The International Cessna^® 170 Association

Aryana wrote:

bagarre wrote:Should these be sent in as SDRs?

IMO, no.

To avoid the possibility of an AD or because an SDR is the wrong vehicle to convey the failure to the FAA?

Aryana wrote:IMO this isn't a serious failure, malfunction, or defect that constitutes notification to the FAA. Some of these tailwheels have thousands of hours on them, and they were never meant to last forever. What we do know is that they do have a very good track record over the past 60+ years.

Just like the main leaf spring, perhaps we should consider buying new tailwheels after say, 5000 hours/50 years...whichever comes first? Just a thought.

Yeah, what he said ! Mine has (had) approx 6000 hrs.

Correction guys.... The bolt that I thought broke at the grease hole did not break there. After further cleaning and inspection, it broke at the shoulder where it is machined down to fit the lower bearing.

Same place mine broke Ed.

Do you have an high res sectional shots of the break itself?

bagarre wrote:Do you have an high res sectional shots of the break itself?

No I don't. It really would not show anything as it evidently broke while taxiing. (About a two mile taxi) The two pieces rubbed together for quite a while and destroyed any evidence of a crack.

Anyone know whether the Alaskan Bushwheel bracket assembly with the kingpin bolt at issue here (p/n ABI 3216-00; Spruce p/n 06-00724) is a direct replacement for the Scott bracket assembly with the kingpin bolt (p/n 3216-00; Spruce p/n 06-01291)? I know that the entire Alaskan Bushwheel tailwheel assembly is a PMA direct replacement for the Scott tailwheel, but I don't know whether the individual parts are also PMA direct replacements for their Scott counterparts. From the similarity of the part numbers it would appear that they are. But I don't have any first hand knowledge/experience about it. The Alaskan Bushwheel bracket assembly is over $100 cheaper than the Scott one at Spruce.

I rebuilt mine with AB parts and everything fit

Excellent. Thanks Dave.

Ed, I think you said you had 6000 hours on your tailwheel when the bolt failed.

Bruce about how many hours did you have on your tailwheel when the bolt broke? If anyone else had the tailwheel bolt fail, about how many hours did you have on it when it failed? I have a little over 3000 hours on my airframe/tailwheel and I'm trying to get a rough idea of when to replace the bracket assembly with bolt (before it fails), leaving a reasonable margin of safety.

Thanks in advance.

The location of the failure (in these two instances) is very accessible with the tailwheel disassembled.
It's right on a shoulder which would indicate a stress riser is involved.

I really think there would be some indication of a failure by ways of a crack. (opinion)
Without being able to inspect the failure of a few bolts, we wont know if the crack forms over time and migrates until failure or if it shows no outward indication until the final moment.

What would be WONDERFUL is if a bunch of 170 owners at next annual cleaned and NDTd their bolt in search of cracks or other indications.
I have access to 3 tailwheels that I plan to dye check over the next year.

My unprofessional opinion is that this is similar to a landing gear failure where it would have been possible to detect the crack prior to the failure.

It would be impossible to know if the tail wheel kingpin that broke on my airplane was the original. But I believe by the style of data plate it could be. However my plane only have 5000 hours or so on it so that is all the assembly could possibly have.

https://www.backcountrypilot.org/me/my- ... bumid=4689


Saw this on Backcountrypilot.com

Aryana wrote:

bagarre wrote:

IMG_0007_.3.jpg

It's calling your name

Seafeye wrote:https://www.backcountrypilot.org/me/my- ... bumid=4689


Saw this on Backcountrypilot.com

Same tailwheel

I'm famous!

Look what Santa brought this morning...woohoo !

Wow a really cool card board box. To bad that somebody put that darn tailwheel on top and crushed it in a little. It's salvageable though I think. What you going to do with it Ed?