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Christavia LSA?

Posted: Wed Aug 30, 2017 7:49 pm
by awilson
Does anyone know if you can certify an experimental as a LSA if you place the gross at 1320 even though the gross per the designer is 1500? Obviously I'm talking about an aircraft that has never been certified before. If someone questions the useful load can't I just make it a single seater by taking out the rear seat?

Re: Christavia LSA?

Posted: Wed Aug 30, 2017 8:00 pm
by drseti
If you're talking an Experimental Amateur Built, you can set the max gross weight anywhere you want, as long as the Designated Airworthiness Representative will agree to sign it off - so check with your DAR before you start the build. Remember that to be an LSA (and Sport Pilot eligible), it must comply with all LSA limitations, not just weight. Be sure to review the FAR 1.1 definition of LSA.

Re: Christavia LSA?

Posted: Wed Aug 30, 2017 10:02 pm
by 3Dreaming
Aircraft are not certified as LSA, they are LSA because they meet the definition. You would register the airplane as experimental amueture built. As the builder you should be able to set the maximum gross weight to what ever you want, regardless of what the designer says the weight is. The numbers need to be resonable in that you can get in the airplane with enough fuel to make a flight.

Re: Christavia LSA?

Posted: Thu Aug 31, 2017 6:13 am
by drseti
Tom is right. There are LSAs out there with all kinds of airworthiness certificates: Standard, Special operating SLSA, Special operating ELSA, Special operating E-AB, Special operating E-Exhibition, Special operating E-Limited, etc. In your case, awilson, Special E-AB seems most appropriate. But, you need to discuss this with your DAR or local FSDO airworthiness inspector before you commit to the build.

Re: Christavia LSA?

Posted: Fri Sep 01, 2017 7:57 am
by Awilson62
Thanks guys this gets me started. Pretty logical.

Re: Christavia LSA?

Posted: Fri Sep 01, 2017 8:15 am
by rsteele
A couple of other things about an EAB as an LSA. Most kit manufacturers will tell you if the kit is LSA compliant. If they don't specifically say something about it, you can be pretty sure it's not. Also some kits are LSA compliant, but can be flown safely, that is registered, at a somewhat higher gross weight than the 1320Lbs allowed under the LSA rule. I know the Zenith 750 series is like this, for instance. However, if you ever want to fly your plane as a sport pilot don't register it at a higher gross weight. If you do, it can never meet the LSA rule as the rule doesn't allow non-compliant planes to become compliant (which idiocy IMHO). There are a lot of Ercoups out there that were caught out by this.

Ron

Re: Christavia LSA?

Posted: Fri Sep 01, 2017 8:53 am
by Warmi
So theoretically , I could build a kit plane that is , say 500 lbs max gross over lsa limits and can cruise at , maybe 150 knots - as long as I register it with limits defined by lsa standards, I am good to go ?

Re: Christavia LSA?

Posted: Fri Sep 01, 2017 2:33 pm
by TimTaylor
Warmi wrote:So theoretically , I could build a kit plane that is , say 500 lbs max gross over lsa limits and can cruise at , maybe 150 knots - as long as I register it with limits defined by lsa standards, I am good to go ?
No, it has to meet all the LSA standards including max gross weight, flaps up and down stall speeds, etc. The empty weight and useful load would have to be such that it can be operated with a max gross weight of 1320 pounds.

Re: Christavia LSA?

Posted: Fri Sep 01, 2017 3:00 pm
by rsteele
TimTaylor wrote:
Warmi wrote:So theoretically , I could build a kit plane that is , say 500 lbs max gross over lsa limits and can cruise at , maybe 150 knots - as long as I register it with limits defined by lsa standards, I am good to go ?
No, it has to meet all the LSA standards including max gross weight, flaps up and down stall speeds, etc. The empty weight and useful load would have to be such that it can be operated with a max gross weight of 1320 pounds.
To elaborate a bit on Tim's response. There is a big difference in building a kit designed to be an LSA, but is capable of higher gross weight, and changing a non-LSA kit to an LSA kit. It the first case, all the engineering "fits" and it's up to the builder to decide on the gross weight (LSA or non-LSA). In the second, you are basically redesigning an aircraft to get all the LSA numbers correct. I wouldn't attempt this unless I was an aeronautical engineer.

Re: Christavia LSA?

Posted: Fri Sep 01, 2017 3:34 pm
by 3Dreaming
In my opinion you guys are making this more difficult than it really is. As the builder you establish the gross weight at 1320 pounds. Obviously you can't have an empty weight that is unrealistic, but you also don't have to be able to carry 2 170 pound people and full fuel either. During flight testing you will have to establish power limits that keep the speed within LSA limits. It is simply paperwork and a little common sense.

Here is an example of what can be done. American Champion offers the Champ. The model is a 7EC. The type certificate shows the gross weight as 1450 pounds, with a notation that says see note 16 for further weight information. Note 16 says that airplanes built after 2006 have a gross weight of 1320 pounds. It was just a paperwork change to make the airplane legal for sport pilots. The airplane has a useful load of 395 pounds in standard configuration. With 2 170 pound people on board you can only carry about 1/2 fuel.

This would not be much different than what the OP was asking about doing with the Christavia.