Changing the Propeller, Can I Add Seats?

Ask the DAR.


Question: I am upgrading the propeller on my aircraft and was wondering if you might be able to help me out. My situation is as follows: I bought my aircraft from an estate as the builder has passed away. The aircraft was certified in 1999, which makes it 20 years old, the propeller is the original Aymar-Demuth, which is showing some signs of age, and I would like to update it. As Aymar-Demuth is now out of business, I have opted to go with a WhirlWind.

According to your previous guidance on similar cases, I understand that I am allowed to do all the work myself installing it and writing in the log, but the aircraft will need a new weight and balance. And I will have to fly off a 5-hour Phase I test.

But you’ve also said that “If the airplane is more than 11 years old, your operating limitations may require a recurrent airworthiness certification.” How do I find out if I need to do this? And how do I go about doing that? Also I am under the impression I need to write to my FSDO and request a box for testing? Same thing here, can I just email them something like this modified for my location?

Answer: Yes, you are correct in that you may perform any and all work on your Experimental/Amateur-Built aircraft.  The only thing you cannot do is to perform the Annual Condition Inspection. That must be done by the original builder, if he/she holds the repairman certificate for that aircraft, or a certified A&P mechanic.

To determine the requirements on changing the prop, check your operating limitations. The operating limitations have changed over the years, and you must abide by the ones issued to your aircraft.  If they are of an older revision, you may have them amended to the latest by your local FSDO or a DAR.

Depending on your operating limitations, the FSDO may or may not require notification in writing.  Give them a call and have your ops limits in front of you so that you can read them to the inspector.

Question: I’m considering purchasing a Jabiru J230/J250 in the SLSA category, but I very much would like to install back seats in it like the J430/J450, and increase its gross weight. These are the same airframes, just less the back seat. How do I go about changing the category/class for this to legally fly it with more than two people on board? Or is it even possible?

Answer: Thanks for your question.  Unfortunately, you’re not going to like my answer.  Aircraft built in accordance with FAR Part 21.190 (SLSA) do not qualify under any other category except for 21.191(i)(3), which is downgrading the aircraft to the Experimental Light-Sport category.  And of course, installing two more seats would not meet anything in the Light-Sport category.

The only possible way to do this would be under the Experimental Exhibition under FAR Part 21.191(d). And this is not one of my favorite categories. It is quite restricted and not really intended for this type of operation.


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