Frequently Asked Questions

about Experimental Aircraft

EAA Chapter 1373 – Counties of Delta and Montrose on Colorado's western slope

Created:          11 January 2017

Last updated: 24 January 2017



The information below refers to United States Federal Aviation Regulations.

Experimental Aircraft

What is an experimental amateur built aircraft?

In the US, “experimental aircraft” generally refers to an aircraft flown under an experimental category Special Airworthiness Certificate. The aircraft may be based on a well-tested and proven conventional design and therefore not truly experimental. Homebuilt aircraft built from a kit or from scratch fall into this category.

Experimental Amateur Built (EAB) aircraft are those for which the major portion has been fabricated and assembled by a person(s) who undertook the construction process solely for their own education or recreation.

(Ref.: FAA Experimental Category, FAR §21.191, §21.193)

What are some of the more popular aircraft kits available?

Here are some manufacturers of aircraft kits commonly built and flown in this area: Vans, Zenith, Kitfox, RANS, Lancair, Sonex. Each manufacture has several different types available.

Who can maintain or repair my experimental amateur built aircraft?

Anyone. There is no certification required to maintain or repair an EAB aircraft. Literally anyone can perform this work. Naturally, the owner/operator should assure the person making repairs (including him/her self) is competent to do so. (Ref.: §43.1b)

Can I use type-certified aircraft components in my EAB aircraft?

Yes. However, once a type-certified component is installed in an experimental aircraft it is no longer certified. (Ref.: EAA FAQ, FAA AC 39-7D 9b, FAA 8130.H)

What is the “51%” or “major portion” requirement?

This applies to experimental category aircraft as described in the first question above. It simply means that the “major portion of the aircraft has been fabricated and assembled by persons who undertook the construction project solely for their own education or recreation”.

Note that any number or people may work on the aircraft. In some cases, aircraft kits and projects pass through several owners before they are finally finished. This does not violate the major portion rule as long as all builders “undertook the construction project solely for their own education or recreation”. If you purchase an unfinished kit from another party make sure to obtain the construction log to prove the major portion was amateur built.

You may not pay someone to build your EAB aircraft and you may not build an EAB aircraft to sell for profit.

(Note that ELSA are different from EAB aircraft. See LSA section below.)

(Ref.: FAR §21.191, FAA 8130.H)

What does a Condition Inspection involve?

The aircraft’s Operating Limitations describe the requirements for a Condition Inspection. Typically, the OL require the inspector to certify that “this aircraft has been inspected on [date] in accordance with the scope and detail of appendix D part 43, and was found to be in a condition safe for operation”. Per the OL, a condition inspection is required every 12 months.

Note that although part 43 (§43.1b1) specifically states “This part does not apply to— Any aircraft for which the FAA has issued an experimental certificate[…]”, in this case the Operating Limitations override this and the condition inspection must be completed in accordance with Appendix D. Also, note the inspector is certifying the aircraft is “safe for operation”. He is not saying it is airworthy.

Who can complete a condition inspection on my EAB aircraft?

The primary builder who holds a Repairman certificate for the aircraft, or a certified A&P mechanic can complete the condition inspection.

The primary builder may obtain a Repairman certificate to perform condition inspections on the EAB aircraft he/she constructed in accordance with the operating limitations of that aircraft. (Ref.: FAR §65.104)


There can be only one primary builder. Therefore, if you purchase a completed EAB aircraft you cannot obtain a Repairman certificate for that aircraft and you cannot perform a condition inspection of it. (There is no class or certification that will allow you to do this, other than as a certified A&P mechanic. Note that ELSA are different in this respect; see below.)

Any certified A&P mechanic may complete a condition inspection on an EAB aircraft. The mechanic does not need to hold an Inspection Authorization (IA) certificate.

How is a condition inspection different from the annual inspection for a type-certified aircraft?

The condition inspection:

·         May be completed by the primary builder (if he/she registered the aircraft and obtained the repairman certificate for that aircraft).

·         May be completed by an A&P mechanic (an IA is not required).

·         Is not required to follow an inspection checklist.  (There may be none, unless the original builder created one.)


Must my EAB aircraft comply with airworthiness directives (ADs)?

Yes! (if the AD itself states that it applies).

Advisory Circular 39-7D (section 9b) addresses this directly: “Unless stated otherwise (see subparagraph 9b of this AC), ADs only apply to type-certificated (TC) aircraft, including ADs issued for an engine, propeller, and appliance.” Subparagraph 9b states “The AD applicability statement will identify if the AD applies to non-TC’d aircraft or engines, propellers, and appliances installed thereon.” Section 9b goes on to include examples of ADs that would apply to all aircraft, including non-type certified aircraft. If the AD states “This AD applies to any aircraft […]”, then it applies to EAB aircraft and components.

More detail, and a counter argument:

There may be, however, a valid argument that ADs do not apply to EAB aircraft. The examples shown in AC 39-7D 9b do not explicitly state that they apply to non-TC’d aircraft (as described at the beginning of section 9). Plus, ACs are not binding.

Some time ago – exact date unknown – the EAA stated “EAA takes the general position that AD’s do not apply to experimental amateur-built aircraft or to any previously type certified parts being operated on an experimental amateur-built aircraft.” The EAA no longer publishes this or other position papers but the original article can still be found here and here. The EAA’s reasons for this position were:

·         The aircraft has no type design, nor do any of the design standards in the FAR’s apply (e.g. Part 23)

·         FAR Part 43 Maintenance, Preventive Maintenance, Rebuilding, and Alteration does not apply. [Ref.: §43.1b]

·         FAR 39 Airworthiness Directives, does not apply.

·         The airworthiness standard for experimental aircraft is “safe to fly” not “Conformity to a type design.”

Bottom line:

ADs are published for good reason. Do not ignore them! As an EAB owner/operator, you must decide whether to comply with ADs that may apply to your aircraft. If you do not, and your aircraft is in an accident, you may have a tough time defending that decision to both the FAA and your insurance provider.

Where can I find a POH for my EAB aircraft?

The Pilot’s Operating Handbook is developed by the manufacturer. For an EAB aircraft, the manufacturer is the builder. For example, if John J. Doe builds a Zenith 701 from the Zenith kit the aircraft registration will indicate the manufacturer is “DOE JOHN J”, not Zenith. Thus, John is responsible for creating the POH, although the FAA does not require that he does so.

Can I fly my EAB aircraft at night? In IMC? For hire?

The aircraft Operating Limitations govern operation of the aircraft. For EAB aircraft, the Operating Limitations are attached to the airworthiness certificate and must be accessible to the pilot. (Ref. FAR §91.319)

Can I train for my private or sport pilot certificate in an EAB aircraft?

Yes, you may receive training in an EAB aircraft that you own. There are restrictions around this. You cannot pay another owner to rent their EAB aircraft for any reason. Some instructors hold Letters of Deviation Authority (LODA) from the FAA, authorizing them to operate their experimental aircraft for hire for the purposes of type-specific training. (Ref. FAR §91.319, EAA article)

Light Sport Aircraft

What are the differences between Special LSA, Experimental LSA, and Experimental Amateur Built?

A light-sport aircraft (LSA) is any aircraft that meets the FAA’s LSA definition, whether certificated or experimental. (see Glossary of Acronyms below)

 Any pilot with a Sport Pilot or higher certificate can fly LSA.

Special light-sport aircraft (SLSA) are factory built aircraft constructed to an industry consensus standard and sold with a special airworthiness certification.

Experimental light-sport aircraft (ELSA) are assembled from a kit under the experimental rules. The company providing the kit must have produced and certified at least one SLSA to be permitted to sell ELSA kits of the same model.

Note: ELSA is not the same as EAB! Even though many EAB aircraft qualify as light sport, they are not ELSA. Here are some important differences:

·         ELSA kits are not subject to the “major portion” rule (FAR §21.191g) that EAB aircraft are. You can pay someone to build some or all of your ESLA for you.

·         ESLA must follow the exact manufacturer design and specifications. The builder cannot choose an engine model, propeller, or other part different from that specified by the manufacturer. Builders of EAB aircraft can modify their design at will.

The Van’s RV-12 provides an illustrative example of these differences, because the same model can be licensed in three ways:

·         As SLSA: You can purchase a fully complete, factory built RV-12 from a Van’s Aircraft dealer. SLSA may be used as a rental, for paid instruction, or for commercial purposes.

·         As ELSA: You can purchase an RV-12 kit from Van’s and either build it yourself or pay someone else to complete it. It must be built to the exact specifications provided by Van’s. An ELSA owner can take a 16-hour class and receive a Repairman certificate that allows them to conduct the annual condition inspection themselves. (FAA AC65-32A)

·         As EAB: You can purchase an RV-12 kit from Van’s and build it to any specification you prefer. Unless you dramatically change the design, it will still qualify as LSA. (Van’s does not recommend changing their design or parts selection.) The primary builder of EAB aircraft may complete the annual condition inspection, but any subsequent owners must have an A&P mechanic do this.

Owners of SLSA are permitted to “downgrade” their aircraft to ELSA. By doing so, they lose commercial use of the aircraft, but they gain the ability repair and maintain the aircraft or even change the design however they desire (as long as it stays within the LSA definition).

Here are some links to good articles on this topic: Kitplanes magazine, Airtime Aircraft, Aviators Hotline.

(Ref.: FAR §1.1,  ATSM Committee F37 on LSA, )

Certifications and Medical Requirements

What are the requirements to fly as a Sport Pilot?

See FAR Part 61 Subpart J—Sport Pilots.

I'm a certificated pilot without a medical. Can I fly as a sport pilot?

Yes. For example, let’s say you are a certified Private Pilot but you stopped flying 15 years ago and your medical certificate is not current. You can fly as a Sport Pilot if you have a valid driver’s license (and you meet other Sport Pilot requirements). Because a PPL is a higher level of certificate than Sport Pilot you do not need to take a written or flight test, although you will need a flight review (f.k.a. BFR).  (Ref.: AOPA FAQ)

My medical certificate application was denied, or my certificate was suspended or revoked. Can I fly as a Sport Pilot?

No. Under current regulations, if you apply for a medical certificate and it is denied you cannot fly any aircraft (perhaps ever). The same is true if your medical certificate is suspended or revoked. Note that if you voluntarily surrender your medical certificate it is considered revoked and you won’t be flying again. (Ref.: FAR §61.2(a))

What’s all this I hear about medical reform?

“The FAA Extension, Safety, and Security Act of 2016 was signed into law on July 15, 2016 and the FAA has named the new rules BasicMed and set May 1, 2017 as the day the regulations will be effective.” –AOPA FAQ

AOPA and EAA both have some excellent FAQs which should answer most questions.


Is my EAB aircraft required to have ADS-B Out by the 2020 mandate?

The ADS-B requirement applies to all aircraft, not just certain types. The ADS-B Out rule starts January 1, 2020. After that, if you stay below 10,000 feet MSL or 2,500 feet AGL (whichever is greater) and out of class B and C airspace you won’t need ADS-B (though this severely limits your flying area). There are additional restrictions and exceptions. See FAA ADS-B FAQ. (Ref.: FAR §91.225)

How can I display ADS-B traffic and weather on my iPad?

Various devices are available that receive ADS-B In data for display on an iPad or Android tablet device. Examples include the Stratus 2S and Garmin GDL. Stratux is a homebuilt ADS-B In receiver that is simple to build and costs less than $150.

Can I buy or build a portable ADS-B Out device to meet the 2020 mandate?

No. While it is technically feasible, use of a portable ADS-B Out device is prohibited by the FAA.



Glossary of Acronyms


A&P                 Airframe and Power plant – Generally refers to an aircraft mechanic who is certified to work on both the power plant (engine) and the airframe for aircraft. (Ref.: FAR §65.85, §65.87)

AC                    Advisory Circular – The FAA issues advisory circulars to inform the aviation public of non-regulatory material. Unless incorporated into a regulation by reference, the contents of an advisory circular are not binding on the public.

AD                   Airworthiness Directive – The FAA issues airworthiness directives in response to deficiencies or unsafe conditions found in aircraft, engines, propellers, or other aircraft parts. ADs must be followed to remain in compliance with the FAA. (Ref.: FAR §39.7) (See also the question above regarding applicability of ADs to experimental aircraft and parts.)

ADS-B              Automatic Dependent Surveillance-Broadcast – A surveillance technology in which an aircraft determines its position via satellite navigation and periodically broadcasts it, enabling it to be tracked. (Ref. Wikipedia)

AIM                 Aeronautical Information Manual – Official guide to basic flight information. (Ref. FAA PDF)

AOPA               Aircraft Owners and Pilots Association

AVT                  Aviation Maintenance Technician

BFR                  Biennial Flight Review – All certificated pilots must complete a Flight Review (formerly known as a biennial flight review) every 24 months. (Ref.: FAR §61.56)

CFR                  Code of Federal Regulations (also e-CFR for “electronic” CFR)

DAR                 Designated Airworthiness Representative – An individual designated by the FAA to act on its behalf in the certification of type-certificated and amateur-built aircraft for the issuance of airworthiness certificates, special flight permits, import aircraft, export certificates for products and articles, conformity inspections and field approvals for repair and alterations. (Ref. Wikipedia)

DPE                  Designate Pilot Examiner – A person designated by the FAA to conduct the practical test (checkride).

EAA                  Experimental Aircraft Association

EAB                  Experimental Amateur Built

EFB                  Electronic Flight Bag – Instrument (such as a tablet or smartphone) that manages pilot information electronically. This could include charts, location, flight plans, weather reports, aircraft documents, and other information. Examples include ForeFlight and Garmin Pilot running on an Apple iPad.

EFIS                  Electronic Flight Information System – Electronic instrument that displays attitude, airspeed, altitude, turn rate, time, or other information.

EMS                 Engine Monitoring System – Electronic instrument that monitors and displays engine information such as: fuel level and burn rate, RPM, manifold pressure, cylinder hear temps, oil temp and pressure, amperage, voltage, exhaust gas temps, and other information.

ESLA                Experimental Light Sport Aircraft – A kit version of a SLSA. (Ref.: Sport Aviation Specialties)

FAR                  Federal Aviation Regulations – See e-CFT link to FAR

FSDO               Flight Standards District Office – FSDO is a locally affiliated field office of the FAA. Delta and Montrose counties in Colorado are serviced by the Utah FSDO in Salt Lake City. (Ref. FAA website)

GPS                  Global Positioning System – Often GPS refers to a device capable of receiving information from a global navigation satellite system.

IA                     Inspection Authority – Generally refers to an A&P mechanic who is certified to perform inspections. (Ref.: FAR §65.91)

ICAO                International Civil Aviation Organization – A UN specialized agency established to manage the administration and governance of international air navigation.

LODA               Letter Of Deviation Authority

LSA                  Light-Sport Aircraft – An aircraft, other than a helicopter or powered-lift that, since its original certification, has continued to meet the criteria for same – max takeoff weight 1320 pounds, max airspeed 120 knots CAS, max two place, etc. Any aircraft that meets the LSA definition can be flown by Sport Pilots (or those with a higher rating) with the appropriate endorsements. (Ref.: FAR §1.1)

LSRM               Light-Sport Repairman – Maintenance

OL                    Operating Limitations

POH                 Pilot’s Operating Handbook – This is essentially the “owner’s manual” for the airplane.

PPL                  Private Pilot License – There is no such distinction in the US FAR. Informally, this term is synonymous with “private pilot certificate”. (Ref.: FAR §61.113, Wikipedia)

SLSA                 Special Light Sport Aircraft – An aircraft that meets LSA specifications. (Ref.: Sport Aviation Specialties)

STOL                Short TakeOff and Landing

WAAS              Wide Area Augmentation System – This … (Ref.: Wikipedia)


For more definitions, see Part 1 of the Federal Aviation Regulations, including §1.1 General definitions and §1.2 Abbreviations and symbols.