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Maintaining your LSA: few lurking land mines: procedures exist to repair 60-year-old Aeroncas and brand-new Sport Cruisers alike. But owners may have a bigger role--and--headache than they expected.

Back when this whole LSA thing was being conceived, part of the appeal was simplicity: Two seats, fixed-pitch prop, a couple instruments ... what could go wrong?

Actually, a lot can go wrong, break or just plumb wear out. So-called legacy LSAs can have over half a century on their airframes. Corrosion and fatigue mean just about anything can snap. For a Piper J-3, that's no problem. You could literally build a J-3 from scratch with available replacement parts. For an Aeronca C-3, your options are limited.

Flying a new light sport (S-LSA) doesn't guarantee parts and support will be simple. Your experience will almost entirely depend on how the company built the aircraft, how well they prepared for maintenance and how long they stay in business.

Old or new, the first step in protecting yourself is understanding why LSA maintenance is different and knowing what questions to ask before you buy.


Supportability for legacy LSAs is primarily a numbers game. If enough airframes of a particular are model flying, then it's probably worth someone's trouble to supply parts. That's what makes models like the Piper J-3 (Cub) and PA-11 (Cub Special), or the Aeronca 7AC (Champ) and 11AC (Chief) good picks.

Even when there are sufficient numbers, however, out-of-business companies can mean other roadblocks. Taylorcraft owners are dealing with this now in that the current owners of the type certificate won't release the engineering data for the aircraft (they'd like someone to buy the type certificate instead). This makes fabricating replacement parts challenging because of an FAA policy called "identicality." In order to supply a replacement part for a certified aircraft, the manufacturer must prove that the part is identical to the original. If identicality can be shown, then the part can be used as if it were the original part.

"Identical is a pretty tough word," said Bill Reed, president of Wag-Aero Group, "especially if you don't have the original design data." Reed told us they rarely try to fabricate parts outside of this identicality rule as that would require a supplemental type certificate (STC), which is an even tougher process. STCs only make economic sense with large sales volumes, such as the popular STC for putting fuel tanks in the wings of Aeroncas that originally only had a fuselage tank.


Whether it's a legal part under identicality or STC, legacy LSAs are certified aircraft and any patts must be approved in some way. That's not to say you can't use screws from Lowes to hold down a piece of trim. It just means any repairs should be logged as required and significant parts must have the right paper trail (and commensurate price tag) to be airworthy.

The takeaway message for you as a prospective buyer is that close examination of both the airframe and the available parts chain is in order. Your best friends will be the experts in a type club for that aircraft of interest because you need specifics for that particular airframe. For example, if you're looking at a Cub with a Continental engine installed, you want the Airworthiness Certificate to say something like "13C-65." The C is for Continental. If it says "13L-65" (Lycoming) or "13F-65" (Franklin), then there had better be an appropriate FAA Form 337 in the logbooks for the engine switch. Looking at a T-craft that needs its old lift struts replaced? It'll set you back $3000, but they're available from three sources. Need cowling metal for that same aircraft? Plan to supply it yourself (That's right, yourself. See sidebar, page 17).

The plus with these aircraft is that supportability is a known entity.


Buying a new S-LSA is more of a crap shoot in that we know some of the companies selling today won't be around 10, or even five, years from now. There are actually two issues with company support: maintenance (which include parts availability) and modifications.

With the S-LSAs, regulations are looser on parts, Jabiru engines use NGK motorcycle spark plugs and the oil filter from a Toyota Camry. Many LSAs use automotive light bulbs you can pick up at NAPA. Where LSAs use more specialized parts, we like to see LSAs that use aircraft parts common in the U.S. and available from places like Aircraft Spruce. If the company is a U.S. company, that helps. These companies often are kit manufacturers as well, so many of their parts come from local outlets.

Many European designs use parts not commonly found in the U.S. This has been a problem, especially with wear items such as tires and brakes. We'd avoid designs where any regularly-replaced items come exclusively from the company or from one foreign supplier. Some U.S. distributors of European LSAs have switched the parts they use or allowed substitution (see sidebar page 16) to deal with this problem. Many S-LSA parts are not built with the same robustness as certified aircraft. We have reports of seats and interior parts, seatbelts, strobe packs, landing gear legs, latches and electrical switches being weak points on many designs. Check these for wear before buying and find out where replacements can be gotten.

Of course, parts such as wheel pants or wings must come strictly from the company. Going with a larger company is a safer bet here. Naming names, we know that Flight Design, Gobosh, Remos and Tecnam are all strong in keeping a supply of company-specific parts in the U.S. Others may be as well. Jabiru USA assembles and paints the Jabirus in the U.S., so parts can be gotten out of their production stores.

You'll want to talk with owners too, because what seems simple might not be. Tim Adelman operates both Tecnams and Sky Arrows in a flight school. When one of the Tecnams had damage to its aluminum wing, the repair was made using readily-available metal--including building a new rib. When the composite wing on the Sky Arrow needed a fix, the fiberglass work was trivial but the cloth needed for the repair wasn't available in the U.S. and the company wasn't much help. A Sport Cruiser owner we spoke to needed a new gear leg, which the factory in Czechoslovakia sent. The "part" was an unfinished piece of fiberglass. It didn't even have holes drilled in it to attach to the airframe and wheel.

Adelman puts a good maintenance manual near the top of the list as a requirement for a good S-LSA. Any repairs that aren't specifically addressed in the manual must be approved by the manufacturer. That could be a serious hassle in both effort and aircraft downtime.

S-LSA owners have a maintenance trump card, however, that legacy LSA owners can't match. Any S-LSA can be converted to an E-LSA by requesting the change from the local FSDO. This makes the LSA an experimental aircraft, and now the owner can decide what repairs are legal and airworthy. While many owners wouldn't want to take on that responsibility themselves, it could free an LSA repairman or A & P mechanic to fix or replace the part your having trouble getting fixed. The catch is that once it's an E-LSA it can't ever switch back. E-LSAs currently can't be used for rental or other commercial operations (towing for hire is OK).

An interesting twist on this is that if an S-LSA manufacturer goes out of business and no group steps up to take responsibility for continuing support, such as issuing service bulletins, then all the S-LSAs of that make become E-LSAs automatically. This could be a serious trap for flight schools who have invested in one make of LSA for flight training. There is an exemption process for homebuilt experimentals to be used for rental and flight training (a 319H letter), but this has not been extended to cover E-LSAs yet.


The takeaway from this picture is that there are avenues to keep old and new LSAs flying. None are paperweights strictly because the manufacturer is gone and buried. It just may take more effort as an owner to get the parts you want installed and legally airworthy than you expected. Hedge your bet by making sure a solid support system is in place before you buy.

It's no guarantee, but it'll help.


There's a lot of confusion out there on how you make changes to the new, ready-to-fly LSAs, the S-LSAs. Here's the skinny directly from the FAA regulatory branch in charge of this area.

Any repairs or modifications to the aircraft that aren't described in the maintenance manual require a letter of authorization (LOA) from the manufacturer authorizing the work. So, it's the same process whether you accidently busted out a rear window and there was no mention of window repair in the manual, or if you wanted to upgrade the seats to leather and extra foam.

Find out what LOAs already exist for the aircraft you are interested in. This tells you several things. LOAs allowing a substitution of a U.S. tire for a European one is a clue that this is an issue, and a clue the manufacturer supports requests for changes. You'll also ger a feel from the letter as to how detail-oriented the manufacturer is. While it's good to have a manufacturer that's responsive to requests, one that's too liberal indicates a lack of engineering concern that we'd stay away from.

Existing LOAs don't give you automatic permission to make that change to your aircraft. You need your own copy of the LOA to pur in the aircraft logbook. The LOA does not need to have the aircraft N-number and can be a copy---so you can ger one LOA to cover several aircraft--but it should spell out the general details of the repair, and it must come from the manufacturer. Many manufacturers have stacks of commonly requested LOAs ready to go.

If no LOA exists for what you want to do, expect to provide some engineering details to the manufacturer. There's no standard form for this and, again, it's the manufacturer you're dealing with for most requests. That manufacturer may be separated from you by several time zones and a language barrier. We say most requests because some U.S. distributors have headed oft this problem by getting blanket authority for issuing the LOAs in certain areas. Avionics changes area common example. This shortcuts the process quite a bit. If you're looking at a used LSA, you'll want to make sure all of its applicable LOAs are included.



When a required part no longer exists and no one makes a replacement, the way out for legacy LSA owners (and anyone restoring an antique aircraft) is through what's known as an owner-supplied part. Unlike a manufacturer who must show identicality or get an STC, and get the authorization to manufacture the part (PMA), an owner can supply a part and get approval for the substitution from the local FSDO.

That sounds simpler than it can be in practice. The FAA sees four classes of substitutions here: minor repairs, major repairs, minor alterations and major alterations. A minor repair might include fixing a floorboard o trim piece with a roughly equivalent material. Since it's not structural or a control surface, it may be legal with a simple logbook entry. Major changes usually require submitting some engineering data to prove the change doesn't adversely affect the aircraft.

Citing a need to help owners with this process, the FAA recently issued AC 23-27 to give some guidance on what typically constitutes different classes and what substitutions are commonly done. This AC can't be used to authorize a change, but it can be used as part of the "approved data" to substantiate a request for a repair or alteration. Owners may also need to dig into AC 43-13, which is a bit of a tome on Inspection and Repair.


(+) Alteration/modification for S-LSAs is simpler than on certified aircraft.

(+) The FAA is increasingly flexible on modifications to legacy LSAs.

(-) Some parts for legacy and modern LSAs can be difficult (or impossible) to get, repair or fabricate.

(-) An unresponsive or out-of-business LSA manufacturer seriously complicates long-term supportability.


Wag Aero Group


Univair Aircraft Corporation

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Title Annotation:AIRCRAFT MAINTENANCE; light-sport aircraft
Author:van West, Jeff
Publication:The Aviation Consumer
Geographic Code:1USA
Date:Nov 1, 2009
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