Ask the DAR

Modifying different types of Light Sport Aircraft, updating Phase II operating limitations.


Question: Suppose I were to purchase a completed Light Sport Aircraft powered by a Rotax 912 ULS engine and wanted to replace the Bing carburetors with a fuel-injection system (Edge Performance or AeroConversions). If the aircraft had been licensed in the E/A-B category by another person, would I be able to perform the modification myself, or would the work have to be performed (or at least supervised and signed off) either by a licensed A&P or by the original builder who holds the repairman certificate for that particular aircraft?

If the aircraft was built and registered as an E-LSA, I think I understand that the builder was not permitted to deviate from the design during construction, but can the aircraft be modified after it has been completed and registered? If so, by whom? Same questions for a factory-built S-LSA: Who can approve or perform modifications, if any, on an S-LSA?

Answer: First, anyone can modify and/or maintain an aircraft certificated in the Experimental/Amateur-Built category. You do not need to be an A&P or the original holder of the repairman certificate to sign off on anything except for the annual condition inspection.

Now for an Experimental Light Sport Aircraft: After certification, the same rules apply as for E/A-B except that any modification may not take the aircraft outside of LSA parameters such as gross weight, top speed, stall speed, etc. If the mod takes the aircraft outside of LSA parameters, the airworthiness certificate becomes invalid, and there is no path to return the aircraft to a Light Sport category.

Last but certainly not least, a Special Light Sport Aircraft may not be modified without written consent from the aircraft manufacturer. The alternative here is that you may have the aircraft converted to Experimental Light Sport. This can be done by your local FSDO or a qualified DAR. After that, you may do modifications as in the paragraph above.

Question: I bought an RV-8 four years ago and absolutely love the airplane. After reading something on the Van’s forums, I checked my ops limits and realized that Phase II limitations include the Phase I paragraph stating “This aircraft is prohibited from aerobatic flight…” Many years ago, I was a T-37 instructor, and when I bought the RV-8, I thought I was legal to fly aerobatics and have been doing so.

I live just south of the Atlanta Hartsfield Airport, so the FSDO is close. I’ve printed copies of a new 8130-6 (haven’t filled it out yet), registration, airworthiness certificate, ops limits, and logbook page showing the most recent condition inspection. However, I’m not exactly sure how to proceed.

Answer: Your operating limitations may be amended by a DAR or your local FSDO. You will need to submit a new program letter and a new 8130-6 airworthiness application. The process is pretty simple. If you purchased the aircraft from another part of the country, you probably want to change your Phase I flight test area too. Even though the aircraft is not in Phase I at this time, you may, at some time in the future, make a modification that requires placing the aircraft back into Phase I for flight testing.

Please send your questions for DAR Asberry to [email protected] with “Ask the DAR” in the subject line.

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Mel Asberry
Mel Asberry is an experienced Designated Airworthiness Representative specializing in Experimental/Amateur-Built aircraft. He and his wife, Ann, have built seven amateur-built airplanes including two ultralight types, a Moni Motorglider, a Dragonfly Mk2, two RV-6s and a Zenair CH 601HDS. They are currently building a scratch-built biplane.


  1. is it possible to change the registration from Experimental Light Sport to Special Light Sport registration?
    The aircraft is a 2007 Lambada. Lambadas were imported from the Czech Republic in both configurations and were identical. no changes have been made to the aircraft.
    thank you


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