[USA] FAA approved canopy crack repairs

Jim Britton

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Oct 15, 2010, 2:28:35 PM10/15/10

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Our trusty Grob 103 is undergoing an 'extension of life" inspection
(AKA 6000 hour inspection)
One of the issues is with minor repairs to its front canopy.
We have one small crack starting from the right rail, less than 2
inches in length and well out of line of sight.
The plan was to do the usual repair by stop-drilling then fixing with
'Acryfix'

The inpector is looking for "FAA approved data" or existing "guidance"
to allow a return to service with this fix.
Without this we will need a new canopy.

I am not looking for "we've always done it that way" types of
responses.
Anybody got any formal documentation that would satisfy the FAA that
this repair is allowed?

Thanks,

--Jim

lanebush

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Oct 15, 2010, 3:05:14 PM10/15/10

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AC 43.13 gives guidance on repairing acrylic windows and is FAA
approved. However, you will not like what you read. It requires
"stitching" up the crack with safety wire.

Lane
XF

Tony

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Oct 15, 2010, 3:06:28 PM10/15/10

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Jim,

Page 3-19 in AC 43-13B addreses repair to plastics:
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/list/AC%2043.13-1B/$FILE/Chapter%2003.pdf

Your mechanic should have a copy of this laying around the shop.
Seems to me on a small crack out of the line of sight stop drilling is
acceptable to the FAA.

Tony
-Not and A&P

Frank Whiteley

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Oct 15, 2010, 7:15:18 PM10/15/10

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On Oct 15, 1:06 pm, Tony <abcon...@gmail.com> wrote:
> On Oct 15, 1:28 pm, Jim Britton <jamesbrit...@yahoo.com> wrote:
>
>
>
> > Our trusty Grob 103 is undergoing an 'extension of life" inspection
> > (AKA 6000 hour inspection)
> > One of the issues is with minor repairs to its front canopy.
> > We have one small crack starting from the right rail, less than 2
> > inches in length and well out of line of sight.
> > The plan was to do the usual repair by stop-drilling then fixing with
> > 'Acryfix'
>
> > The inpector is looking for "FAA approved data" or existing "guidance"
> > to allow a return to service with this fix.
> > Without this we will need a new canopy.
>
> > I am not looking for "we've always done it that way" types of
> > responses.
> > Anybody got any formal documentation that would satisfy the FAA that
> > this repair is allowed?
>
> > Thanks,
>
> > --Jim
>
> Jim,
>

> Page 3-19 in AC 43-13B addreses repair to plastics:http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular...

>
> Your mechanic should have a copy of this laying around the shop.
> Seems to me on a small crack out of the line of sight stop drilling is
> acceptable to the FAA.
>
> Tony
> -Not and A&P

Section 4 Paras 3-40 c and d (pg3-23) would seem to apply to an area
as described by the OP. More on PS-30 and Weld-On 40.
http://www.altuglasint.com/expert/data/236

Give 10 minutes for bubbles to rise out after mixing the two parts
together and before application. A real expert can make the crack all
but vanish with proper application, sanding and polishing. IMVHO, a
glued repair is also much stronger than a drill stopped crack.
http://www.rplastics.com/weldon40.html

Frank Whiteley
Not an A&P, but have repaired canopy cracks using both Acrifix 192 and
methylene chloride two-part kit (in the UK).

lanebush

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Oct 16, 2010, 9:32:52 PM10/16/10

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On further inspection of AC 43.13 it does give guidance on repairing
small, out of the line of sight, cracks using stop drill holes and
acrylic glue. Anytime 43.13 gives appropriate guidance this is
approved data.

Lane
XF

uncl...@ix.netcom.com

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Oct 18, 2010, 9:33:20 AM10/18/10

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Except when 43.13 conflicts with manufacturer's information which
becomes the prevailing approved data.
UH