CG Limits

[Danzer1]

Skot,

You have a couple of issues to deal with.

1st, if I recall, you bought the aircraft used. Did you ever obtain a repairmans certificate for it? If so, you can sign off on the changes. If not you will need an AP to sign off. Once you have that sorted out -

2nd, you need to read the operating limitations in your Airworthiness Certificate. Likely it is worded ambiguously enough to prompt a call to your local FSDO for clarification.

If they consider the changes substantial enough (likely) they will also (likely) require a new condition inspection and a new phase one flight testing for a certain number of hours. With a new condition inspection a new weight and balance could be required.

Changing an engine (even of same type) and adding accessories that weren't there before - will (likely) prompt any FSDO to require the above, but as we know, they all don't all interpret what is written the same, so it is best to check with them first.

Greg

[N981MS]

Skot,
As I understand it, anyone can work on an experimental. Change the engine to a turboprop. Wing airfoil. Make it a biplane. Put in a heater. Anything. No need for an A&P sign off.

The repairman's certificate allows the builder to do the annual condition inspection.

Crazy eh?

I do not think your weight and balance issues require FSDO involvement unless you are changing the current registered cg range. If you are just updating your empty weight and empty cg, I think you are OK.

At least one DAR I know says things that change flight characteristics are what requires going back in to phase one for a duration determined by the FSDO. ie change the prop. Change Engine type. Change gross weight.

I am not a DAR and did not stay at a Holiday Inn last night so YMMV.

[Danzer1]

Max,

As I understand it, anyone can work on an experimental. Change the engine to a turboprop. Wing airfoil. Make it a biplane. Put in a heater. Anything. No need for an A&P sign off.

The repairman's certificate allows the builder to do the annual condition inspection.

For clarity - I did not say he couldn't do the work himself - I was intending to refer to signing off the annual condition inspection as you have mentioned.

If he does not have the repairmans certificate - he then needs an A&P to sign off on the annual and that would include all changes made since the last annual. The conditions of the airworthiness certificate usually mention logging modifications and I would expect any good A&P to notice the changes made in review of the logs and therefore include them in the annual inspection.

At least one DAR I know says things that change flight characteristics are what requires going back in to phase one for a duration determined by the FSDO. ie change the prop. Change Engine type. Change gross weight.

I agree, so the question would be for the DAR/FSDO - does adding an oil cooler, thermostats, cabin heater, piping, fan, etc - change the CG and the gross weight and distribution and hence flight characteristics? Would be up to his local DAR/FSDO to clarify - as mentioned.

Skott also mentioned in previous threads/posts, adding strut fairings, fuel pump, new prop blades, replacing engine and mount. So again, up to the DAR/FSDO as to whether any of this would change not only the weight, but also the flight characteristics of the aircraft.

Still think it's best to check (FWIW).

Greg

[jrevens]

I know that practically everyone reading this knows that if it's licensed as experimental amateur-built (EAB), you can't get a Repairman's Certificate unless you're the builder.

If you bought the airplane, it would be a good idea for your own peace of mind & safety to do a weight & balance computation regardless of any changes, and especially if doing something like an engine change, IMHO. The small amount of time & effort is worthwhile.

[SWeidemann]

Guys,

For a local opinion from an experienced builder friend of mine, who is also a long time EAA Chapter Technical Counselor for two chapters, I called him today.

I'm going with his advice that new inspections by the Feds followed by designated flight testing would only be prudent for major changes that will affect the flight characteristics. Small changes that change or add (small) weight distribution should be recorded as far as what they weigh, where the changes are in the airframe, and be included in a re-done weight and balance, or better yet, an actual re-weighing to figure the flight range. A new engine, same model as the one removed has no significance.

So far the only change (for weight & balance) I have made is the cabin heater kit. I will probably add the thermostats as well. My friend has a set of scales, so I may be re-weighing as well.

Since this EAB plane was built by another, I will be getting my Condition Inspection (not an Annual) by my regular mechanic. He is aware of what I am doing. If I had a ELSA I would be taking the Rainbow repairman's certificate class. If I built a kit or something with the 51% rule I would certainly apply for my repairman's certificate for that aircraft.

Skot

[Paul Z]

An interesting article on changing from an SLSA to ESLA.
Definitely some advantages to going ESLA. I have considered doing this with my plane.

http://www.newplane.com/amd_download...0to%20ELSA.pdf

[SWeidemann]

Paul,

As the current rules stand, you could convert your Kitfox SLSA to the ELSA category, take a two day maintenance course, and then be qualified to legally maintain your plane (and sign off the annual condition inspections). Sounds wonderful to me, however I would want to follow up what (if anything) is happening with the Craig Holmes FAA draft proposing restrictions. I have found old information about these ideas to change the regulations (from around March, 2014), but nothing since.

Skot