Experimental LSA

I have gotten conflicting info from two different DAR's about the weight rules for LSA's. The issue was concerning Experimental amateur built, no kit-just an old -fashioned homebuilt. If this aircraft has two seats and one 18 gal fuel tank what can it weight empty and still qualify to be flown by a light sport pilot or private pilot using his drivers license with no class 3 medical. This is a little off the RV-12 but is important for general LSA info.

Thanks
Jim Miller

1320 lbs GROSS is the limit, from my understanding. There has been nothing said about how much of that should be payload.

Just like what Fred said, it doesn't matter what airplane it is (certified, experimental, etc.)...as long as it fits within the LSA ruling it can be LSA, which means a max gross of 1320 (empty weight doesn't matter), only two seats, fixed gear, etc.

www.sportpilot.org has all this for you. Look in the Aircraft section for all the limits.

empty or gross...

The first error is that LSA/sport pilot regulations have nothing to do with empty weight, Only ultralights (part 103) have an empty weight requirement (254 lbs.). It is 1320 lbs gross weight that you care about. If an airplane has placarded gross weight of 1320 lbs or less, no more than two seats, a top speed at continuous power at SEA LEVEL of 120 knots or less, fixed pitch prop and reciprocating engine (no turbines or jets) that's basically it. Their is no fuel limit either, You can fly it. Doesn't matter if it is a j-3 cub, quicksilver sport, Kitfox or a Hatz Bi-plane nor does it matter if it is amateur built, restricted, exhibition or certified. If you look up the rules for LSA's and you will find the specs listed, they include stall speed requirement as well but can't remember what it is. (hint... the specs for the rv-12 are almost exactly number for number the specs for LSA). Most DAR's and FAA folks do not understand the LSA or ultralight rules and a LOT of confusion is out their.

Here is the rest of the story. One DAR says that you can't just load an airplane to comply with the 1320 wt limit. The other says that experimental amateur built is different from SLSA and that in fact you can. For example for a company such as vans has to built a plane that can be fully loaded Two seats full @180 times 2. Plus full fuel 3. plus full baggage as stated in certification paperwork and fall at or below 1320. Now on the other hand can a homebuilt that has 2 seats and 18 gal fuel be flown by skinny pilot and his skinny wife with full or partial fuel at a gross wt of 1320? When it is loaded like Vans RV-12 it would be way over weight? If so then there is a difference between a SLSA and experimental amateur built. This is the part I don't understand.
Jim PS I was told the key here is that the LSA rules specify a rigid definition for the 1320 limit as "maxium takeoff weight" and that means something more specific that gross weight. Does anyone with the full document have the definition for "Maxium takeoff weight" (1320)

ELSA is different than SLSA. If you build a plane, YOU can certify it to fly at whatever weight you want. Some RV builders ocassionally set gross weight at 50 lbs higher than Van's recommends. Is it prudent? Maybe. Maybe not. YOU'RE the aircraft manufacturer. With SLSA, gross wt is set by that manufactuer. The DATA Plate will specify whether it qualifies. If the Data Plate shows gross weight at 1321 lbs (or more) - you're out of luck (and it's not an SLSA).

Regarding Max Take-off Weight: I assume that so long as the wheels remain on the ground, and you have the capacity, you could put in some additional fuel exceeding 1320 lbs so long as it was burned off during taxi and run-up.

Actually, there is a formula for maximum empty weight as stated by the LSA advisory board, but it applies to ready-to-fly (SLSA) versions. For two-seat SLSAs, it's 380 + (0.5 x max horsepower). For single seaters, it's 190 + (0.5 x max horsepower).

Doesn't apply to Experimental/Amateur-Built aircraft that otherwise meet the LSA requirements for weight, top speed, stall speed, number of seats, etc.

--Marc

Fred
I hope you are right. It would certainly give a great advantage to homebuilt/LSA. However on a recent Q&A website (I can't recall the sponser) there was a long discussion regarding the FAA definition of "maxium takeoff weight" as defined for the LSA class. They made a big deal about how it is specific and cannot be interchanged with other terms such as gross weight. This definition forms the basis from which all SLA manufactures operate. It must be spelled out somewhere in the 350 pages of the LSA rules. If you just look at the basic rules they do call the 1320 limit "maxium takeoff weight" and must define this term somewhere.

Jim Mark: So a person could placard his exp limiting passenger to a certain weight for an exp LSA?
That is what I understood also until my local DAR said otherwise and I saw the above mentioned
website. All classes of LSA's specify the 1320 as "Maxium takeoff weight" so I will somehow find
its definition and present to my DAR so both of us will be on the same page.

Thanks Jim Miller

FredMagare said:

Regarding Max Take-off Weight: I assume that so long as the wheels remain on the ground, and you have the capacity, you could put in some additional fuel exceeding 1320 lbs so long as it was burned off during taxi and run-up.

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Exactly. Transport aircraft tend to have a "max taxi weight" and a "max takeoff weight." In an airliner it can be a substantial number, in an RV it is pretty minor, on the order of 30 pounds per hour of taxi time. So, be sure to consider the 5 pounds you will use for a 10 minute taxi.

John Clark
RV8 N18U "Sunshine"
KSBA

I suppose if "gross weight" and "max take-off weight" are not interchangeable, one could conceivably have an aircraft that can carry a higher gross weight but is limited to 1320 lbs. Now that I think about it, this makes sense! I know that the Sky Arrow's gross weight is something like 1450 lbs, but their SLSA version is placarded at 1320 lbs even though it is EXACTLY the same aircraft - engine and all! (There's the difference between "gross weight" and "max take-off weight".)

I guess what I need to do is find the reference to show my DAR. Decisions on electrical system and other mods hinge on us comming to an understanding on this question. I have a down loaded copy of the 19 page condensed LSA rules but can't find the references on experimental home built/LSA compliant. Where can I find where it spells out how the rules differ for an experimental amateur built versus a S-LSA or a kit built E-LSA. Until I convince him otherwise he is convinced that regardless of how licensed a two place 1. Exp amateur built 2. S-LSA 3. E-LSA has to be able to carry two 180lb people, full rated baggage and full fuel and not weight more than 1320. If this is not so how can i prove it with regs in black and white.

Jim:

I had to go back to your original question before it dawned on me that you're talking about a standard Experimental/Amateur-Built aircraft. The DAR won't find guidance on fitting it to SLSA standards because there aren't any. You would register this airplane as you would any other Experimental/Amateur-Built. Period. End of discussion.

If it happens to meet all the criteria for a Sport Pilot--top speed at sea level on max-continuous power of 120 knots or less, 45 knot clean stall speed, maximum takeoff weight of 1320 or less, max two seats (etc, etc)--then it can be flown by a Sport Pilot.

No need to make this any more complicated than that.

--Marc

The reason for the max. weight rule...

is to prevent certification of an LSA with an unrealistic useful load.

If someone was trying to certify a 950 lb. airplane with a Rotax 912S engine as an LSA compliant airplane, it would not be allowed (even if it meets all of the other performance requirements).
Since the max. gross is 1320 lbs., if the seats each had passengers that weighed only 150 lbs, it would still be limited to less that 12 gal of fuel.
If the weight in the seats totaled at least 350 pounds (Two 175 pounders, probably still low for what might be typical) you would now be down to less than 4 gal of fuel.
The FAA knows that people would over gross (above 1320 lbs) an airplane such as this, so they have minimum useful load weights based on a reasonable fuel payload depending on the size engine installed (related to how thirsty the engine is).

KPmarc posted a formula which is correct, except it is for calculating the minimum useful load, not maximum empty weight as he stated.

It uses the new FAA standard passenger weight of 190 lbs per passenger and .5 lbs of fuel per HP, to have at least a minimal range.
When calculating the minimum useful load, any LSA using the Rotax 912 ULS (100 HP) would have to have a useful load of at least 430 lbs or a max empty weight of 890 lbs. As you can see the example I used at the beginning of the post would not qualify.

As for certifying a new experimental as amateur built and then flying it as an LSA pilot, it is true you can do that if it meets the requirements.

What I have not yet been able to find out yet, is how the FAA determines if it meets them. The EAA web site has a list of airplanes that can be flown under LSA rules. It is not clear who made up that list.

The other thing that is not yet clear to me, is if I apply for certification of a new experimental amateur built airplane listing a gross weight of 1320 lbs, but it has an empty weight of 950 with a Cont O-200 installed, is the FAA going to issue an airworthiness cert. for it. It does not meet the minimum useful load requirements so it is highly likely that it would be flown at a gross weight of above 1320 lbs.

Mel, has the FAA issued any guidelines to DAR's?

If you are certifying the aircraft as amateur-built, it doesn't matter. It is up to you to determine, and "show" if necessary, that it complies for operation by a Sport Pilot.
The loading schedule you guys are talking about is only for S-LSAs. It doesn't apply to E-LSAs or other aircraft to be flown by a Sport Pilot.
This is the interpretation we have been given in the DAR Seminars.
Also remember that the aircraft must have been continuously certificated at a gross weight of 1320 lbs. or less. You can't "back" into the regs.

Mel said:

The loading schedule you guys are talking about is only for S-LSAs. It doesn't apply to E-LSAs or other aircraft to be flown by a Sport Pilot.

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I know that it is for S-LSA only (I should have said that). I was just wondering if the FAA would be applying it as a guideline for anyone operating an EA as a sport pilot.

So, you come out to certify my new original design, 100 HP two seater with a max gross weight of 1320 lbs with two 15 gal fuel tanks, and the weight and balance paperwork shows that it has an empty weight of 960 lbs, you will give me an airworthiness certificate?

It is obvious that I intend to fly it under LSA rules because of the max. gross weight, but the useful load as very near useless.
This wont raise any red flags with the FAA?

Just wondering?

Sure, I'm certifying it as an amateur-built. My certification has nothing to do with your operation of the aircraft.
A similar example is navigation lights. I don't certify it to fly at night. That's an operational issue. The operating limitations say that you can operate at night if you meet 91.205. Now the monkey is on your back. If you have the proper lights, you can fly at night.

I know that you can't back into the sport pilot limits, but can you go the other way? In other words, say I build the lightest RV-9 possible, and set the gross weight at 1320. Assuming I meet the stall speed and max speed, it looks like I could fly this as a Sport Pilot.

If I later decide to sell the plane to someone who does have a medical, and doesn't want the LSA limitations, can I increase the gross weight at that point?

Thanks,
Rusty

Edited to correct my silly mistake

Yes, This is possible.

If the aircraft was originally certified as amateur-built, you can increase the gross weight by placing the aircraft back into Phase I and completing the necessary flight testing.
If the person you are selling to doesn't have a medical, why would you want to increase the gross weight?

Mel,

I might have missed it but, can you give us the specific definitions of max gross weight and max gross takeoff weight as it relates to Exp. Amature Built aircraft that are being built to be LSA compliant?

I once enquired about a kit aircrafts ability to comply with the LSA specs and though it's advertised max gross was 1400lbs I was told it's not a problem because as the builder you can set the weight as you wish, ie 1320lbs. That sounds like fudging the numbers even though you knew when you built it to plans it's max gross was 1400lbs. Is their something dishonest about that or is it just me and wouldn't a DAR pick up on that?


Mike

Mel said:

If the aircraft was originally certified as amateur-built, you can increase the gross weight by placing the aircraft back into Phase I and completing the necessary flight testing.
If the person you are selling to doesn't have a medical, why would you want to increase the gross weight?

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Thanks Mel. Sorry about the silly mistake. I meant to say if I sold the plane to someone who "does" have a medical. I edited the previous post to correct that.

Cheers,
Rusty (what will he build next...)

Mike Armstrong said:

I once enquired about a kit aircrafts ability to comply with the LSA specs and though it's advertised max gross was 1400lbs I was told it's not a problem because as the builder you can set the weight as you wish, ie 1320lbs. That sounds like fudging the numbers even though you knew when you built it to plans it's max gross was 1400lbs. Is their something dishonest about that or is it just me and wouldn't a DAR pick up on that?


Mike

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I understand your point. And it may indeed raise an eyebrow, but it is perfectly legal.
What if say you don't have total confidence in your building abilities and want to add a "guard band" to your aircraft. I know this is a stretch, but it shows that there may be other reasons for applying a more conservative GW.
The TEXAS SPORT kit can be built with a gross weight of either 1320# or 1600# depending on whether or not you want to operate it with a sport pilot or private pilot certificate

Mel said:

I understand your point. And it may indeed raise an eyebrow, but it is perfectly legal.
What if say you don't have total confidence in your building abilities and want to add a "guard band" to your aircraft. I know this is a stretch, but it shows that there may be other reasons for applying a more conservative GW.
The TEXAS SPORT kit can be built with a gross weight of either 1320# or 1600# depending on whether or not you want to operate it with a sport pilot or private pilot certificate

Click to expand...

Thanks Mel, but it still sounds fishy to me.

Thanks for the many replies to my question. I think I now understand the rule and am in process of discussing with the DAR I am working with. As I understand it now experimental amateur built is totally unaffected by the LSA rules. The gross weight I can certifiy at will be affected only by demonstrating common sense numbers acceptable to the DAR and in line with design specs which has always been the case.

Thanks
Jim Miller