brien23
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Cessna 172M firewall damage right side above oil cooler cowling mount to firewall tore loose pulled out, also crack in firewall. Has anyone seen this before, would not have expected damage in this area.
A photo would help.Cessna 172M firewall damage right side above oil cooler cowling mount to firewall tore loose pulled out, also crack in firewall. Has anyone seen this before, would not have expected damage in this area.
My bad, will post picture soon.A photo would help.
A local FBO bought a new 182 firewall from Textron recently. $40K! Yikes.
Did this happen in one landing? or is it accumulative?Cessna 172M firewall damage right side above oil cooler cowling mount to firewall tore loose pulled out, also crack in firewall. Has anyone seen this before, would not have expected damage in this area.
Yep, seen it on a Cardinal. Plane was a hangar queen for weeks after that. What a mess to fix. (Not that I had anything to do with breaking or fixing, btw.)Rather common, one bad landing is all it takes.
Can you install a stainless patch on top of the damaged area ? Sounds like there was a poor doubler on initial install.
Can you install a stainless patch on top of the damaged area ? Sounds like there was a poor doubler on initial install.
Firewall is structure, It will be a major repair, using the structural repair manual as data.You guys should read before posting things like "nosegear damaged firewall and it must be replaced." The OP has a cowling shockmount bracket torn out just above the oil cooler. The 172M does exactly that and it just needs a stainless patch and the bracket reinstalled. I've done those.
They tear out because the bracket flexes the firewall there. It's a weak spot. The other side will be cracking too.
are you certain that this SRM applies to the 172 in question?Why would you say that?
Here's Cessna's take on repairing a 100 Series firewall. Whether it becomes a major repair will depend if the final repair meets the requirements in 43 App A(b):
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Firewall is structure, It will be a major repair, using the structural repair manual as data.
this area is a real PITA to work, unless you are a contortionist, it's easiest to remove the instrument panel to get to the area.
This is where owner produced parts start looking very good. I can't imaging a firewall is *that* complicated to scratch build.
Ever worked with stainless? Not much fun at all. And if the old firewall is all bent/torn/distorted, what do you use for a pattern?
The tolerances matter. Getting it a little small will result in unacceptable rivet hole edge distances. And measuring another 172 with all the stuff on the firewall would be fun indeed.I have worked with stainless. There are a couple of custom fabbed (by me) parts on my RV-10 that are stainless. As far as dimensions, either hammer the original flat and duplicate it or go measure another C-172. I can do a lot of fabrication for $40K. Besides, it isn't like missing a firewall dimension by 1/32" or whatever tolerance you can achieve in your garage workshop will matter.
The tolerances matter. Getting it a little small will result in unacceptable rivet hole edge distances.
It won't fit at all, even for drilling, if it's oversize. It's inset back from the edges of the fuselage skins, against formed angles riveted to the skins. You'd have to trim, fit trim some more. And you'd need to make sure that the fuselage sides haven't been distorted by whatever forces ruined the firewall in the first place, or the new one would just fix those distortions permanently in place, which would dislocate the engine mounting points and a bunch of other stuff.You can screw it up a bunch of ways. But for $40k, I'm willing to screw it up a time or two if that's what it takes to get it right. Any decent IA, A&P, or homebuilder with sheet metal experience could do it. Honestly, I don't see fabricating a firewall as that big of a deal. Referencing the problem you threw out there, you fit the firewall with oversized flanges, drill the firewall to the fuselage, mark the flanges for trimming, pull it off and trim it. Sheet metal isn't that hard.
Sheet metal looks easy until you get into it as a job and run into way more complexities than you expected. Been there, done that, both as a homebuilder and licensed mechanic.
Good pictures, turn it in to the insurance company, it should easy total the aircraft, then that POS 172 can go way.
And the usage is showing.Harsh man... C'mon Tom, giver her some love. That grand 'ole lady has trained quite a few PPLs in her day huh?
Yes. But as mentioned above, can be a bit challenging to work the other side especially if there is additional interior damage.Has anyone seen this before,
This guy has an interesting page https://www.facebook.com/FAADER/?__...In7JkqgLsktkvGS5pJnU4bXC98GsAcbtWHcMmpx40GhFE
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