Ask the DAR

Changing aircraft model type and how DARs set operating limitations.


Question: I am finishing up a major mod to my RV-6A. I have removed the rotary engine and installed an O-360 and a Hartzell B/A prop. Along with this conversion, I also converted to a tailwheel. My operating limitations state that I must fill out an 8130-6 to update the FAA file. Silly question—do I need to change the model to an RV-6 on the 8130, or must I leave it as originally registered?

Answer: It is not mandatory to change the model. An Amateur-Built aircraft model is whatever the builder wishes to call it. To change the model, you would need to install another data plate in addition to the original. The aircraft would have two data plates: one with the original model and another to indicate the new model.

The new data plate must be attached as close as physically possible to the existing data plate without obscuring it. The original data plate must not be altered in any manner.

The normal procedures, including any applicable inspections, apply when processing FAA Form 8130-6. If ownership of the aircraft has not changed, an application for aircraft registration, reflecting the new model designation, need not be submitted. The FAA Aircraft Registration Branch (AFS-750) will issue an amended registration certificate.

You will need to apply for an amended airworthiness certificate.

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Question: How does the DAR generate your operating limitations. Does he make them up from scratch? Are there certain ones he must issue? Can he add others, and why? Can he omit standard ones?

Answer: The “standard” operating limitations for Amateur-Built and Light-Sport Aircraft are listed in FAA Order 8130.2G. They are very specific for Phase I and Phase II operations.

The inspector, be it FAA or DAR, must use them as stated. No items may be omitted. However the inspector may add to the limitations if he/she feels it is necessary for safety reasons.

The inspector will normally issue Phase I and Phase II limitations within the same document, allowing the test pilot to sign off Phase I after completion of flight testing and the minimum number of hours required. However, he/she may decide to issue Phase I only and require another inspection before Phase II operations. When this is done, it is common to have a one-year expiration on the airworthiness certificate.

One common situation is if the aircraft has a pressurized cabin, the inspector may require another inspection after interior installation, pressurization testing, painting, and a new weight and balance. The main reason for testing pressurization after interior installation is to make sure that the pressure vessel has not been compromised during interior installation.

Another common reason for issuing this way is that the inspector may not be totally comfortable with a particular alternative engine installation.

Also remember that Phase I flight test time is listed as “minimum hours”. Normally, it will be 25 hours for a certificated engine/propeller combination or 40 hours for a non-certificated combination. But the inspector may give a longer Phase I if he/she thinks a longer period is necessary. I might also mention that any modification to a certificated engine or prop will void that certification. This can be anything, including aftermarket ignition and/or fuel injection systems.

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

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.


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