Fin Rib Kits

[Sherman]

Re: Fin Rib Kits

--" you will have a high likelihood (I'll venture to say 70%+ over the life of the aircraft) of developing cracks if you don't have that last SB applied (double row of rivets)."

Important word here is LIFE of the aircraft. I am not yet at 1300 airframe hrs.

So Glenn, Jim: any info about 'Time on Airframe' these cracks have appeared? 1,000 hrs; 2000 hrs, 3000 hrs--etc; or if 'speed flown' is an issue??

Sid and I were talking about this when we went flying together in May. Don't have a full row of double rivets, but do have double rivets at the front of the tail fin.

Jim: This is absolutely fantastic that you have a safety improvement for us; as Cactusair stated, a pic of the two factory (CAC) kit mods 'rivets appearance on the tail would be helpful'.

I've had this Commander since '92 and know the SB's required WERE complied with. My previous Commander had the SB's complied with in March 90 (TC 13040) and when I bought my plane Bill at CAC confirmed that THIS COMMANDER had the kits installed 'after my 1st plane'. It was painted in '92, so based on the info here- 'which kit installed' needs further research.

Related, Someone mentioned the factory (CAC) logbook entries in the early 90's. My confirmation is on a Commander Aircraft Weight & Balance sheet. MY 1st logbook started when the N112HT was created vs the previous ID (Long unrelated story).

Jim- I also 'need to be interested' in a kit. Guess many are waiting for a cost: Kit and time involved.

 

[bradmc]

Re: Fin Rib Kits

The kit that CAC supplied was the double rib and some documentation for install.

It's possible that the black root seal could be hiding the upper row of rivets.

 

[Frank]

Re: Fin Rib Kits

Here a couple of pictures. You have to zoom in to see the rivets. There are 11 rivets as Jim mentioned in his post in the 2nd row. (Sorry about the view but I think you can see where the rivets are).
The first row is just below the black rubber and the second row is at the top of the blue stripe.
Second picture is the inside of the tail. According to my logs the work was completed by the factory in 1992.

Hope the above helps

 

[gmores]

Re: Fin Rib Kits

So Glenn, Jim: any info about 'Time on Airframe' these cracks have appeared? 1,000 hrs; 2000 hrs, 3000 hrs--etc; or if 'speed flown' is an issue??

Not that I've ever heard of Sherman but as a group we've never tried to gather that type of data. Plus some (like my 112) had the B kit installed prior to finding cracks so there is no data point.

Jim probably has a much better sense of it just given the sheer number of Commanders that he's worked on. Carl Gull would be a good resource also. I'll make a note to ask him about it the next time we talk.

 

[milojevicp]

Re: Fin Rib Kits

Hi Dan,

The entry in the log book you described is likely the "A" kit (horseshoe) repair. Shortly after this method was made available there were still cracks being discovered in other parts of the rib, and then the "B" kit was designed and made. The B kit has the obvious double row of rivets.

All the best,

Pete

 

[DKrueger]

Re: Fin Rib Kits

HELP, HELP, HELP...........


There is a children's book titled; "Alexander and the Terrible, Horrible, no Good, Very Bad Day". It's now changed to Dan.

First, got to the hangar to check some items we've been discussing and realized immediately upon rolling the door open that i'd left the fuel selector in the wrong position. oops

Second, after my last flight I was playing with my Garmin 430W to check a couple new items. I forgot to turn off the battery master and have killed the battery.

Lastly, (and the biggest item) I used Jim Richards PDF for inspection of the fin rib and discovered the following (see photo's). I am grounded until a solution is found. Any help will be greatly appreciated.

I am still puzzled how these were missed during the pre-buy/annual done prior to purchase, but that another issue.

 

[DKrueger]

Re: Fin Rib Kits

Oh BTW Frank was correct, the 1991 entry in my log was for the forward fin attachment kit. Ugh......the joys of ownership.

 

[wab003]

HELP, HELP, HELP...........


There is a children's book titled; "Alexander and the Terrible, Horrible, no Good, Very Bad Day". It's now changed to Dan.

First, got to the hangar to check some items we've been discussing and realized immediately upon rolling the door open that i'd left the fuel selector in the wrong position. oops

Second, after my last flight I was playing with my Garmin 430W to check a couple new items. I forgot to turn off the battery master and have killed the battery.

Lastly, (and the biggest item) I used Jim Richards PDF for inspection of the fin rib and discovered the following (see photo's). I am grounded until a solution is found. Any help will be greatly appreciated.

I am still puzzled how these were missed during the pre-buy/annual done prior to purchase, but that another issue.

Well, it sounds like you used up the "bad things happen in threes..." for this go round. Sorry about your tail.

 

[jrichards]

Re: Fin Rib Kits

Hi Dan,

Yes, that's the condition. When the tail is apart for the repair, we can advise your mechanic how to check for related subsequent conditions in the stab aft attachment that can develop after the cracks have formed and flown for some period of time. It's best to just go in once and be thorough with the inspection and repair.

Our first installation of the new kit has been successfully completed, I'll post pics on Monday. It went very well. We are ready to start on #2, now waiting at my shop, and should be ready in about 2 weeks to start fabricating parts to order. There are no more tooling/fab hurdles, we are just polishing up the drawings and procedural stuff for FAA approval.

Jim

 

[DKrueger]

Re: Fin Rib Kits

Scary to think that I've been flying this around probably since I purchased it last November. So I am grounded until your kit is ready or are there any of the old Commander kits floating around. Jim, I'll call you Monday to discuss my situation.

 

[jrichards]

Re: Fin Rib Kits

Hi Dan,

I look forward to speaking with you Monday. We should be able to fab you a parts kit about as fast as your mechanic can get the plane in and do the disassembly to get ready for it. Since we don't know yet how many are interested in a special initial offer of these kits, we may just have to give you a price based on an initial run of 5 or 10, subject to a rebate if we can get that number up to 20ish where the numbers start to work a lot better for everyone. I'll try to frame some numbers for you on Monday.

Our call for any remaining CAC 56B / 12B kits in May only got one response, and that owner graciously loaned us his kit for reference. I would like to trade him a new kit for it, and keep it on hand for reference, but that is up to him. Keep in mind, the new Aerodyme kit puts the airplane in a 114B/TC configuration. This is how it stacks up:

56B / 12B CAC Kit: The rib gets sawn off and remains in two sections.

Aerodyme Kit: Both the rib and doubler are new and whole, just like all the 114B/TC were built by CAC.

Jim

 

[atjudge]

Re: Fin Rib Kits

Dan: I was at the Commander Factory two years ago when cracks were found in my "Horseshoe" repair. Both Carl and Dave said I now had 150 hours to fly until a fix was required by the Service Bulletin. It was both their opinions that the aircraft wasn't "unsafe" to fly, So I fly it home. A week or two later I flew it back to have the work done. Weather you want to fly it or park it is up to you.

 

[DKrueger]

Re: Fin Rib Kits

Some additional photo's of the tail. Someone asked if he SB kit had been installed, the answer is I don't believe so. I can't find it mentioned in the log anywhere. Maybe from these pictures someone can tell.

 

[DKrueger]

Re: Fin Rib Kits

One more.......

 

[gmores]

Re: Fin Rib Kits

Sorry to hear about your find Dan, but also glad you found it. It sounds like Jim will be able to take care of the situation for you.

 

[Frank]

Re: Fin Rib Kits

Dan -Here are some more photos of my 1976 Commander tail and hopefully they are better than the others I posted. I took these yesterday.

You can see the top row is below the black rubber same as yours.
My 2nd row is mostly in the blue stripe.

 

[FS]

Re: Fin Rib Kits

Maybe from these pictures someone can tell.

Yeah. No. There's no evidence in the pictures you posted that any of the fin rib SBs have ever been installed.

 

[KikoandPat]

Re: Fin Rib Kits

Is there a document outlining the inspection? 77J's annual starts Wednesday and a good time to check this one out.

 

[DKrueger]

Re: Fin Rib Kits

Pat

In an earlier thread Jim Richards posted a PDF file outlining the inspection. It's very easy and only takes minutes. If you do a search you should find it, I can remember the title, it stinks getting old.

 

[wab003]

Re: Fin Rib Kits

there is also information contained in the SB's