Odd Question: What can be N-numbered?

I was having a conversation with someone about experimental vs ultralight rules (we were talking about Mini Max Ultralights), and he mentioned something I did not consider: what if an amateur-built ultralight is modified out of ultralight status, can it be N-numbered?

It led me to think about some other scenarios that I am curious about:

If someone were to build an ultralight, document it, fly it for 300 hours with a Rotax 337, and then replace that with a 503, could they register it at that point?

If they did not document the build (but still built it)?

If they did not modify it over 254lbs, could it still be registered?

If they purchased it with the 337 and a build log, then added the 503?

If they purchased it without a build log, but it is a model that was never built by a factory?



This all spiraled into one last, odd hypothetical, could a pilot, pursuing an ATP license, build a backpack style powered parachute, have it N-numbered, get a Powered Paraglider Sport pilot license and log that time toward total time for 61.159 flight requirements (as long as they meet the other flight requirements?

For the record, I don't plan to do this, and I expect a regional would hesitate before hiring someone with 1500 hours TT with 500 hours logged in a parachute. I'm just curious if it meets the FAA requirements.

Any of these examples may be certificated as an Experimental Amateur-Built Aircraft, IF it can be shown to be amateur-built. There must be SOME form of documentation acceptable to the inspector. A signed and notarized form 8130-12 must be part of that documentation.

You'll need not just to have built it for "recreation or education" purposes but show some minimum standards. You can't just register any piece of flying junk as E-AB.

If the mods don't invalidate the part 103 restrictions, there's no registration or experimental certificate needed.

Just because it was never "factory produced" doesn't make it legal E-AB. You still have to show that the plane was primarily constructed for educational or recreational purposes. Frankly, with something like an ex-UL, you can probably disassemble it enough to convince the inspector that you did a majority of the tasks.

There's not any longer a path for converting fat (or two seat) ultralights to light sport directly. That ship sailed long ago.

You can register an ultralight, fat or not, even if it has already flown, as E-AB provided you have the build documentation showing that it was indeed amateur built, and provided that it wasn't so prefabricated by a kit manufacturer that it's just a bolt together assembly (< 51%). AC103-7 talks about this.

You can't register a backpack powered paraglider because the rules now say it must have a landing gear, and they don't mean feet.

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Originally Posted by Dana

You can't register a backpack powered paraglider because the rules now say it must have a landing gear, and they don't mean feet.

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"Hey, my landing gear is from Van's..."
Attachment 7810

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Originally Posted by FlyingRon

...but show some minimum standards. You can't just register any piece of flying junk as E-AB...

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Not to argue, but can you point me towards a specific part of 14CFR49 that describes the minimum standards?

My understanding has been that if the paperwork is in order, if you offer compelling evidence that the major portion rule was observed, if the operating limitations are clearly spelled out and the handles are marked, the N-number and EXPERIMENTAL placard per the regs, then the FAA cannot deny you a special airworthiness certificate for the operation of an amateur-built aircraft. They might drag their feet, they might assign you an onerous Phase I test area (like a one mile radius around Ely NV, operations only to be conducted between noon and 12:30pm, etc), but they cannot deny you the certificate. That's as I understand it, but I'd be glad to hear of specific rules or counterexamples that contradict my understanding.

The rationale I've heard for this approach is that the FAA specifically wants to stay out of the business of doing any engineering evaluation or validation of homebuilts, and they'll stay well away from the slippery slope to do that.

Mind you, I'm not proposing that registering a broom or a bicycle as an amateur-built experimental is a good or prudent or rational thing to do. Just that you can do it if you are persistent and somewhat bloody-minded.

--Bob K.

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Originally Posted by BoKu

Not to argue, but can you point me towards a specific part of 14CFR49 that describes the minimum standards?

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Bob,

You are correct. There are no "standards" that apply to experimental aircraft. The criteria is "condition for safe operation". Sometimes the applicant and the inspector have to do some negotiating to come to an agreement as to what "condition for safe operation" includes or implies, but there are no standards that can be applied. There are many kits that included items that are not in line with traditional aviation standards, but that doens't make the aircraft ineligible for an airworthiness certificate. The only overarching requirement is "condition for safe operation". How you achieve that may take many different paths.

They're going to want to be assured of some minimum flight safety and compliance with things like 91.205 (even if it just says STANDARD).

The Operating Limitations for an aircraft with an Experimental Airworthiness Certificate state that it does not need to comply with FAR 91.205 unless it will be operated at night or in IMC. Daylight VFR operations do not require any instrumentation. Joe correctly stated that there are no minimum flight safety standards that can be enforced per FARs.

What about seat belts? (91.107)

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Originally Posted by Sam Buchanan

The Operating Limitations for an aircraft with an Experimental Airworthiness Certificate state that it does not need to comply with FAR 91.205 unless it will be operated at night or in IMC. Daylight VFR operations do not require any instrumentation.

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I go back and forth on this one. Some days, I agree that 91.205 doesn't apply for EAB aircraft operated day VFR only since the OL's only discuss complying for night/IFR, and some days, I don't. While there is an explicit statement saying that one must conform to 91.205 in order to fly night/IFR in the Operating Limitations, there's no explicit exemption for day VFR, and in any case, EAB aircraft are subject to part 91. So it's not obvious to me that 91.205 doesn't apply to day VFR EAB aircraft by default, and they just wanted to be completely explicit about equipping for night/IFR.

Not clear, without a ruling from the legal department. I know that some aircraft have been certificated as EAB without a full 91.205 panel, even for day VFR, but that only means that someone convinced the examiner/DAR, or that the examiner/DAR's view of the rules is unclear as mine.

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Originally Posted by Sam Buchanan

Joe correctly stated that there are no minimum flight safety standards that can be enforced per FARs.

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So I'll disagree with those that believe that there are no minimum standards for EAB aircraft, at least per the documentation. If we take a look at Order 8130.2J, Chapter 15, we can see that it clearly spends most of its time discussing paperwork and the legality of kits. However, section 15-4(c)(5) says:

"(5) Condition for Safe Operation. Inspect the aircraft to verify it is in a condition for safe operation. The sample checklist for a condition inspection in appendix 1 to FAA AC 90-89,
Amateur-Built Aircraft and Ultralight Flight Testing Handbook, may be used for determining if the aircraft is in a condition for safe operation"

To me, this is explicit that the the FAA examiner or the DAR is SUPPOSED to be doing the equivalent of a CI on the plane and should not issue an AC unless they believe that the aircraft "is in a condition for safe operation".

Now, in reality, of course, the chance that the FAA examiner or DAR is qualified to determine such a thing for some arbitrary aircraft is relatively low and everyone is correct that it's unlikely that they'd ever decline to issue the AC except for extremely egregious circumstances - I've done over 130 CI's and Pre-Buy exams in the past 6 years and have seen airplanes that shouldn't have been allowed to be hung from the ceiling of a museum as a representation of what an airplane should look like, much less ever had an AC issued, so I can't even imagine what it would take for an examiner or DAR to decline to issue an AC based on the above paragraph.

But the order, which is titled "Airworthiness Certification of Aircraft" and defines what the examiner/DAR should be doing in order to issue an AC, seems clear that at least a small part of their job is to determine "if the aircraft is in a condition for safe operation", and this does meet the requirement of "minimum flight safety standards", however vague those might be (and they are).

Well stated, Marc. I agree the rules are sufficiently ambiguous enough on the above points that reality is sometimes contrary to what is often thought the FARs require.

I've read various discussions from time to time about the applicability of 91.205 to VFR flight for E-AB aircraft. From what I've gathered while technically no instrumentation is required, getting an FAA inspector or DAR to sign off on the AWC would be problematic.

And for those who might say they have to sign off, you'd be wrong. I personally know one FSDO inspector that insists on there being a whiskey compass installed in the plane even though the FARs clearly state otherwise. No compass no sign off -- simple as that. Not saying it's right, just pointing out that this is a case where theory and reality have the likely potential to clash. YMMV...

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Originally Posted by Auburntsts

I've read various discussions from time to time about the applicability of 91.205 to VFR flight for E-AB aircraft. From what I've gathered while technically no instrumentation is required, getting an FAA inspector or DAR to sign off on the AWC would be problematic.

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It has been pretty solidly established that 91.205 does not apply for day VFR operations of experimental aircraft. The key word in the regulation is "standard". The airworthiness certificate issued to these aircraft is a "special" airworthiness certificate, so they are not "standard" aircraft. (The passenger warning that is required to be installed also specifically states that the aircraft does not conform to the safety standards of "standard" aircraft.) This is covered in DAR training, and is widely understood in the DAR community.

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Originally Posted by Auburntsts

And for those who might say they have to sign off, you'd be wrong. I personally know one FSDO inspector that insists on there being a whiskey compass installed in the plane even though the FARs clearly state otherwise. No compass no sign off -- simple as that. Not saying it's right, just pointing out that this is a case where theory and reality have the likely potential to clash. YMMV...

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And you said the magic words - "FSDO inspector". Most FAA-employee inspectors have not been through the specific training that the DARs are required to undertake, so they actually haven't been exposed to the full discussion of this information. And when the FAA inspectors DO come to the training, they come in with the kinds of preconceived ideas that you describe. I used to be one of the instructors for the DAR training, and I may have actually talked to the inspector you are referring to. Just could NOT knock him off his pedestal on the "whiskey compass" thing. He never did acknowledge that he was wrong, even after multiple instructors discussed the situation with him. I wonder if he's ever come around to the fact that you don't need a "whiskey" compass even in a standard aircraft anymore. The magnetometers that are used in the new glass panels meet the requirement for a north-seeking compass, so no actual compass is required.

But you are right, we are not required to issue a certificate. There are many reasons why we might deny a certificate. But we can't just decide we don't like the thing and refuse to issue. We have to have specific legal basis for the denial, and as a DAR, I would never deny a certificate without the blessing of my supervising office. I wouldn't want to fight that battle alone.

As for this inspector you reference, the applicant could take the issue to the inspector's supervisor, to the FSDO manager, and if necessary all the way to FAA HQ. That would be a winnable battle, if the applicant chose to take a stand. But of course it's a lot easier just to install a compass for the inspection and be done with it.

Since 1999, I have certificated over 900 Amateur-Built and Light Sport Aircraft. I have denied only 2. And I promise there was justification for both of them. One of them corrected the problems and came back to me. I eventually issued the certificate. The other one I denied was subsequently signed off by another DAR. The object of my denial failed in flight within months after the sign-off.
When a DAR denies an airworthiness certificate, it must be done in writing and sent to the applicant, and Oklahoma City, explaining in detail the reason for the denial. This letter of denial is immediately sent to all qualified inspectors in the U.S. If another ASI or DAR decides to issue a certificate, he/she certainly has the right to do so.

I've heard the old chestnut that the only instrument that is required is a compass from a few folks.

It would be interesting to find out what the original source of it is.

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Originally Posted by Sam Buchanan

The Operating Limitations for an aircraft with an Experimental Airworthiness Certificate state that it does not need to comply with FAR 91.205 unless it will be operated at night or in IMC. Daylight VFR operations do not require any instrumentation. Joe correctly stated that there are no minimum flight safety standards that can be enforced per FARs.

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Irrelevant. The operating limitations (and you're only quoting the example ones which may or may not be exactly the ones issued), only apply to the plane once the experimental certificate is issued. You let me know if your inspector/DAR would sign a plane off without a reasonable complement of the 91.205 stuff, or seat belts, etc...

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Originally Posted by Frank Giger

I've heard the old chestnut that the only instrument that is required is a compass from a few folks.

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I'm just as disoriented as you are Frank. I do recall flying a few TC'd gliders that had no compass.

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Originally Posted by FlyingRon

Irrelevant. The operating limitations (and you're only quoting the example ones which may or may not be exactly the ones issued), only apply to the plane once the experimental certificate is issued. You let me know if your inspector/DAR would sign a plane off without a reasonable complement of the 91.205 stuff, or seat belts, etc...

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I have no intentions of being argumentative about this, only stating the situation as I have known it for over 25 years and the certification of three personal experimental aircraft. In each case, and in all the cases I am aware of while assisting many RV aircraft builders, the Operating Limitations have been stated as I referenced in an earlier post.

So this is not irrelevant if we are discussing what the FARs require. If we believe a "reasonable complement of 91.205 stuff" is required......who defines "reasonable"? We then start down the slippery slope of creating regulation where none exist.

My RV-6 that was inspected in 1999 was the first one my DAR had seen that had zero conventional instruments. All flight and engine information was displayed by two small solid-state devices, and there was no conventional magnetic compass in the aircraft. After a short period of "Wow, this is different" comments he proceeded to award the airworthiness certificate. We had a good chuckle as we discussed how to apply colored limit markings to electronic instruments---when I showed him the programmed alarms he was satisfied...and impressed. Remember, this was 1999....and I didn't make any night flights until the RV had a more sophisticated EFIS in the panel.

A friend of mine with an RV-6A certificated during the same period recieved his certificate with a panel that consisted of three iPAQ handheld devices (different DAR).

So there are DARs that are willing to work within the confines of the Experimental Operating Limitations as they are written. Perhaps they are the exception, but I respect their willingness to comply with regulations as they are written and refrain from making up regs that they think are appropriate. When that happens we are dealing with regulation anarchy.

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Originally Posted by Joda

It has been pretty solidly established that 91.205 does not apply for day VFR operations of experimental aircraft. The key word in the regulation is "standard". The airworthiness certificate issued to these aircraft is a "special" airworthiness certificate, so they are not "standard" aircraft.

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Very good. That's the argument I needed to hear, and I agree that the logic makes sense.

I find it a bit strange that the FAA would exempt Experimental aircraft from the day VFR 91.205 requirements, but whether a loophole or intentional, you've convinced me.

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Originally Posted by Joda

But you are right, we are not required to issue a certificate. There are many reasons why we might deny a certificate. But we can't just decide we don't like the thing and refuse to issue. We have to have specific legal basis for the denial, and as a DAR, I would never deny a certificate without the blessing of my supervising office. I wouldn't want to fight that battle alone.

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I certainly understand the desire for support, but isn't "it's not in a condition for safe operation", per the paragraph I quoted above, enough? Otherwise, why put that in there?

Using unconventional/uncertified instances of instruments is what experimental is all about. That's not the same as not having any airspeed, altitude information presented.

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Originally Posted by FlyingRon

Using unconventional/uncertified instances of instruments is what experimental is all about.

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I learned at Sun-N-Fun that our friends to the north (TCCA - Canada) have an "owner maintenance" category for previously certificated airplanes that are more than 30 years old with no manufacturer support. The example was the presenter's Stinson 108. He has replaced all of the instruments with Arduino-based, digital units. Awesome!!!

PS. Yes, the airplane airworthiness in the certified category is no longer valid.

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Originally Posted by FlyingRon

Using unconventional/uncertified instances of instruments is what experimental is all about. That's not the same as not having any airspeed, altitude information presented.

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Meh. They're "nice to have" but hardly required for flight. I flew without an ASI for about a year with no ill effect.