Repairing Crack in Plane Window

Chrisgoesflying

Chrisgoesflying

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Chrisgoesflying
My plane has a small crack, maybe 2 inches long on the side window. It's been stop drilled. However, it's a solid crack and when flying, air is coming through it. Nice right now in the summer but I'm afraid I won't like it as much in the winter. So, how do I seal that crack? Any suggestions with product names or better yet, Amazon links? Or do I have to bite the bullet and get a new window for $600 plus a lot of $$$ to get it installed?
 
You can replace it yourself under preventative maintenance. The side window is not $600.
 
Chrisgoesflying said:
So, how do I seal that crack?
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If your AME is okay with it, get you a piece of equal thickness acrylic and cut out a repair doubler to cover the area of the crack. Pick up some PS-30 or Weld-On adhesive and glue the doubler repair over the crack area. You'll need to figure a way to keep pressure on the doubler until the adhesive cures. Details can be found in FAA AC 43.13-1b Chapter 3.
 
Chrisgoesflying said:
It's pretty darn near $600 and probably more after shipping: https://www.knots2u.net/pilot-side-window-assembly-with-frameless-vent-gla2258-lh/
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There are other aviation window suppliers. Plus, you can to the install yourself as long as it's not the windshield. But warning - it can be messy because you've got to clean the old crap first then install new with new adhesive.

I did 4 side windows last year in the cherokee for $1200. The pilot window with vent was $600, the other 3 were $600 total. Which window, which airplane?

https://lpaero.com/

https://www.glapinc.com
 
murphey said:
There are other aviation window suppliers. Plus, you can to the install yourself as long as it's not the windshield. But warning - it can be messy because you've got to clean the old crap first then install new with new adhesive.

I did 4 side windows last year in the cherokee for $1200. The pilot window with vent was $600, the other 3 were $600 total. Which window, which airplane?

https://lpaero.com/

https://www.glapinc.com
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It's a Piper Comanche. I don't think I would trust any window to stay in place if I install it lol.
 
I’m not certain if this is a good idea or dumb one, but it’s reversible. Take painters tape and lay it on either side of the crack and on both ends, about 1/8” all around the crack. Take clear silicone and spread it thinly over the crack. Remove the tape and let it cure.

An irreversible option is to use the clear acrylic glue mentioned by a couple of our friends above, using the method I described.

Not necessarily a certified or A&P approved repair. Flame on.
 
455 Bravo Uniform said:
Not necessarily a certified or A&P approved repair.
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Would it be "approved" if my mechanic is okay with it? I can't imagine flying with a crack (which he thinks is fine and doesn't warrant a window replacement) is better than flying with a repair as described above.
 
Chrisgoesflying said:
Would it be "approved" if my mechanic is okay with it? I can't imagine flying with a crack (which he thinks is fine and doesn't warrant a window replacement) is better than flying with a repair as described above.
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My disclaimer was only that I wasn’t sure if it needed to be approved or not.

It sounds like your A&P addressed the issue from worsening and is OK with its existence.

Here’s my take: would it be ok regulatorily to pull a 2.5” piece of Scotch tape off and lay it over the outside or inside of the crack? Probably. What about clear packing tape? Probably. What about an EAA or Osh sticker? Again, probably fine. How about a thin strip of clear flexible silicone? Acrylic glue? I don’t think you need approval, but it’s not my ride.
 
I would use some of that UV curing miracle plastic fix they sell. I fixed a plastic water cup a couple of years ago, it's still fine. But not pretty.
 
I, uh...have a friend who has a crack in their pilot's side window. It's vertical and all the way through the pane, about three inches back from the fore-most corner, meaning that there's about a 3x3x3"-ish triangle of plexiglas separated from the rest of the pane. Not sure if that's comparable to your situation or not.

The plane came to...my friend...that way so it had been there for some time already, and it survived the 1000-mile repositioning flight after he bought it, so it didn't seem like the window was about to blow out and he was reluctant to replace the whole window. The A&P reluctantly offered to glue an acrylic doubler over the crack. Not sure that's an approved repair, but...my friend has been flying it for almost 15 years and 1000 hrs now with no further issues.
 
The nice thing about using some silicone caulk is that it is flexible. The window cracked due to stresses. A hard repair may end up cracking again.
 
455 Bravo Uniform said:
My disclaimer was only that I wasn’t sure if it needed to be approved or not.
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What I've found is it depends on what the planned final action (replacement or permanent repair) for the crack determines what is done initially. If replacement is the plan then basically anything can be used with a simple stop drill the only requirement for most single cracks. However if the plan is to apply a permanent repair like mentioned above then you'll find a number of those temporary actions can and will affect the quality of the permanent repair. My normal route was if it will be a replacement then I would stop-drill and apply a clear speed tape or polyurethane tape around the crack area. If a repair is planned then I would stop drill initially then schedule the permanent repair as soon as possible to ensure a good final result both optically and structurally. You'll also find these type window repairs are considered minor so no "approvals" needed but whatever method used needs to be "acceptable" and have a logbook entry which a pilot can do under prevent mx.
Jim_R said:
The A&P reluctantly offered to glue an acrylic doubler over the crack. Not sure that's an approved repair,
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Its an acceptable minor repair. No approval needed. However when there is excessive damage the recommendation is to replace which is probably why the mechanic hesitated. But a full length permanent repair as stated is perfectly legit.
 
Chrisgoesflying said:
It's a Piper Comanche. I don't think I would trust any window to stay in place if I install it lol.
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I just replaced both rear windows w/.25" thick this weekend - it's not hard. Getting the screws started going back together was the hardest part. I did have to cut the new ones to fit. Did you check w/Webco on price?
 
You can replace your side windows but fairly certain that the front windshield is structural and has to be done by an A&P.
 
AC43.13-1B has all the stuff on aircraft window repair, starting on page 3-19.

If it was my airplane, I would carefully enlarge the stopdrill hole with a Unibit (NOT the common drill bit, unless it has been ground to the right profile as per AC43-13, as it may make the crack worse), and use a #6 brass screw cut to the right length, and a brass nut, with nylon or Delrin washers under the screw head and nut, to close the hole and discourage flexing of the crack. Don't make the nut too tight or additional stress will be put on the plastic.
 
The windows aren’t that old. Maybe 10 years or so at the most and the plane has always been hangared. The crack on the pilot side is because the previous owner leaned on it and it cracked. It’s a small crack. Total length is shorter than my thumb. But, air does come through which is kinda nice at 80 oat but probably not so much at 10 oat.
 
Stop drill with 1/8" bit, put acrylic adhesive in hole, flex a bit to wick into crack, then insert 1/8" diameter acrylic rod in hole. Let dry, sand flush, then polish with rubbing compound. Nearly invisible. Test on a piece of scrap lexan to show your A&P the results.
 
My preference is a hot welding rod rather than a drill.

I hate the cracking noise.
 
Ed Haywood said:
Stop drill with 1/8" bit, put acrylic adhesive in hole, flex a bit to wick into crack, then insert 1/8" diameter acrylic rod in hole. Let dry, sand flush, then polish with rubbing compound. Nearly invisible. Test on a piece of scrap lexan to show your A&P the results.
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Nit-picking. Airplane windows are usually acrylic. Lexan is polycarbonate. Different stuff. If doing a practice session use the material you'll be working with.
 
Stewartb said:
Nit-picking. Airplane windows are usually acrylic. Lexan is polycarbonate. Different stuff. If doing a practice session use the material you'll be working with.
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That ain't a nit-pick. It's a serious distinction you made there. Like you say, use the same stuff for the test. The glues for acrylic won't work on polycarbonates.

Lexan can be drilled with almost no concern for cracking. It can be bent and folded like sheet metal if it's thin enough. It can be cut with shears, if it's 1/8" or less. The stuff is so much like soft metal it's weird. But if you heat it just a bit too much you can get lethal fumes off it.

It will crack if it's used as a window or windshield if it's restrained too firmly. It needs to be able to expand and contract with temperature changes. I had it in my Jodel, and it started cracking around the mounting screws because I had holes that were only a hair bigger than the screws. When I made a new windshield I drilled the holes oversized and used nylon washers under the screw heads so that the material could slide a little. No more cracks.
 
Ed Haywood said:
Stop drill with 1/8" bit, put acrylic adhesive in hole, flex a bit to wick into crack, then insert 1/8" diameter acrylic rod in hole. Let dry, sand flush, then polish with rubbing compound. Nearly invisible. Test on a piece of scrap lexan to show your A&P the results.
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FYI GA aircraft windows are typically acrylic not Lexan. Lexan is polycarbonate. WAY different stuff.
 
We use aircraft windshield company who makes the windows on the spot in Los Alamitos ca.

Hmmm yeah no on the $600.

I wish all windows were as easy to replace as a Cherokee or Comanche. Can you say Mooney / Piper Apache / pick your jet?


Sent from my iPhone using Tapatalk
 
IPS Weld-On #16 is supposed to work well on aircraft acrylic window cracks like you describe. I’d back it with clear packaging tape to keep it from running.
 
Some of the older A&Ps may remember this.. Didn’t there used to be an approved stop drill & baseball stitch repair method? I’m reaching WAY back here but definitely remember seeing it work well. Not the prettiest but it worked.
 
Scroll about halfway down:

www.aopa.org

Opinion: Real-life breakdowns

Every aircraft owner dreads a mechanical breakdown while away from home on a trip. In the five and a half decades that I have owned an aircraft—I bought my first airplane in 1968 and have always flown lots of long trips—I’ve been the victim of such mechanicals more times than I have fingers.
www.aopa.org
 
Bell206 said:
If your AME is okay with it, get you a piece of equal thickness acrylic and cut out a repair doubler to cover the area of the crack. Pick up some PS-30 or Weld-On adhesive and glue the doubler repair over the crack area. You'll need to figure a way to keep pressure on the doubler until the adhesive cures. Details can be found in FAA AC 43.13-1b Chapter 3.
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I did this a couple years ago on a J3. I used larger sized rare earth magnets (from Harbor Freight) to hold/clamp the pieces together.
 
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