Changing an E-AB after certification

[moparrob66]

When your experimental, amateur built aircraft is inspected and registered with FAA as an experimental, what obligation does one have to inform the FAA of a significant modification? If its all kit parts when certified, does replacing, say, the wings with certified Cessna wings, require updating the FAA?

If I build it and register it with one engine and decide to make it a twin, do I need to update the FAA?

I see lots of certified aircraft that become too expensive to keep or make airworthy in accordance with FAA regs, and I understand that its generally frowned upon to make an E-AB from certified parts. Some of these parts planes could be used as good upgrades to a registered E-AB as long as theres no rule or interpretation against it.

 

[Capt. Geoffrey Thorpe]

Your operating limitations will spell that out - the details have varied over time.

But, in general, a major modification will require going back to phase 1 and may require that you notify the FAA.

 

[brcase]

Back about 1976 when my E-AB Glider was changed from V tail to a T-tail it required a new fly off. I would expect anything that significantly might change the handling of the airplane is going to require a new fly off period.

Brian

 

[Salty]

An engine change, especially single to twin is certainly going to require retesting. I would imagine a wing swap would as well.

 

[Dana]

The precise details vary depending on the vintage of the operating limitations. Older ones often say, "any major change invalidates the airworthiness certificate.". Later ones don't invalidate the AWC, but require the FSDO be notified, and in some cases their approval of a new test area. Usually 5 hours is the retesting period. Note that the phase 1 test area is defined in the op lims, so if you're a later owner living in a different place you have to get the operating limitations updated, which means applying for a new AWC.

 

[moparrob66]

Good info thanks! I need to become more familiar with the registration process and the FARs before i craft a certified parts workaround.

 

[Bell206]

before i craft a certified parts workaround.

Just keep in mind the 51% rule is still in play with any workaround. Why not take a certified wing or even aircraft, disassemble it, scan it, 3D print an exact copy of the parts, then reassemble it? I've often heard in aircraft cost discussions the main reason there is not an affordable new small aircraft was the regulatory cost and antiquated production processes. So why hasn't anyone tried to build a Cessna or Bonanza copy under E/AB and use 3D printing or other more modern production methods?

 

[moparrob66]

I think thats an excellent idea, and technology keeps trickling down to the hobbyist level to make it more widely attainable. I imagine certified stuff could be scanned, copied, tweaked as necessary and then 3D models printed, either as ready to use parts or even foam forms to be overlaid with carbon fiber. A lot is possible, so long as the Cancer that is government regulation doesnt stifle it.

 

[Bell206]

A lot is possible, so long as the Cancer that is government regulation doesnt stifle it.

Call it what you want, but the rules haven't changed much in the past 40+years when it comes to designing/building your own E/AB aircraft. So there's been nothing holding you or anyone back. A lot of people went this route copying the Piper Cub series and I believe someone in Canada copied a C180. Often wondered why no one did the same for a Piper Arrow or similar aircraft on a large scale??

 

[moparrob66]

Bushliner Cyclone is awesome, arguably better than its certified Cessna muse, but still ridonkulously expensive at $310k without an engine and an optimistic 1500 hours of assembly. I think theres a lot of room for improvement.

 

[Racerx]

Just keep in mind the 51% rule is still in play with any workaround. Why not take a certified wing or even aircraft, disassemble it, scan it, 3D print an exact copy of the parts, then reassemble it? I've often heard in aircraft cost discussions the main reason there is not an affordable new small aircraft was the regulatory cost and antiquated production processes. So why hasn't anyone tried to build a Cessna or Bonanza copy under E/AB and use 3D printing or other more modern production methods?

I thought that would have been a route for the Mooney folks. Sell kits. Wasn't there a South African Comanche clone?

 

[moparrob66]

I emailed David Maytag suggesting the Helio Courier be reintroduced as a kit, but he never got back to me....

 

[Bell206]

I think theres a lot of room for improvement.

I think based on your previous comments the only way you'll see the "improvement" you are looking for is if you attempt this project yourself. And I'd be willing to bet if you keep this as an open source project there are enough engineers, mechanics, E/AB builders, etc., on PoA who would be happy to give you the technical input to make it happen?? Think of knowledge you will gain from the experience? But every project needs a manager, so when do you start?

I thought that would have been a route for the Mooney folks. Sell kits. Wasn't there a South African Comanche clone?

No idea. I never really got deep into E/AB. However, for the past several years have been "brushing" up on it as a couple friends asked me to look into a new E/AB turbine helicopter venture out of the UK.

 

[Salty]

Just keep in mind the 51% rule is still in play with any workaround. Why not take a certified wing or even aircraft, disassemble it, scan it, 3D print an exact copy of the parts, then reassemble it? I've often heard in aircraft cost discussions the main reason there is not an affordable new small aircraft was the regulatory cost and antiquated production processes. So why hasn't anyone tried to build a Cessna or Bonanza copy under E/AB and use 3D printing or other more modern production methods?

I believe the cost of that would be astronomical if proper materials are used.

 

[Capt. Geoffrey Thorpe]

So why hasn't anyone tried to build a Cessna or Bonanza copy under E/AB and use 3D printing or other more modern production methods?

What would be the point?

If you want to build using things like additive manufacturing, CNC machining, etc. it would only make sense if you designed with the manufacturing processes in mind. Otherwise you are driving drywall screws with a hammer.

 

[kyleb]

Call it what you want, but the rules haven't changed much in the past 40+years when it comes to designing/building your own E/AB aircraft. So there's been nothing holding you or anyone back. A lot of people went this route copying the Piper Cub series and I believe someone in Canada copied a C180. Often wondered why no one did the same for a Piper Arrow or similar aircraft on a large scale??

Build an RV-10. Trade the cost and maintenance of retracts for the expense of 2 more cylinders. Go faster, carry more...

 

[Bell206]

I believe the cost of that would be astronomical if proper materials are used.

If you want to build using things like additive manufacturing, CNC machining, etc. it would only make sense if you designed with the manufacturing processes in mind.

Build an RV-10. Trade the cost and maintenance of retracts for the expense of 2 more cylinders

All good points. Just curious why someone hasnt pursued a similar direction on the E/AB side given the level of technologies available at the grass roots levels now. And while pounding 10 million rivets to build an RV10 or C182 is still a good way to build an aircraft, there seems to be a growing concensous high-tech polymers and composites are the future. At least from what I've seen on the fringes of the industry.

 

[Capt. Geoffrey Thorpe]

HP-24 kit

 

[Dana]

Call it what you want, but the rules haven't changed much in the past 40+years when it comes to designing/building your own E/AB aircraft. So there's been nothing holding you or anyone back. A lot of people went this route copying the Piper Cub series and I believe someone in Canada copied a C180. Often wondered why no one did the same for a Piper Arrow or similar aircraft on a large scale??

Because people building E-ABs mostly want fun airplanes, not antiquated Cherokee derivatives. Cubs and C-180s may be antiquated too, but they're used to do fun things.

 

[kyleb]

... there seems to be a growing concensous high-tech polymers and composites are the future. At least from what I've seen on the fringes of the industry.

The challenge is that composites require a big up-front investment in molds and the like. The DarkAero guys are taking that approach. It'll be interesting to see how their kit pricing compares to sorta similar RV's. Of course, to your point, one might spend more $$ on the DarkAero but save a bunch of time.

 

[Bell206]

HP-24 kit

Because people building E-ABs mostly want fun airplanes, not antiquated Cherokee derivatives.

The challenge is that composites require a big up-front investment in molds and the like.

Okay. So if a person were to offer a true 4-place aircraft with book performance and capabilities, built with the latest technologies and production methods, that meets ASTM or Part 23 requirements, at half the cost of a new legacy aircraft, and qualifies as an E/AB, is it your collective belief this venture would fail in the US market?

 

[kyleb]

Okay. So if a person were to offer a true 4-place aircraft with book performance and capabilities, built with the latest technologies and production methods, that meets ASTM or Part 23 requirements, at half the cost of a new legacy aircraft, and qualifies as an E/AB, is it your collective belief this venture would fail in the US market?

You wanna buy my RV-10 for half the cost of a new SR-22? I promise I used the latest, greatest technologies and <garage> production methods.

This is the true test. ;-)

 

[Bell206]

You wanna buy my RV-10 for half the cost of a new SR-22? I promise I used the latest, greatest technologies and <garage> production methods. This is the true test. ;-)

Ha. I’ll pass since the last I checked an RV-10 didn’t meet Part 23 or ASTM requirements. But the true test is if you’d buy a brand-new SR22 E/AB clone for equal or less than you have invested in your RV-10.

 

[kyleb]

Ha. I’ll pass since the last I checked an RV-10 didn’t meet Part 23 or ASTM requirements. But the true test is if you’d buy a brand-new SR22 E/AB clone for equal or less than you have invested in your RV-10.

I built my -10 before things got insanely expensive. So, yeah, I'd buy an SR-22X clone for that. So would everyone else on the forum. You want the skies filled with airplanes again, make new $160K SR22's happen...

 

[Bell206]

I built my -10 before things got insanely expensive. So, yeah, I'd buy an SR-22X clone for that. So would everyone else on the forum. You want the skies filled with airplanes again, make new $160K SR22's happen...

Does that 160 include your time and labor? Everybody’s time has a value. Would you still buy one for $250K and 3 weeks of your time in a factory setting?

 

[kyleb]

Does that 160 include your time and labor? Everybody’s time has a value. Would you still buy one for $250K and 3 weeks of your time in a factory setting?

That would be a heck of a deal for anyone. 'Course, you've gotta have $250K and 3 weeks of vacation to work with.

 

[Racerx]

Okay. So if a person were to offer a true 4-place aircraft with book performance and capabilities, built with the latest technologies and production methods, that meets ASTM or Part 23 requirements, at half the cost of a new legacy aircraft, and qualifies as an E/AB, is it your collective belief this venture would fail in the US market?

The Ravin 500 is based on the design of the piper comanche, but rendered in composite materials and scaled down some 6–7%

I don't believe it's around anymore.

 

[Daleandee]

'Course, you've gotta have $250K and 3 weeks of vacation to work with.

I have the three weeks. It's the other I'm a bit short on ...

 

[Bell206]

I have the three weeks. It's the other I'm a bit short on ...

Out of curiosity, could you build an RV-10 for less than $250K?

 

[Capt. Geoffrey Thorpe]

If you are building a quickish build kit with a factory new engine and all the bells and whistles to "save money" you aren't going to save money.

Starting with flat stock / tubing, scrounged parts, a runout engine, doing your own overhaul, carve your own prop, etc. you could save money but you have to be pretty dedicated to getting it built.

Unless building an airplane is your actual hobby, and your objective is to get from point A to point B in an airplane, then just buy something used if you want to save money.

You can buy some "not designer label" already flying E-AB aircraft for less than the cost of a kit + engine.

 

[Daleandee]

Out of curiosity, could you build an RV-10 for less than $250K?

An article from Kitplanes (three years ago) gives an estimated completed price between $85,000–$225,000. Could I build it for that? No, unless those lottery numbers I got from the Waffle House waitress are good ...

The Modern RV-10 - KITPLANES

A well-modded RV-10 points to the state of the art in homebuilt four-placers.

www.kitplanes.com