Zenith 601...2 questions

We haven't got that far yet, but it is N-numbered and has about 100 hours of flight time. I don't know yet why the hours are so low.

But to the question...what is a reliable way to visually confirm the mods have been made? It's clear the current owner is not a good source of info in this regard.
 
We haven't got that far yet, but it is N-numbered and has about 100 hours of flight time. I don't know yet why the hours are so low.

But to the question...what is a reliable way to visually confirm the mods have been made? It's clear the current owner is not a good source of info in this regard.

Looks to me like the doublers on the rear spar should be visible along with the rivets that attach the skin stiffeners, the thicker wing mount doubler in the fuselage and the aileron balance (that should be real easy to spot).
http://www.zenith.aero/profiles/blogs/installing-the-upgrade-package or https://www.youtube.com/playlist?list=PL6F59BA3FF60FC8EA

100 hours might not be that low for a hobby flown homebuilt. My ride has about 600 hours on it since it was first flown in 1998.
 
@Capt. Geoffrey Thorpe has it right. The two easiest ways to quickly tell if the B mod has been done is to look for the doublers on both sides of the fuselage at the forward area of the cabin and the aileron mass balance arms at the outboard ends of both ailerons. Of course it's still no guarantee the complete package has been properly installed; that can be determined by a more complete inspection.

Here's the doubler on the port side of my plane:
B Mod Doubler.jpg

I don't have a photo of the aileron mass balance, but here's the drawing showing the installation. It's really easy to see by standing at the wingtip and looking at the square aluminum extrusion extending into the wing from the outboard end of the aileron.
B Mod Aileron Mass Balance.jpg

EDIT- I took a photo of the aileron mass balance lever arm installed as part of the B modification kit.
Aileron Mass Balance Weight Lever Arm.jpg
 
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Here's a link to the web page where Zenith demonstrates the installation of the wing mod. I believe it's a strengthening of the spar & attachment point?

http://www.zenith.aero/profiles/blogs/installing-the-upgrade-package

It may be more useful to builders than pilots, but interesting just the same to see what was done. Many pages to click through and videos to watch in there.
 
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