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Thread: Carbon Cub question

  1. #1

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    Carbon Cub question

    I see the Carbon Cub EX approved to 1800+ pounds but can be amateur built and certified at 1320# so it can be legally flown by an LSA qualifying pilot. The Cubcrafters site does not specify the kit is eligible as E-LSA but only amateur built. Interesting. The questions are

    1) when during the build process is the gross weight declared?

    2) with the future potential increase of gross weight for no-medical pilots, could a 1320# amateur built Carbon Cub be re-declared to have a higher gross? I understand that a higher gross airplane can't be reclassified for LSA but I've never seen anything about increasing the gross.

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    I have been going thru this question with a local DAR who is totally confused on this question. I am building a exp cub/supercub and plan to limit
    my gross weight to 1320. As I understand it you declare 1320 at the time of sign-off. The only requirement is to have reasonable numbers for
    "payload" with payload being 1320 minus empty weight plus full fuel. This is where the DAR has a problem in stating that I have to be able to
    carry two 190 lb people (Pilot and passenger) plus baggage and still meet the 1320 max gross weight. This is totally wrong as the EAA has
    confirmed it is wrong. As far as going to a later higher gross weight the original builder should have no problem especially when the same aircraft
    type can be shown to function fine at 1800. It may be harder for a future purchaser and not the original builder to increase gross. I am curious what
    does the factory list the 1320# version's empty weight without fuel as being?

  3. #3
    Clay Hammond's Avatar
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    Just to clarify, the kit is E-AB certified no matter what. The builder may limit the gross weight to 1320 (1430 on floats) if they wish to operate LSA with it. E-LSA certification is a mechanism in which a factory built, S-LSA certified aircraft may move into Experimental category and more easily be modified and/or maintained.

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    Agreed, mostly. It seems there are options to build E-LSA but it wouldn't be my choice. I was doing some research and came across this article by Joe Norris. That's what got me thinking about a builder modification that would raise the gross weight after the plane is commissioned. I know where to get the info on Monday but wondered if anyone here knew the answer.

    http://www.eaa.org/experimenter/arti...10_darside.asp

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    Gordon Misch's Avatar
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    A couple of years ago I attended a presentation by Randy Lervold, Cub Crafters' general manager, on the Carbon Cub EAB. We were told that if the builder sets the gross weight to meet LSA specs, the gross weight could later be increased to 1865 lb by either the builder or a subsequent owner. However, the reverse (gross weight reduction to meet the LSA spec) would not be allowable.
    Gordon

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    spinner2's Avatar
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    Carbon Cub question

    SB, I see you're getting answers that are a little different that what we PM'd. I'm sure you'll get to the bottom of this and I look forward to knowing for sure if the gross can be changed at a later date.

    My CC is EAB with 1865 gross.


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    I'll get to the bottom of it. I have lots of questions.

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    The local FSDO told me that same thing as Gordon stated above. Gross weight can be increased above 1320 but one cannot go back (Gross weight reduction)

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    "The only requirement is to have reasonable numbers for "payload" with payload being 1320 minus empty weight plus full fuel. This is where the DAR has a problem in stating that I have to be able to carry two 190 lb people (Pilot and passenger) plus baggage and still meet the 1320 max gross weight."

    Don't think that's right. If your building experimental/amateur built you get to set the empty weight even if you can only carry a pound of fuel and no people at all. I don't think there is any "useful load" requirement even though it seems silly. I think where this started is that a factory like Cubcrafters has to meet a useful load standard for their LSA aircraft and if I remember their LSA can't go over 850 or something like that. You can fly "sport pilot" rules with a 1320 gross weight homebuilt and that's the reason you would limit the weight of your homebuilt to 1320 but it still isn't an LSA. Randy is this correct?

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    Quote Originally Posted by qsmx440 View Post
    "The only requirement is to have reasonable numbers for "payload" with payload being 1320 minus empty weight plus full fuel. This is where the DAR has a problem in stating that I have to be able to carry two 190 lb people (Pilot and passenger) plus baggage and still meet the 1320 max gross weight."

    Don't think that's right. If your building experimental/amateur built you get to set the empty weight even if you can only carry a pound of fuel and no people at all. I don't think there is any "useful load" requirement even though it seems silly. I think where this started is that a factory like Cubcrafters has to meet a useful load standard for their LSA aircraft and if I remember their LSA can't go over 850 or something like that. You can fly "sport pilot" rules with a 1320 gross weight homebuilt and that's the reason you would limit the weight of your homebuilt to 1320 but it still isn't an LSA. Randy is this correct?
    Tell him to be quiet about the 2-190lbs people because you don't date fat chicks.

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    Cubpylut's Avatar
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    I'm not sure about subsequent owners, but if you are the builder of record for a EAB, you can reset the gross downward to the LSA qualifying standard of 1320 as you are the manufacturer of the aircraft. Been done and approved by our FSDO for a friend of mine and we'll potentially do the same for our Wag-Aero Cuby if the need arises in the future.

    James Smith

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    skywagon8a's Avatar
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    Quote Originally Posted by Jim Miller View Post
    This is where the DAR has a problem in stating that I have to be able to
    carry two 190 lb people (Pilot and passenger) plus baggage and still meet the 1320 max gross weight.
    190 lbs is an error. The official FAA weight is 170 lbs and is the number the DAR should be using when looking at your paper work. If you personally weight more than the FAA 170 lbs then it is your responsibility to use the correct numbers for your particular flight but 170 lbs should be used to determine if the plane meets the 1320 lb gross limitation. If you can't meet the 1320 limit with 2 people, just get it approved as a single seat.
    N1PA

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    Doesn't LSA require an empty weight of 900# maximum? The factory built Carbon Cub SS lists empty weight at 892# with standard equipment. They offer a one seat option that removes the rear seat and controls and allows an empty weight of 1092#. I assume that's to allow the owner some flexibility for adding optional accessories and equipment.

    Is the empty weight limit waived for E-AB airplanes that certify to 1320# gross for LS pilot operations?

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    The 190 rule comes from S-LSA rules, the factory built ones. The useful load of an S-LSA must be 190 times 2 plus one half engine horsepower. So for a 100 HP plane, that number is 190+190+50=430. Subtract that from 1320 to get the empty weight.(890 max). That rule is for factory built airplanes only and should have nothing to do with E-LSA or E-AB.

    Some DAR's don't get it.

    Rich

    Edit: unless the S-LSA is a single seat design, then it's 190 times one plus half the engine horsepower. In addition, The Carbon Cub takes advantage of the horsepower piece of the formula by de-rating the engine for "normal" operations to maintain the empty weight. When the airplane can't meet it anyway, they will certify it E-LSA for the buyer.
    Last edited by Richgj3; 11-24-2012 at 07:01 AM.
    Comm/Inst/CFIA/CFII...Now a happy Sport Pilot

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    Quote Originally Posted by skywagon8a View Post
    190 lbs is an error. The official FAA weight is 170 lbs and is the number the DAR should be using when looking at your paper work. If you personally weight more than the FAA 170 lbs then it is your responsibility to use the correct numbers for your particular flight but 170 lbs should be used to determine if the plane meets the 1320 lb gross limitation. If you can't meet the 1320 limit with 2 people, just get it approved as a single seat.

    Skywagon
    You are right about the 170lb standard but according to the technical advisor at EAA this is not spelled out in the experimental rules. Would it not be
    possible to limit total carrying capacity of pilot, passenger, baggage to something around 325, placard the plane to clearly show this. In my case with
    full fuel of 18gal my fully fueled aircraft weight could be 995 lbs which includes fuel of 108lbs and empty aircraft of 887. Add in the pilot/passenger &
    baggage of 325 to equal the 1320. I look at this as a worse case in my yet to be completed project. Would this meet the "reasonable" criteria and
    would a DAR or FAA sign off on it?

  16. #16
    mvivion's Avatar
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    Quote Originally Posted by Cubpylut View Post
    I'm not sure about subsequent owners, but if you are the builder of record for a EAB, you can reset the gross downward to the LSA qualifying standard of 1320 as you are the manufacturer of the aircraft. Been done and approved by our FSDO for a friend of mine and we'll potentially do the same for our Wag-Aero Cuby if the need arises in the future.

    James Smith
    Nope, take a look at FAR 1.1, where the definition of LSA resides:

    Light-sport aircraft means an aircraft, other than a helicopter or powered-lift that, since its original certification, has continued to meet the following
    1) A maximum takeoff weight of not more thanó
    (i) 1,320 pounds (600 kilograms) for aircraft not intended for operation on water; or
    (ii) 1,430 pounds (650 kilograms) for an aircraft intended for operation on water.

    (2) A maximum airspeed in level flight with maximum continuous power (VH ) of not more than 120 knots CAS under standard atmospheric conditions at sea level.
    (3) A maximum never-exceed speed (VNE ) of not more than 120 knots CAS for a glider.
    (4) A maximum stalling speed or minimum steady flight speed without the use of lift-enhancing devices (VS1 ) of not more than 45 knots CAS at the aircraft's maximum certificated takeoff weight and most critical center of gravity.
    (5) A maximum seating capacity of no more than two persons, including the pilot.
    (6) A single, reciprocating engine, if powered.
    (7) A fixed or ground-adjustable propeller if a powered aircraft other than a powered glider.
    ( A fixed or feathering propeller system if a powered glider.
    (9) A fixed-pitch, semi-rigid, teetering, two-blade rotor system, if a gyroplane.
    (10) A nonpressurized cabin, if equipped with a cabin.
    (11) Fixed landing gear, except for an aircraft intended for operation on water or a glider.
    (12) Fixed or retractable landing gear, or a hull, for an aircraft intended for operation on water.
    (13) Fixed or retractable landing gear for a glider.

    The statement "that, since its original certification, has continued to meet the following" is actually pretty clear in its interpretation. If an aircraft has EVER been licensed with a gross weight in excess of 1320 (1430 for seaplanes), then it can NEVER be operated by a sport pilot as an LSA. I poked around the EAA site and couldn't readily find their interpretation of this, but it is pretty clear in the FAR.

    I've discussed this with a DAR regarding a Champ that had it's GW increased above 1320 with an engine change, and asked if one could simply field approve a reduction in GW. Nope, although the FAA has field approved a deviation from the engine change STC so that the original GW was retained, but the engine hp increased. But, once you've increased the GW beyond 1320, it'll never be a legal LSA.

    MTV

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    skywagon8a's Avatar
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    Quote Originally Posted by Jim Miller View Post
    Skywagon
    You are right about the 170lb standard but according to the technical advisor at EAA this is not spelled out in the experimental rules. Would it not be
    possible to limit total carrying capacity of pilot, passenger, baggage to something around 325, placard the plane to clearly show this. In my case with
    full fuel of 18gal my fully fueled aircraft weight could be 995 lbs which includes fuel of 108lbs and empty aircraft of 887. Add in the pilot/passenger &
    baggage of 325 to equal the 1320. I look at this as a worse case in my yet to be completed project. Would this meet the "reasonable" criteria and
    would a DAR or FAA sign off on it?
    Jim, I agree with your scenario. I used the same approach on my recently completed Cub. My empty weight was too high to be able to use the 1320 lbs or the 1430 lbs on floats. I did declare it to be single seat in order to not raise questions about the useful load with full fuel. I used 1999 lbs for max gross. This was to keep it in a lower state registration tax bracket. Also for starters I chose not to spend the big bucks for the 406 ELT, which is not required for single seat. I can add the second seat belt and ELT later as a minor change.
    N1PA

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    This thread seems to point out how arbitrary and useless the 1320# LSA rule is.
    A man has got to know his limitations.
    Dirty Harry

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    Cubpylut's Avatar
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    Mike,

    Apparently our FSDO has a different interpretation since my friend did it and it was approved on his Kitfox Series 6 - reduced gross from 1550 to 1320. He flies frequently so isn't hiding from the FAA which is good since our FSDO rep bases at our airport. Of course he also continues to grant field approvals for so maybe he's just a rebel within the FAA.

    James

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    Quote Originally Posted by TulsaDave View Post
    This thread seems to point out how arbitrary and useless the 1320# LSA rule is.
    I'm going to take a stab at this but I'm definently not the last word. This is all stuff just reading on the group over the years.

    I think the problem is that many people are not aware that there isn't just one rule around this 1320# issue. First are the basic five separate elements: factory built/kit LSA rules, Experimental aircraft amateur built rules, certified aircraft rules, private pilot rules, and finally sport pilot rules. These are all separate issues and interact with each other differently.

    A factory built or kit LSA has to conform to different rules (including the formula quoted by richgj3 in post 14 above) than an amateur built aircraft. A factory LSA can be flown by either a sport pilot or a private pilot and I believe it's LSA certification limits all pilots to operate it under sport pilot rules. Even with a medical it cannot be flown at night by anyone (am I right about this?).

    A certified aircraft that has always had a 1320# or less gross weight limit (example J3 cub) can also be flown by the same pilots as above. A sport pilot and a private pilot without a current medical but holding a valid drivers license can fly the aircraft under sport pilot rules. A private pilot with a current medical can, if the plane and pilot are rated, fly at night and any other way the aircraft is legal to fly including commercial or IFR. It is not an LSA aircraft, just an under 1320 gross airplane. It still requires all repair and annual done by a certified mechanic.

    A homebuilt is different than all of the above in that it can be owner maintained by the original builder. I think the only weight is the gross weight set by the builder. As a practical matter you need to have the empty weight set at something lower than gross but the builder is writing the manual. IF the gross was set at or below 1320 for it's original certification then sport pilot and private pilots with no medical can fly it under sport pilot rules. A private pilot with a current medical can fly the aircraft to the limit of the aircraft and pilots ratings (for instance at night).

    I wonder if some of the confusion comes from assuming our system operates like Canada where you can remove a certified aircraft form the certified category so you can owner maintain it?

  21. #21

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    There certainly is still too much confusion about the LSA/Sport Pilot rule. A good part of it comes from FAA as described above where one FSDO will approve things another will not. We all know this is nothing new, but it is fuel for humor or frustration depending upon your involvement.

    One clarification on the excellent post above. Legend Cubs and I think Cub Crafters Sport Cubs are approved for day and night VFR if properly equipped. Mine is and says so on the operating limitations. I cannot fly it at night because I am acting as a Sport Pilot. My buddy Jim can as he keeps his medical.

    I got ramp checked a while back and was asked how I could be flying my "Cub" without a medical. I explained I was operating as a sport pilot. He asked, " but what is that?" pointing to my Legend. I told him it was a Special Light Sport Aircraft. He asked "what did you do, have it modified?". I said you know you can't do that, right? He agreed after a while. He asked what it said on the airworthiness certificate. I told him it said Special Light Sport Aircraft. I asked if he'd like to see it. He said yes, "maybe I'll learn something". I think he did. After looking at the plane for a while he said "this looks like a real airplane." I told him I thought that was the idea. BTW, all this time the lower door was open and the words "Light Sport" were displayed as required.

    Rich
    Comm/Inst/CFIA/CFII...Now a happy Sport Pilot

  22. #22

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    Quote Originally Posted by Jim Miller View Post
    Skywagon
    You are right about the 170lb standard but according to the technical advisor at EAA this is not spelled out in the experimental rules. Would it not be
    possible to limit total carrying capacity of pilot, passenger, baggage to something around 325, placard the plane to clearly show this. In my case with
    full fuel of 18gal my fully fueled aircraft weight could be 995 lbs which includes fuel of 108lbs and empty aircraft of 887. Add in the pilot/passenger &
    baggage of 325 to equal the 1320. I look at this as a worse case in my yet to be completed project. Would this meet the "reasonable" criteria and
    would a DAR or FAA sign off on it?

    Could some of our DAR's please look at my example and comment on their acessment of what they consider as "reasonable" for a two place
    amateur built experimental empty and gross weight.

    Jim Miller

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