Removed vaccum pump.. Hole in firewall.. Best way to "fill" this?

[BellyUpFish]

Best fix: leave that bulkhead fitting in the firewall and cap it with an AN cap.

Dan

That might be a plan. I'll have to reinstall it, but no big deal. I already ripped it out.

 

[Tom-D]

A random one from Lowes of questionable integrity from the get go that may or may not fit worth a crap is.


That's assuming it's not a total piece of crap with terrible tolerances, which it probably is, and that's assuming it perfectly fits the hole which it probably doesn't.


Just because the right fix is more work doesn't make it the wrong fix. One could ensure they weren't going to drill through anything. Would it take some effort? Sure.

You make large assumptions with no evidence the OP would except that shoddy work. and what happens when later the vac system goes back on, now you must contend with a bunch of rivet holes.

 

[Tom-D]

Best fix: leave that bulkhead fitting in the firewall and cap it with an AN cap.

Dan

that'll work too.

 

[Tom-D]

I was thinking originally about drilled an riveting a new plate onto the firewall, and posted that was the idea. I spoke with an A&P this afternoon and he thought that might not be the best idea. He said he rivets would simply melt away and the plate would come off. No idea if this is accurate or not, but it's just 1 of 6 opinions I've gotten from individuals the FAA found to be qualified to be paid to give that opinion.

When you patch Stainless steel you use monel rivets. they will not melt.

 

[kontiki]

Couldn't find my prev post on this. I must have muffed it up.

Fire wall gives you time to land the plane if you have an engine fire.

It's also a CO barrier in the event you have an exhaust leak.

The plug you found is probably designed to be no more than a cosmetic plug at best. Not even a fastener in it?

Is there a structural repair manual that describes firewall repairs?

I might be inclined to bolt on a small scab patch, using non cadmium plated hardware. Sealant might be a good idea.

 

[Henning]

You can also use a high temp sealant to stick on the patch or you could TIG it even.

 

[BellyUpFish]

Yeh, I'm not getting any welding going on. That's just a lot of extra headache when there are options that will work. For TIG to be effective, I'd have to totally clean the area on the firewall, and it's coated with some fire resistant paint, not sure what.

I think the options are:

A.) Simple plug
B.) Plate & Rivet
C.) Put the bulkhead fitting back in the plane and AN cap it.

 

[Tom-D]

Yeh, I'm not getting any welding going on. That's just a lot of extra headache when there are options that will work. For TIG to be effective, I'd have to totally clean the area on the firewall, and it's coated with some fire resistant paint, not sure what.

I think the options are:

A.) Simple plug
B.) Put the bulkhead fitting back in the plane and AN cap it.

Fixed that for ya.

 

[BellyUpFish]

Fixed that for ya.

LOL Thanks.. What don't you like about the plate and rivet idea?

I could always throw a plug and some 3M fire barrier caulk down. That stuff is supposed to last 4 hours in a fire.

 

[Henning]

LOL Thanks.. What don't you like about the plate and rivet idea?

I could always throw a plug and some 3M fire barrier caulk down. That stuff is supposed to last 4 hours in a fire.

You can also use it to glue on the patch, but the fitting is quickest easiest and cheapest and works fine.

 

[Skylane81E]

On an RV, I like the plug, assure a good fit, use a little fire resistant sealant and call it a day.

On a Certificated airplane you will have an STC or a Field approval for the modification that hopefully would give some type of guidence. If not you go to the SRM or the 43.13.

IF riveting a patch you loose some strength due to the extra holes and must assure that you use the propper rivets.

 

[Tom-D]

LOL Thanks.. What don't you like about the plate and rivet idea?

I could always throw a plug and some 3M fire barrier caulk down. That stuff is supposed to last 4 hours in a fire.

The extra holes, and the possibility of damaging some thing else making them, and if you were to use the right rivets you would be bucking them and be required to get a bucking bar behind the patch from inside the aircraft.

 

[flyingriki]

Since you've started this whole broo-ha-ha all over again on VAF - You should consider all the work Dan put in to test several sealants over there:

http://www.vansairforce.com/community/showthread.php?t=72087&page=4

starts down at post #38 or so.

 

[Let'sgoflying!]

Re: Removed vacuum pump.. Hole in firewall.. Best way to "fill" this?

That is contrary to FAA guidance given to A&P-IAs

I asked our fsdo mx inspector this, here is his answer:

"there is no set rule, in which logbook. The FAA considers aircraft maintenance records as one item, as defined in 91.417 (a) (b)"
(I realize you could take this to the highest faa court in the land to prove yourself right, but I am pointing out that even the faa disagrees with itself on this...as it does with many things!)

Tom, I know you are technically correct however from a practical standpoint, I bet if you looked at a hundred logs, if something is bolted to the engine you know a good many of those a/c are going to have it shown in the engine log. Not sayin' it's right....or even a good practice, but that's what people do. Even an engine o/h, properly many oh'd accessories should be in the airframe log...but guess where they end up.

 

[Tom-D]

Re: Removed vacuum pump.. Hole in firewall.. Best way to "fill" this?

I asked our fsdo mx inspector this, here is his answer:

"there is no set rule, in which logbook. The FAA considers aircraft maintenance records as one item, as defined in 91.417 (a) (b)"
(I realize you could take this to the highest faa court in the land to prove yourself right, but I am pointing out that even the faa disagrees with itself on this...as it does with many things!)

Tom, I know you are technically correct however from a practical standpoint, I bet if you looked at a hundred logs, if something is bolted to the engine you know a good many of those a/c are going to have it shown in the engine log. Not sayin' it's right....or even a good practice, but that's what people do. Even an engine o/h, properly many oh'd accessories should be in the airframe log...but guess where they end up.

Just sayin,, guidance is guidance, rules are rules, and in this case we have guidance and no rules.

Would it be reasonable to assume that if you installed a vac pump, and logged it in the engine log, then 6 months later removed the engine and used it as core, your new entry would go away with the engine log and your new vac pump would stay with the aircraft with no entry to say it was changed?

It's for that reason we get the guidance we do.

Now about a prop? remove it, the entry would go in which log (S)

 

[BellyUpFish]

Since you've started this whole broo-ha-ha all over again on VAF - You should consider all the work Dan put in to test several sealants over there:

http://www.vansairforce.com/community/showthread.php?t=72087&page=4

starts down at post #38 or so.

I had no idea I had started a broo-ha-ha. I figured, since this was going into an RV, I'd post over there as well to see what people flying similar aircraft thought.

The solution is in hand though. I picked up a 5/16 bolt, some lock washers, fender washers and a nut and will be installing it tomorrow.

Had I not posted at VAF, I would not have considered this idea. I guess it's a good thing to get broo-ha-ha's going.

 

[flyingriki]

I had no idea I had started a broo-ha-ha. I figured, since this was going into an RV, I'd post over there as well to see what people flying similar aircraft thought.

The solution is in hand though. I picked up a 5/16 bolt, some lock washers, fender washers and a nut and will be installing it tomorrow.

Had I not posted at VAF, I would not have considered this idea. I guess it's a good thing to get broo-ha-ha's going.

Focus, focus Fish. The point was the extensive testing done by someone on sealants-not the little tease that seems more important to you.

Isn't it interesting you get the best and most sensible ideas from the experimental crowd? Other than a couple rare guys, most the lousy and often scary work I've found on aircraft was done and signed off by A&Ps. And a couple of those thought they knew it all too. An I do mean scary......!

We've shaken our heads many, many a time looking at the dangerous conditions found under cowls and inspection plates. They hide behind government regulations. If you take off and find the issue later - it's your butt for flying a non-airworthy airplane. Now watch the argument over that! It's true and proven in the precedents.

I'd still check out Dan's excellent work rather than make fun of me, a better use of your time.

 

[BellyUpFish]

Focus, focus Fish. The point was the extensive testing done by someone on sealants-not the little tease that seems more important to you.

I am focused, well maybe not anymore, I picked up the requisite 5/16" bolt, lock washers, fender washers and nut. I'll get some 3M Firestopper tomorrow on the way to the field.

Isn't it interesting you get the best and most sensible ideas from the experimental crowd? Other than a couple rare guys, most the lousy and often scary work I've found on aircraft was done and signed off by A&Ps. And a couple of those thought they knew it all too. An I do mean scary......!

Which is the VERY reason I've started doing all the mx on our RV. We recently had an O-ring go out in the brakes and I figured, I work on everything else I own, might as well fix the plane to. Well, we found several things mechanic (no offense to those here) did we did not like. Most mechanics seem to just want to get the car, truck, plane, etc out of their space and on to the next thing. I don't let mechanic's of any sort touch something of mine, unless they HAVE to.

We bought the plane flying and I had no idea you could work on it without a repairman's certificate. Everyone we talked to said you could only do the same things you can do to a certified aircraft. Well, I've learned differently and now *I* am the mechanic on this bird.

I'd still check out Dan's excellent work rather than make fun of me, a better use of your time.

Wasn't trying to make fun. I was pointing out that, without having started multiple brou-ha-ha's, you most likely would not have posted what you posted, I would have never read the other thread and come to the conclusion that I should ditch the RTV and move onto something better. Thus am glad I started such a ruckus.

 

[flyingriki]

Gotta love a happy ending!

 

[BellyUpFish]

Gotta love a happy ending!

My personality doesn't do text well. LOL.. I always come off as a jerk or angry. I find myself in internet arguments uber-quickly. Lack of inflection. I have that, as my wife puts it, "loveable sarcastic nature."