160 HP engine and wood spars

BB57

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Feb 20, 2020
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That the rub. Note 13 only addresses the "following changes apply" to 7-1545 wings and all of those changes are gross weight and CG related.

That's short of saying that a 160 hp aircraft must have metal wings.

There's also no relation between metal wings and installed horse power other than if there is a GW increase. Again, Vne is unchanged with metal wings, fuel capacity is unchanged and the only items that would structurally make a difference are in the fuselage.

So it's ambiguous at best.
 

Kmcaero

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Jun 3, 2018
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Your my new Bestest Friend BB57!! you have given some very good information here to help my claim. Might have to call on you again if that's o.k.?
I have seriously looked at the 180Hp STC and have flown them, performance is definitely as expected. I would really like to do that but I am trying to stay behind the point of no return cost wise on this project and look for a Scout for my next!
 

BB57

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Feb 20, 2020
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152
Your my new Bestest Friend BB57!! you have given some very good information here to help my claim. Might have to call on you again if that's o.k.?
I have seriously looked at the 180Hp STC and have flown them, performance is definitely as expected. I would really like to do that but I am trying to stay behind the point of no return cost wise on this project and look for a Scout for my next!
Sure feel free to post questions. However, my experience is limited to the vagaries and pitfalls of reg writing.

Given how ACA jumped on the wood wing spar SB and AD, when there were to my knowledge only a couple failures (and all on aircraft with over turn or wing tip strike histories), I get the feeling their intent with 125 and Note 13 was to strongly imply that metal spars are required, so that they'd sell more metal spar wings.

That said, if it isn't expressly forbidden, then it is permissible, and any ambiguity will go against the author. The fact remains that note 13 is all about CG and gross weight limit changes. If ACA really wanted to expressly require metal spar wings for 160 hp and 180 hp installations, they easily could have made Note 14 specifically state it as a requirement. But they didn't. Most likely because there were already wood wing sparred 160 hp and 180 hp Citabrias out there in the wild being operated safely every single day. For example, I flew a 180 HP 7BGBC Citabria in 1985, almost a decade before the metal 7-1545 wings even existed.
 

Bob Turner

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Apr 4, 2018
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I agree - always interpret ambiguities in your favor. A lot of aircraft folks do the opposite.

That said, let me play devil's advocate: what do you think a lawyer would say "outfitted per" means, in this context?

If "outfitted per" can be considered ambiguous (a 160 hp installation is "outfitted per" notes 13 or 15 whether or not it has items specified in notes 13 or 15) then you are home free.