 F2245-13 6.10.2
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Request for Exemption Page 12 of 23

features26. A variety of other features are incorporated as well, such as knee bolsters to help keep the 

occupants located appropriately in their seats during a frontal collision. These systems significantly 

exceed those required by ASTM F2245 in both their existence and functionality.

Seat Belt System

The seat belt system employed in the Transition utilizes both retractors and load limiters. A retractor 

removes slack to make the seat belt more effective, yet allows the belt to move with the wearer during 

normal operation. In the case of rapid vehicle deceleration or rollover, the retractor locks to prevent 

the belt from spooling out, thus limiting the movement of the occupant. If the deceleration is high 

enough, the load-limiting feature deploys additional belt in a controlled way to decelerate the 

occupant at a constant load level, better managing occupant energy and reducing injury.

Neither retractors nor load-limiting features are required for GA aircraft and are not typically found 

in them. To function properly this seatbelt system includes not just the webbing, retractors, load 

limiters, and buckles, but also the mounting hardware and structure necessary to react the forces 

experienced by the belts in the event of an impact27. The seatbelt system in the Transition® exceeds 

the level of safety required for LSAs while providing a more comfortable experience.

The weight penalty of the seatbelt system in the Transition® is approximately 13 pounds.

Knee Bolsters

Knee bolsters are energy absorbing structures attached to the bottom of the dashboard such that in 

an impact, if the occupant moves forward in the seat, their knees contact the bolster instead of 

contacting the less compliant structure or going under the dash into the foot well. This simple safety 

technology is ubiquitous in the automotive industry but rarely – if ever – seen in GA aircraft. By 

keeping the occupants from “submarining” under the dashboard and by protecting the femur, the 

potential for serious leg injury is reduced. Preventing leg injury is critical to the ability of the occupants 

to egress the aircraft in the event of an accident. 

In addition to the energy absorbing structure of the knee bolsters, they must be mounted to a 

substructure capable of reacting their loads during an impact. This requires a more substantial 

dashboard structure than is typically found in an LSA.

The weight penalty of the knee bolsters in the Transition® is approximately 10 pounds.

Door Retention and Functionality

From a crashworthiness perspective, the doors provide several functions: they must retain the 

occupants inside the vehicle during the impact, contribute to the integrity of the safety cage, and be 

able to be opened following an impact28. In the Transition® this is accomplished by use of automotive 

 

26 Self-tensioning allows the belt to move with the wearer during normal operation, thus eliminating excess slack 

and increasing comfort. Locking prevents the belt from spooling out during an impact, and it engages the load 

limiting feature. Load-limiting deploys slack in a controlled way to decelerate the occupant at a constant load 

level, better managing occupant energy and reducing injury.

27 See FMVSS 49CFR571.209 and .210 for Seat Belt Assemblies and Anchorages.

28 See FMVSS 49CFR571.206 for door locks and door retention components
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style door beams, latches, and hinges. The doors also have a double acting latch (as is standard in 

automobiles) to prevent inadvertent opening.

The weight penalty of these additional components and functionality in the Transition® is 

approximately 13 pounds.

Seats and Headrests

Due to its use on the road, the adjustable seats in the Transition® must be designed to withstand 

significantly higher loads than what would ordinarily be seen in LSA operations: in any position they

must withstand accelerations of over 25g (longitudinally). Headrests are therefore critical to 

preventing severe neck injuries. The combination of a robust seat with headrests and the other 

occupant restraints discussed above means that the occupants will stay anchored within the 

survivable volume during an impact. 

The weight penalty of the FMVSS-compliant seats and headrests in the Transition® is approximately 

10 pounds.

NOTE: Terrafugia has invested significant design resources to create a custom, lightweight, FMVSS-compliant seat 

for the Transition®. Without this custom component, this weight increase would be in excess of 60 lb.

Head Impact Protection

In addition to headrests, which are padded to further reduce injury, the FMVSS specify head impact 

protection throughout the cockpit. While wearing seatbelts reduces the potential for occupants to 

contact the interior of the cockpit in a collision, head impacts might still occur. In that event, the 

component that is coming into contact with the occupant’s head should be designed to minimize 

injury and absorb energy of the collision. While not standard practice in the LSA industry, much of 

the design of modern automobile interiors derives from this requirement. By eliminating sharp or 

pointy items within the “head arc” of the occupants and by adding padding to absorb impact energy, 

serious brain injury can often be prevented. Providing FMVSS-style head impact protection is an 

additional way in which the Transition® provides a level of crashworthiness and occupant injury 

protection far beyond that of typical light aircraft.

The weight penalty of the purpose-built automotive foam utilized specifically for head impact 

protection throughout the Transition® cockpit is approximately 6 pounds.

Roadability Systems

As discussed earlier, avoidance of accidents resulting from flight into bad weather (VFR into IMC) is 

addressed by the basic functionality that the Transition® offers with its ground drive capability. Highwaycapable steering, suspension, and braking capabilities are necessary to realize this functionality, and help 

pilots avoid accidents both while driving and while taxiing. Furthermore, crashworthiness and occupant 

safety extend beyond the aircraft’s ability to protect its occupants from the impact to the avoidance of 

fuel spillage, and even to the avoidance of the accident itself. Fuel containment and prevention of fuel 

starvation through more accurate fuel gauges are both functions of the crashworthy fuel bladder design

found in the Transition®. 
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Fuel Measurement and Containment

Fuel management is the fourth leading cause of pilot-related accidents, according to the 2011 Nall

Report. While aircraft gauges are only required to be accurate when empty, the automotive industry 

expects dependable accuracy for the fuel gauge throughout the fuel tank’s usable volume, thus 

reducing instances of fuel starvation.

In order to contain fuel during and after an impact, as well as to provide a fuel tank configuration for 

which a greater level of gauge accuracy can be achieved than in typical light-aircraft-style wing tanks, 

fuel is stored in the Transition® in a central bladder protected by dedicated structure located below 

and behind the passenger compartment. This allows fuel to be retained in the event of an impact—

even a side impact—and results in a deeper tank, which improves gauge accuracy.

The weight penalty of the structure required to support the fuel bladder and the system necessary to 

provide accurate fuel gauge readings in the Transition® is approximately 8 pounds.

Ground Handling (Steering, Suspension, and Braking)

While few fatalities actually occur from accidents during the landing phase of flight, such events are 

nonetheless numerous and can cause serious injury in addition to property damage. By virtue of the 

fact that the Transition® landing gear (i.e., suspension) is capable of withstanding bumps and potholes 

while driving, accidents due to hard landings, off-field landings, and suboptimal runway conditions 

are anticipated to be much lower than for the LSA industry at large. Given the LSA category’s role in 

training and introducing new pilots to aviation, this additional robustness is particularly critical.

In addition to being critical for driving, the steering and braking abilities of the Transition® make it 

easier and safer than in other LSAs both to land and to taxi. Theses abilities also enhance the vehicle’s 

controllability on takeoff and landing while on the runway.

A Stanford engineering rule-of-thumb estimate29 puts the typical LSA landing gear system at just over 

50 lb. Based upon this, the weight penalty of the combined suspension, steering, and braking systems 

on the Transition® is approximately 150 lb.

Ground Drive System

Ground drive capability for the Transition® is provided through a gear box that allows the pilot—when 

stopped, on the ground, with the engine off—to shift between powering the propeller and powering 

the wheels. Forward, neutral, and reverse gears are provided for driving, as is a continuously variable 

transmission to allow the required range of speed during road operation.

 

29 http://adg.stanford.edu/aa241/structures/WEIGHTS.HTML
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The Transition® converting between flight and drive modes: its electro-mechanical system is activated from 

inside the cockpit when the plane is stopped, on the ground, with the engine off.

To protect the propeller from debris while driving and to facilitate the energy absorption structure on 

the front of the plane (discussed above), the Transition® has a pusher-configuration propeller. This 

requires a drive shaft from the engine as well as additional structure to support the propeller mount. 

The positioning of the propeller on the Transition® is also critical to a key stall warning safety feature 

which is described in Appendix 1 of this document.

The weight penalty for the gear box and propeller-drive system on the Transition® is approximately

84 pounds.

Ground Visibility

For safe operation on the road – and particularly to fulfill the functional expectation and safety benefit 

of being able to drive in the event of inclement weather – the Transition® includes mirrors, rear-view 

cameras and screens, and a windshield wiper/washer system. Between the windows, mirrors, and 

cameras on the Transition®, all blind-spots are effectively eliminated. All of these items are critical to 

the safety of the Transition®, and are not typically found on light aircraft.

Not only is visibility important for the operator of the Transition®, it is critical that the Transition® be 

visible to other ground traffic. As such, external lighting including headlights, turn indicators, brake 

lights, marker lights, and reverse lights has been included.

The weight penalty associated with operator visibility systems on the Transition is approximately 13 

pounds; exterior lighting adds another 11 pounds for a total ground visibility weight penalty of 24 

pounds.

Enhanced Flight Safety

Ballistic Recovery System

The Transition® incorporates a standard, rocket-deployed ballistic recovery system (BRS, commonly 

referred to as an airframe parachute). The added safety benefit of such as system is self-evident: BRS 

technology has already saved over 300 lives in other types of GA aircraft.
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The weight penalty associated with the incorporation of this important safety technology into the 

Transition® is approximately 36 pounds.

Description of the Exemption Relief Sought 

Unique functionality notwithstanding, the Transition® is compliant with both the spirit of LSA and the 

ASTM standards that apply to them. It is simple to fly, safe, and easy to operate with automated 

conversion between modes. It has a high stability margin, good stall warning characteristics, and 

significant stall margin during takeoff and landing maneuvers. 

Therefore, in order to bring the Transition® to market within the structure of LSA, Terrafugia requests 

relief from the sections of 14 CFR Parts 21, 61, and 43 where light-sport aircraft are referenced such that 

the Transition® may be treated as such for all aspects of airworthiness, operation, flight instruction, and 

maintenance. Specifically, we request:

 Allowance for a maximum takeoff weight of not more than 1,800 pounds; and, 

 Allowance for a maximum stalling speed of not more than 54 knots. 

Suggested conditions and limitations for this requested exemption are as follows:

1. This grant of exemption applies only to the Terrafugia Transition® aircraft.

2. Terrafugia Inc. must supply each purchaser of a Transition® aircraft with a copy of this exemption. 

A copy of the exemption must be carried on board each Transition® aircraft certificated under the 

provisions of this exemption.

3. Terrafugia must maintain a record of all owners of the Transition® aircraft certificated under the 

provisions of this exemption.

Terrafugia believes that this exemption is in line with the original spirit of the light sport rulemaking and 

serves safety, the GA industry, and the public good.

Conclusion 

By allowing the Transition® to come to market as an LSA with the requested vehicle weight and stall speed, 

the FAA has the opportunity to support the future of the personal aviation industry through both an 

increase in safety and a potential reversal in the declining trend of personal aviation. 

It is well known that the pilot population has been shrinking and that we are losing our GA infrastructure 

due to inactivity. This is due in part to obstacles faced by private pilots such as weather sensitivity, high 

costs, long door-to-door travel time, and lack of mobility at their destination30, combined with an aging 

pilot population. From a functional perspective the Transition® addresses all of these obstacles, as the 

user can: 

 Land and drive in the event of inclement weather;

 Store the vehicle at home;

 

30 Downen, Troy D. and Hansman Jr., R. J. “User Survey of Barriers to the Utility of General Aviation”, 

Massachusetts Institute of Technology, 2002-01-1509.
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 Use unleaded automotive gasoline with good fuel economy to reduce fuel costs (and 

environmental impact);

 Reduce the overhead time spent at the airport on both ends of the trip to shorten door-to-door 

travel time;

 Gain mobility at the destination airport (where there is often no convenient ground 

transportation) by being able to fold the wings and drive; and,

 Employ simple LSA operation and easy vehicle entry and egress (which allows for a higher level of 

operational safety and ergonomic convenience with the existing pilot population).

The Transition® is also in line with public expectations of what the future should bring, and is attracting 

new people to aviation. A recently published Pew Research Center and Smithsonian Magazine survey31

indicates that flying cars are the number one answer to the question, “If there was one futuristic invention 

that you could own, what would it be?” The early pre-orders for the Transition® support this as well. 

Perhaps because of the unique functionality combined with the safety features of the Transition®, 

Terrafugia has experienced first-hand the potential for GA market growth: 55% of our existing orders have 

come from outside the existing active pilot community (i.e., pilots who have allowed their currency to 

lapse, student pilots, or people entirely new to personal aviation). Terrafugia’s role as an expansive force 

for personal aviation was also on display at the 2012 New York International Auto Show (NYIAS), where 

tens of thousands of people saw the Transition® and hundreds inquired of our team regarding how to 

become a pilot – realizing for the first time that it was possible for someone to fly themselves 

recreationally or for personal travel.

The Transition® drawing a crowd – and inspiring interest in GA – at the 2012 New York International Auto Show.

The level of interest in flying cars in general and the Transition® in particular should not be surprising given 

the current state of personal transportation in the United States. While the Transition® may have a direct 

impact only on the longest-distance commuters, it increases visibility for personal aviation and serves as 

a proof of process for future innovation that could have even broader benefits.

While industry growth and improvements in personal transportation are both compelling upsides of the 

Transition®, safety is – as always – the most important benefit. As discussed earlier in this document, the 

roadable functionality of the Transition® provides a safety benefit both by reducing the temptation for 

 

31 http://www.pewinternet.org/2014/04/17/us-views-of-technology-and-the-future/
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VFR into IMC, and by adopting many basic techniques for occupant protection from the automotive 

industry. As a result, the Transition® will have a significant crashworthiness increase compared to other 

GA aircraft. Terrafugia is advancing the state of the art in light aircraft crashworthiness with lessons 

learned that are applicable outside of both the LSA and the roadable aircraft niches. The need for this 

work and its broader applicability has been made apparent through Terrafugia’s participation in industry 

symposia,rulemaking, and standards creation activities. Terrafugia has presented on the above-described 

safety systems as part of multiple industry sessions on crashworthiness and GA safety. Lessons learned 

are also being applied to the ASTM F2245 Annex for Roadable Aircraft

32, for which Terrafugia is Technical 

Lead. 

Broader public interest is also served by the success of the Transition® through the positive economic 

impact of an innovative U.S. company creating skilled manufacturing jobs. With the Transition® as a 

“proof of process” product for the emerging flying car and personal aviation industry, eventual economic 

gains could significantly surpass that of the current GA industry in 10 to 20 years – from both a 

manufacturing perspective and by reducing the burden of commuting. More intangible, but important 

nonetheless, is the ability of the Transition® to inspire the innovation economy along with STEM students 

and educators throughout the U.S. and the world.

By allowing the Transition® to come to market within the innovation- and market expansion- friendly 

environment of LSA, the FAA will play a key part in reinvigorating GA while simultaneously realizing 

advances towards its stated goal of doubling the safety of personal aviation while halving the cost of its 

certification. 

 

32 ASTM WK43684 as of the date of this petition.
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Appendix 1: Additional Safety Commitment and Features of the Transition® 

While General Aviation (GA) has made remarkable strides in increasing safety through the prevention of 

accidents, occupant protection in the event of an incident, particularly in light aircraft, remains an area 

for improvement. Regardless of the cause of the accident, injuries and fatalities ultimately result from 

forces experienced by the occupants and their interaction with the cockpit environment. The 

crashworthiness features included in the Transition® decrease the potential for serious injury and death 

in every accident scenario the aircraft might encounter – not only for loss of control events. 

The need for this safety improvement is clear. According to the information presented in the Aircraft 

Owners and Pilots Association (AOPA) Air Safety Institute’s 2009 Nall Report, normalized with fleet 

average cruise speed data, GA saw 128 fatalities per billion miles traveled. By contrast, for this same year, 

ground motor vehicle travel saw 8.3 fatalities per billion miles traveled. This 15-fold difference cannot be 

fully explained by the difference in speeds associated with the two modes of travel, and it could be 

significantly reduced by incorporating into light aircraft some of the technologies that have been proven 

to be effective in reducing automotive fatalities: structural energy absorption, maintenance of a 

survivable volume around the occupants, and occupant protection through restraint and cockpit design. 

These are the same features, among others, that are required by the FMVSS and incorporated into the 

Transition®.

A key component of the Transition® roadable aircraft’s value – and of its increased safety effect on the 

flying public – is the ability to land at an airport, fold its wings, and continue its journey on the ground. In 

addition to offering a previously unavailable level of convenience which is attracting new pilots to personal 

aviation, this capability also contributes significantly to the overall safety of the vehicle. By far the greatest 

source of fatal accidents for fixed-wing GA accidents is pilot-related33 at 71.4% in 2010. Of the weatherrelated accidents that contribute to that number, by far the most significant cause is “VFR into IMC”, or 

flying under Visual Flight Rules into Instrument Meteorological Conditions (i.e. bad weather), which 

accounts for 49% of weather-related accidents. By providing pilots the option of diverting, landing safely, 

and continuing their trip on the road, the Transition® addresses the psychological barriers that cause pilots 

to experience “get-there-itis” and push their flight into potentially dangerous conditions.

In addition to the crashworthiness features discussed at length in the body of this petition, Terrafugia has 

incorporated a number of other safety-specific systems and features into the Transition® aircraft. It 

should be noted that – although not specifically included in our substantiation data – there is a weight 

penalty associated with some of these components as well. 

Stall Warning and Stall Characteristics

The Transition® has been designed to incorporate a novel stall warning and prevention feature that has 

the potential to help reduce stall-spin accident scenarios. Due to the rear wheel location of the 

Transition® being farther aft of the center of gravity (CG) than is typical in other aircraft -- to provide 

stability on the road -- the smoothest landings happen with significant stall margin. Therefore, Transition® 

pilots will tend to fly all segments of the traffic pattern with more power and at slightly higher airspeed, 

 

33 Aircraft Owners and Pilots Association (AOPA) Air Safety Institute 2011 Nall Report
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lower angle of attack, and more stall margin. This fact alone should reduce stall-spin accidents in the 

Transition® as compared to existing LSAs. 

In addition, when a power-on stall is imminent (as could occur during approach to an accelerated stall on 

the turn from base to final), the aerodynamic design of the Transition® guides the separated air through 

the propeller which makes a noticeably different sound, thereby warning the pilot of an imminent stall. 

There is little that is more concerning to a pilot than engine failure, so this new engine noise that arises 

from the flow of separated air through the propeller is a very effective warning, perhaps even more so 

than the audible electric buzzers and stall warning horns that are typical of many GA aircraft. It should be 

noted that there is no actual engine trouble in this situation; the different sound arises due to a different 

load on the engine that comes from the separated air flowing into the propeller. There is also an angleof-attack indicator so the pilot may visually assess stall margin.

Finally, the Transition® was designed to ensure a gradual stall progression from the wing root to the tip, 

thus avoiding a sudden break and allowing the pilot to maintain roll control throughout the nose drop of 

the stall; this safety feature alone has been successfully used as substantiation for exemptions similar in 

scope to what we are requesting. The power-off stall also has a distinct nose bobble with no dramatic 

break. These advantageous stall warning and stall performance characteristics of the Transition® further 

enhance the expected level of safety of the vehicle. The aerodynamic feature that enables these 

characteristics is the boat tail of the fuselage-wing junction. This boat tail required an extended drive 

shaft between the engine and the propeller which also added to the increased weight as quantified in the 

previous section.

Loading Safety

The useful cargo and passenger volume in the Transition® is all located forward of the CG of the vehicle 

– making an aft-CG pilot-load-induced instability practically impossible, as long as the pilot weighs more 

than the minimum allowable pilot weight (which will be included in the POH and is estimated to be less 

than 120 pounds).

Increased Cockpit Visibility and Situational Awareness

The Transition® has outstanding visibility from the cockpit compared to other LSAs due to the position of 

the cabin forward of the main wing. This positioning, combined with extra window and “moon roof” area, 

increases the level of safety when executing turns. In addition, there is an integrated GPS moving map 

with an ADS-B in/out transponder to enhance situational awareness.
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The view from inside the Transition® cockpit provides notably greater visibility than most LSA.

Appendix 2: Discussion of Sport Pilot Flight Operations 

The Transition® was designed from the start to be an easy-to-fly aircraft – in the spirit of the Sport Pilot

Light Sport Aircraft rule. The conversion and driving ability of the Transition® do not add complexity to its 

operations as an airplane (or as a car). The conversion mechanism is automated and operated from inside 

the cockpit: the pilot does not need to perform any mechanical operations to convert from flying to driving 

or vice versa. A standard pre-flight is performed as with all light aircraft following the deployment of the 

wings. In flight, the Transition® is flown with a stick, rudder pedals, and throttle. On the ground, it is 

driven with a conventional steering wheel and gas and brake pedals. 

The longitudinal stability margin is large with an average size pilot at the controls, and very large with two 

people in the cabin. The Transition® has “heavy controls” for an LSA. It is a “cruiser,” not an aerobatic or 

touchy airplane. These characteristics are ideal for the expected operator demographics: it is easy to fly 

and hard to upset.

From a flight operations perspective, the Transition® is as easy as flying gets. There is no retractable gear, 

no airbrakes/spoilers, no variable pitch propeller, no mixture control, no carburetor heat, no cowl flaps, 

and no wing flaps – just stick, rudder pedals, and a single-lever throttle. Due to the reduced control set, 

the Transition® is even simpler to operate than many other LSA.

Terrafugia has had a total of twelve test subjects fly the second-generation Transition® prototype. Five of 

the pilots had over 2,000 hours of flight experience each, five had less than 200 hours, and two were nonpilots. All flights were conducted under the supervision of Terrafugia’s Chief Test Pilot and Director of 

Flight Test Operations, Col. Phil Meteer, acting as Pilot in Command (PIC) and flight instructor. This 

statistically relevant number of test subjects confirmed that the Transition® is easy to learn to fly.

The largest difference between the Transition® and other LSA from an operational perspective is that 

steering on the ground is implemented with a steering wheel instead of a rudder pedal interconnect or 

differential braking. During Transition® training, special attention is paid to takeoff and landing technique, 

which differs somewhat from other aircraft due to the use of the steering wheel on the ground. The use 

of the steering wheel is intuitive, but pilots must be trained to get used to the transition from flight 

controls to ground controls when landing and vice-versa on takeoff. After a few repetitions, proper 

operation becomes habitual, as is the case with transition training for the unique characteristics of any 
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other aircraft. Using a steering wheel for taxiing makes ground handling very simple and intuitive for 

anyone who drives a car.

Due to the location of the rear wheels (further aft of the CG than most other LSAs), the Transition® cannot 

rotate for takeoff until there is more than adequate airspeed for flight. This ensures that by the time the 

vehicle leaves the ground, there is significant extra energy that can be translated to a higher-than-average 

rate of climb near the ground (improving obstacle clearance performance and stall margin on takeoff). 

The downside is a longer-than-typical ground roll; however, this longer ground roll provides a safe and 

effective abort option all the way until lift-off due to the four-wheel stability of the Transition® and 

comparatively powerful brakes. On landing, this configuration significantly reduces the probability that a 

pilot will “bounce” the aircraft back into the air, and the immediate reduction in angle of attack that 

happens on touchdown ensures that the brakes have sufficient weight to be effective and keep landing

rolls very short. 

In summary, Transition® operations are simple and consistent with the capabilities of a sport pilot and 

the intention of the LSA rule.

Appendix 3: Anticipated Transition® Training Program 

Conversion

While the Transition® offers the unique additional functionality of being able to fold its wings and drive 

on surface roads and highways, it remains a simple-to-fly Light Sport Aircraft. The conversion between 

flying and driving modes for the Transition® is comparable to or simpler than the conversion processes 

for folding or removing the wings of other LSAs that are designed to be trailered or stored in a smaller 

volume: 

 Electric actuators provide ease and consistency to the conversion. 

 Redundant latching mechanisms are easily verified during a standard pre-flight inspection and do 

not require the insertion of any additional components to be secure. 

 Innovative cable routing and stick design means that control surfaces remain appropriately 

connected at all times. 

 The aircraft’s on-board computer monitors the entire conversion process to ensure that it is 

completed successfully and only activated when the Transition® is on the ground with the engine 

off. 

Thus, while it will of course be necessary to familiarize pilots with the conversion process for the 

Transition®, this does not pose a risk beyond what is already found in the LSA industry. In fact, Terrafugia’s 

unique folding mechanism directly addresses several known issues seen in other configurations.

Driving

Anyone with a driver’s license will become comfortable driving the Transition® very quickly – within the 

first few minutes of being behind the wheel. The gas pedal, brake pedal, steering wheel, turn signals, 

wiper controls, shifter, etc. are all as one would expect to find them in a car. The continuously variable 

transmission in the vehicle behaves to the operator like a commonly seen automatic transmission with no 
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gear shifting to worry about while driving (other than to shift between forward, neutral, park, and 

reverse). 

Based on experience to-date, it is expected that incorporating a modest amount of driving into the flight 

training program outlined in the following section will be more than sufficient for licensed drivers to 

become comfortable with the vehicle on the road.

Flying

A recent series of two-person flights in the Transition® have confirmed that the aircraft is easy and 

comfortable to fly for a wide variety of experience levels: from non-pilots to experienced test pilots. 

Terrafugia has used this experience and other time spent in the Transition® to create an initial outline of 

a customer flight training program for the vehicle. Current business modeling includes five hours of flight 

training with the purchase of each aircraft, with additional training available.

Customer training plans have been created to cover a wide range of incoming student skill and experience; 

while the length of time spent on each item will vary as needed, the following six lessons are anticipated 

to serve as the basis of the Transition® customer training program:

1. Vehicle introduction and local driving

2. Classroom training

3. Introductory flight

4. Advanced driving

5. Traffic pattern flight and ground operations

a. Includes airport entry and exit

b. Taxiing (done with steering wheel)

6. Advanced drive and flight

a. Multiple airports

b. Evaluation

An optional 14 CFR §61.56 flight review could conclude the training activities.

A three day course would be offered such that items 1, 2, and 3 would be covered on Day 1, items 4 and 

5 on Day 2, and item 6 on Day 3. The feasibility of this approach is supported by our two-person flight 

experience.

To accommodate anticipated increases for demand in training, and to provide a solution for non-pilots 

interested in the Transition® (currently, approximately 25-30% of reservations for the Transition® come 

from non-pilots), Terrafugia plans to partner with existing flight schools. Partner instructors would 

undergo the full training program as described above as well as participate in advanced contingency work 

with Terrafugia’s test pilots.