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LSA 'Maximum Empty Weight' clarification

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Sep 6, 2007
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I posted this over at supercub.org, but someone indicated it really should be here. Thanks.

A customer just sent me a note that the topic of S-LSA certification was being discussed on your site. He sent me a few of the posts, and I think I can contribute by clearing up some misinformation on the Maximum Empty Weight issue for S-LSA aircraft. We have been getting a lot of calls here at CubCrafters about this as well, so apparently there is considerable confusion and/or concern around the topic.

First, you can go to FAR Part 21, Subpart H Airworthiness Certificates, Section 21.190: Issue of a special airworthiness certificate for a light-sport category aircraft to see where the requirements to issue an S-LSA airworthiness certificate are detailed. Those places in that FAR where “meeting the consensus standard” are called out are in reference to the agreed upon ASTM Standards on Light Sport Aircraft. I am pretty sure all of this information is publicly available.

In short, the Maximum Empty Weight of a 2-place, 100hp, S-LSA on wheels cannot exceed 890 Lbs in any configuration, including the weight of all optional equipment. The Maximum Gross Weight for that airplane is 1,320 Lbs. If that same airplane is equipped for float operations (i.e. floats are installed), the Maximum Empty Weight is 1,000 Lbs and the Maximum Gross Weight is 1,430 Lbs for that float-equipped airplane. All of this information, including the correct formulas and calculations, can be found in much greater detail in ASTM 2245: Standard Specification for the Design and Performance of a Light Sport Airplane. ASTM 2245 is one of several of the “consensus standards” that a manufacturer must comply with to legally certify S-LSA aircraft.

Interestingly, there is more urgent information on the subject that you may not be aware of coming from the FAA, EAA, and the LSA industry trade group LAMA (the Light Aircraft Manufacturer’s Association). Each seems very concerned about compliance with this particular Maximum Empty Weight limitation for S-LSA. LAMA sent this “Industry Alert” out below - only the second one it has ever issued - to all LSA manufacturers just a few weeks ago on 7.25.07. The “Alert” not only clarifies the certification requirements around weight, but it raises the issue of “non-compliance status and FAA action for both new and existing S-LSA aircraft” if those aircraft ARE NOT in compliance with the Maximum Empty Weight specification or any other certification requirement. Questions are already being raised about how an S-LSA airplane (100hp, 2-place) that weighs more than 890 Lbs empty is “legal” or is going to pass its annual condition inspection, but in our case, every CubCrafters S-LSA produced has come under the Maximum Empty Weight certification limit.


Todd Simmons
President, CubCrafters

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