Zenith 601 XL and 650 grounded again...

[justin.schoeman]

Seems like the Zenith wing issues are finally reaching a conclusion:

FAA SAIB:
http://rgl.faa.gov/Regulatory_and_Guida ... enDocument

AMD (factory produced Zodiacs):
http://www.newplane.com/amd_downloads/S ... 202009.pdf

And lastly, a very informative Q&A with Chris Heinz (Zodiac designer):
http://www.zenithair.com/zodiac/xl/data ... ntz-1a.pdf

Seems like all the factory produced models are grounded until both wing spars are upgraded, and a few other changes are made. In a quirk of US law, it seems only the manufacturer can ground planes, so amateur built examples are not grounded, although the FAA SAIB says that it is a legal requirement for aircraft to be airworthy before flight - and then strongly hints that they don't consider the aircraft airworthy unless the mods are performed...

The Q&A with Chris Heinz is very interesting. He points out that all the modifications are precautionary. As the design stands, it meets all the required structural limitations - BUT there is vary little (if any) additional safety margin. I think designers like John Thorpe would love this design - the wings fail at the designed limit load, with not 1 gram of extra mass added for a little extra margin. Seems the FAA doesn't share their sense of design elegance though, and requires a little extra fat built in.

Seems the long drawn out string of groundings is finally ending with a conclusive response from the FAA and Zenith.

[Rudix]

Thanks for the info Justin!

At least this should be the end of this saga, I am just glad I do not have a XL, replacing the spars does NOT sound like fun

Fly safe,
Rudi

[justin.schoeman]

Yup, fortunately the HD and HDS models still have excellent safety records. No in flight structural failures (except for canopies opening - but mostly these are builder mods).

I would hate to own a factory made 601XL - I hear AMD is quoting 80 hours labour + $300 parts .

Personally, if I owned a 601XL, I would just install anti-servo tabs, so that you have to be Herculese to even pull 3G...