FAA Issues SAIB for MLG Tie Struts

[barnstmr]

I just got this

[Robert Lees]

Re: FAA Issues SAIB for MLG Tie Struts

Thanks, Terry...we knew it was coming. I'll circulate it here in the UK.

Of note, it says: "At this time, this airworthiness concern has not been determined to be an unsafe condition that would warrant airworthiness directive"

Edit: for reference, here's the original 1978 Service Bulletin: Page 1 Page 2

[Forrest Barber]

Re: FAA Issues SAIB for MLG Tie Struts

I will comment later this afternoon, have to go fly I will call Andy on Tues. ; The B tie strut is the only one addressed, I agree that all should be inspected, but they are not built the same.
The B strut can not be "removed" the whole landing gear must be removed. ( Only if a problem is detected by the initial inspection). Apparently they did not realize that it is welded at the top... More when I get back this afternoon. bye thanks for the heads up.

[skip]

why the lower bolt?

When I recovered my gear a couple of years ago I was curious about the design of the tie strut.
Why was it welded at the top and bolted at the bottom?
It can't rotate around the bolt (being welded at the top).

What was the engineering idea behind the design of weld at the top and bolt at the bottom?
Why not weld both ends, or bolt both ends?

Always wanting to learn a little bit more of that engineering stuff...
Thanks in advance for any enlightenment.
Skip
BC12-D-4-85, N34237, SN 7700

[Forrest Barber]

Re: FAA Issues SAIB for MLG Tie Struts

There can be a slight rotation at bottom, kind of like the rear stab attach bolt used to be horizonial then went to vertical. The only failure known in that area was an F-19 that sheared off the forward tube on left side, he made it to the ground okay and then had to clean the seat cushion.

The other reason is for easy replacement of the tie strut, prop up ship, remove bolt, cut off top of strut 30 degrees 4 in down, use inside splice method and check distance, rebolt and weld her up.

Back to this SAIB : On September 19, 1978, Taylorcraft Aviation Corporation issued Service Bulletin (SB) No. 78-001 to include procedures for inspecting the MLG tie strut, PN B-A51, ensuring the factory drain hole is open, and drilling a drain hole if none exists. The factory drain hole was located either at the center of etc...
Lots of ships had hole painted over or was missing.

Notice this is the PN B-A51 The SAIB then discusses a A-530 strap.
The B-A51 is used on all "B" models and includes all the TC 1A9 ships .
The A-530 was on the A Models only. they are basically the same , A model is smaller.
Then we have the following from the SAIB :
If rust particles or debris are noted, or there is any question as to the integrity of the MLG tie strut, do the following inspection procedure:

1)Support and shore the airplane as necessary, and remove the MLG tie strut for further inspection. The 696, 699 & 700 ships along with the 1A9 ships cannot be "removed" IT is welded at the top of the landing gear. NOW the Tandem ships TC 746 can have the tie strut removed but it is NORMALLY a sealed strut and may not be affected by water freezing like the other ones.
I will contact Andy on Monday and discuss the issues. In the MEANTIME ; please inspect all tie struts as they should have been done each Annual . Tap, Tap , Tap needs to be done many places on these older aircraft....
Waht a great day to fly in OHIO.

[Robert Lees]

Re: why the lower bolt?

When I recovered my gear a couple of years ago I was curious about the design of the tie strut.
Why was it welded at the top and bolted at the bottom?
It can't rotate around the bolt (being welded at the top).

What was the engineering idea behind the design of weld at the top and bolt at the bottom?
Why not weld both ends, or bolt both ends?

Always wanting to learn a little bit more of that engineering stuff...
Thanks in advance for any enlightenment.
Skip
BC12-D-4-85, N34237, SN 7700

The bolt at the bottom is also there to attach wheel spat hardware (whether this was the reason for the bolt in the first place, I know not, but it makes sense).

Of more significance, perhaps, is why was it not a sealed strut? If I were replacing mine, that's what I'd do.

[Forrest Barber]

Re: FAA Issues SAIB for MLG Tie Struts

A few made it 73 years with no problem, just proper maintenace. Kind of like Proper Tea ah what! . Actually the wheel "spats" were added rather quickly and I am sure the bolt helped..... onward and upward.
We are doing a 1941 Cub with 85 HP; increased Gross Wt., no nose tank, big wing tank, big landing gear, new battery location, Beech Roby prop, closed cowl, Pa-18 tail surfaces, etc..... I think we will have about 10-12 STC's. My hands are tired from typing and writing. Bye the way the WACO 9 start up last Sunday came to a quick stop when the tank leaked at only 5 gal.... Does any one know what it takes to pull the 35 gal nose tank on a 1925 WACO 9 ....... you about have to take the top wing off.
Frank did it alone and we got the tank to another fabricator on Tues... Off into the Wild Blue one more time today.....

[cvavon]

Re: FAA Issues SAIB for MLG Tie Struts

Gang i had extra left gear leg so i cleaned it and took a photo of the drain hole
chuck

[TMc]

Re: FAA Issues SAIB for MLG Tie Struts

Hi all,
I'm an A&P that has been taking care of a '41 BC-65 for a friend in return for using it to get my Pilot's license.
About a month ago I took a close look at the tie struts and noticed there was no drain hole on the left tube and a two holes in the right (one filled with a screw and one showed signs of rust). I tapped the tubes and they had a dead sound as compared to the lift struts and other landing gear tubes. I drilled a hole in the left tie strut, and sure enough, probably 3/4 cup of rusty water came out. It didn't take long to make the decision to ground the airplane for repairs.
Soon after finding these problems I searched this forum and found the Airworthiness Concern and older Taylorcraft Service letter regarding drain holes, which made the choice to replace both tubes more concrete.
I removed the landing gear and am having a good welder replace both tie struts with replacement tubing from Wicks.
No pictures of the insides of the tubes yet, but will for sure put a good report together and send it to the FAA per the Airworthiness concern bulletin. I will also post my findings here- I'm sure I'll have some questions on bungee replacement-I'm new to Taylorcrafts. This forum is a great resource!!
Tom

[Forrest Barber]

Re: FAA Issues SAIB for MLG Tie Struts

Welcome aboard, please share all findings. This is a very important area for proper maintenace. You can go directly to me at taylorcraft.neo.rr.com what is ser# & n number. Does paperwork show any replacement of gears in past...

[TMc]

Re: FAA Issues SAIB for MLG Tie Struts

Update on my tie struts;
I removed the landing gear legs and an experianced restorer (Addison Pemberton) inspected them by tapping them with a punch and hammer. Turns out only one small soft/rusty spot was found on the lower RH tie strut (the side without the standing water in it btw). I decided to replace the lower 30" of the strut with new tubing.
I now have the landing gear repaired and need some help about how to approve it.
The replacement tubing is slightly larger than the original tubing (which is unavailable) and the new tube I.D. matches the O.D. very closely. I simply fabricated the lower attach point and welded it on the new tube then slipped the new assembly over the old tubing, inserting the old tube about 4.5", splicing it approximately 6" down from the top cluster weld. The spice weld is one half of fig 4-44 in AC43.13 since the original tube is the same as the insert tube. I'll attach a picture-
My last step is doing the paperwork. I was planning on simply filling out a 337 using AC43.13 as my data, but my IA says I need to do a field approval since its a larger tube and the spice doesn't match fig. 4-44 exactly.
Has anyone done a repair similar to this one who would share a 337 that I could use as data?
Could this repair be considered minor and get by with a logbook entry?
Any advice would be greatly appreciated.
Tom
ps 1941 BC-65 s/n 3116 N36196 with 2674 hrs TT. No landing gear replacements that I've found, although a repair on the LH main gear round tubing. Aircraft sat outside for better than 8 years before we rescued it in 08.

[Forrest Barber]

Re: FAA Issues SAIB for MLG Tie Struts

Hmmm. " I now have the landing gear repaired and need some help about how to approve it." Generally the A&P will submit the paperwork first for approval before doing the work. Did he think to do that?
let us see an overall photo of final tie strut . Do you mean that you fabricated the lower end of the tie strut? Bushing and all?

[barnstmr]

Re: FAA Issues SAIB for MLG Tie Struts

Heres your options:

1. Field Approval - Your cheapest option would be to submit your repair data to FAA-FSDO inspector and wait for him to do the approval. He or she may also want to do a conformity inspection. This way, the cost is free, except it could cost you a lot in down time while you wait. It all depends on your FAA. To initiate this method, have your IA contact his FAA interface inspector and send him your data.

2. DER Approval - Your quickest option would be to submit your repair data to a FAA-DER (structures) and wait for him to do the approval. I am guessing it might cost around $250 plus or minus $50.

Either way, you need to submit your data for approval. This would consist of a sketch or photos with a description (including materials) of the repair... basically like your posting, but give it a document number and date. Whoever does the approval will need a document # to approve.

I have access to one of the most reasonable structural DER's around. If you want, send me your document and I will see what he'll charge to do the approval for you.

[barnstmr]

Re: FAA Issues SAIB for MLG Tie Struts

OH... and about the fact that you are contacting the FAA or DER after the repair is already done....

This is not necessarily a bad thing, but in case the FAA or DER says it needs a different material or different dimensions, you could be facing a do-over.

[RobertP]

Re: FAA Issues SAIB for MLG Tie Struts

Hi All,

My Twenty pence ( sorry don't know what that is in bucks! ) worth but I think we have to be careful not to magnify this out of proportion with the FAA or we could easily be back to the lift strut debacle! I am all for flight safety and equally advance contact with the FAA if that helps an Administration Process but " To many cooks spoil the broth!" Just my view!