Failed Eddy Current Inspection

[Guitarmaster]

Cody told me you don't want to touch that stuff just for that very reason and that if you have a white airplane, you will be constantly washing red crap off of it.

[FloridaMan]

Make sure you let us know if a deal comes about on the top prop. My J-style spinner (LoPresti cowl) costs $2500 to replace if it fails and it makes sense to me to sell my good non-AD Hartzell and pay the difference if it happens.

Sent from my iPhone using Tapatalk

[ryoder]

I'm gonna consider it next 100 hours because I want a reseal anyway just for the inspection value and the fact that my overhaul is from 1985.

[Cody Stallings]

You could also consider going with a "B"Hub, with your blades an internals. No more AD. No red Dye.

My 2 pennies

[Yetti]

2) New B Hub = No AD. Cost = $6400.  don't think credits were included

What would a B Hub cost initially? Installation?

3) New top prop = No AD(at this point)(once someone prop strikes fixes the blades and keeps flying (or does some fancy aerobatics) then one cracks an AD can be issued). Cost = $9100

 

[piperpainter]

I think you're taking my prop!

[lamont337]

I think you're taking my prop!

 

I think you're right. At least I know it came from a good home. Going to ponder this for a moment as it will still require 100 hour ECI.

[piperpainter]

What did they tell you for a top prop?

[DaV8or]

Are the Top Props still no aluminum spinners?

[carl]

So I think I just learned this.

The eddy current inspection is a non destructive testing of metal using electrical current and measures the electrical eddies produced.

This is done on the prop hub to look for micro cracks.

If you fail the test you have micro cracks, and need a new hub.

 

I originally thought they were testing air flow eddies around the prop blades  and hub. 

 

But they really are not testing the blades at all. So the hub is the problem.

 

With enough time we will all fail the eddy test and need a new hub 

Or we can have a red oil mod , which will also, with time ,fail as cracks develop

 

Question; are the micro cracks with the eddy current test smaller then the cracks found when the red oil leaks. 

 

My guess is they are. so i would want to keep doing the eddy test instead of waiting for a larger leaks to develop

 

Did i get this right?

carl

[Andy95W]

I'm not at all convinced that you'll need a new hub. For 50 years these props were just fine on our Mooneys. Then some cracks started to appear in 300 HP applications, and agricultural airplanes, and acrobatic airplanes.

Next thing you know there's an AD for those applications.

Next thing you know there's an addition to that AD to include our relatively low powered Mooneys.

Yes, I believe some hubs will crack. All I really know is that an awful lot of us are getting the 100 hour inspections and very few are writing in to say they failed and need a new hub.

[Cody Stallings]

The B suffix hub is around $3300 last time I checked.

Top prop is around $8-8200.

O/H of your blades an internals + B Hub would be the way to go in my opinion.

The F7666A-2 blade is really hard to beat.

[carusoam]

Carl,

Another way or two to look at the situation...

(1) Eddy current testing is done once per year.

(2) The red oil will show anytime the crack is large enough to allow flow. Potentionally 364 days before the next eddy current test is done...

(3) Causes of cracks are one part torque (bolt and/or engine) and another part design/casting/machining quality. Casting/machining quality can be materials and process related...

(4) This is a long way to say that not all of the effected hubs are created with the crack potential, only some in some application. Enough to know that it can be a potential problem.

(5) Testing is an expensive hassle. It is a bit better than scrapping a good hub.

(6) Leaking red oil will be a hassle of a different color(?)

The real challenge is the economics.

The used plane is a bargain at the time of purchase.

Maintaining it is not much different than maintaining a new plane.

Buying a new prop is hugely expensive.

Experience:

My C got annual eddy current test that required traveling to get to/from.

A three bladed TopProp costs even more...

Sharing experience,

-a-

[carl]

yes.

i have the old hub and the eddy test too.

[Shadrach]

yes.

i have the old hub and the eddy test too.

I have a guy at KMRB. He will do it on the plane for ~$200 if I recall correctly.

East Coast Propellor may do an ECI for you at Lancaster.

Sensenich I believe will do an ECI at Smoketown.

That's 3 options under an hour's flying time. Most folks don't have it so good!

[Yetti]

I could see that a hub that is not designed to hold oil and has been known to sling grease past the seals could not perform as expected when filled with oil.    I have been trying to figure out what level the ECI tech has to be certified to.   The Eddy current test gear seems to be about $1000.00   

 

Does anyone have the volume 2 of the Hartzell service manual that they want to post?

[Shadrach]

My guess is that you are correct?

My understanding is the McCauley prop hubs use the red dyed oil .. No eddy current tests. Seems to work ok?

Sensenich here at KGVL modified our hub to hold the red dyed oil. $1000. No more AD. No 100 hour inspections. In less than five years will pay for itself in time and money flying to a prop shop for eddy current inspections. What's not to like

My guy charges me the same $150 he charged me when the AD came out. I think he charges new customers ~$200.

 

The Mooney flies 50-75hrs a year (somewhat less now that I also fly a Super Decathlon on occasion).  That's a 7-10 year schedule for me.  It's not a good investment for me.  Even at a modest rate of return the future value of that $1000 exceeds that of the cost of the ECI over the same period.   

[bonal]

The ECI is a PITA but it's just another inspection same as having to do the annual. For my normal hours I can go over a year between inspects and I have found a prop shop that does it for 125 just over an hours flight away. As long as it ain't broke I won't mess with it. I accept the situation as something that will help me from becoming an NTSB statistic. It's just part of the responsibility we have as aircraft owners.

[piperpainter]

Okay i just paid $6500 for a prop. However they gave me a credit for giving them an airworthy and re-usable blades prop. It does have the eddy current inspection. But why not just spend $6500 or $8500 (plus 190 install) for a new top prop. Your blades looked a little thinner than mine (they traced mine with paper and then put it on your blades).

[bonal]

All depends on your hours I can only manage about 60 to 70 so I can stretch it to a year and half. My prop shop is in San Luis Obispo so every so often I get to make a nice flight there. If God gives you lemons....

[HRM]

I had the ECI done three times.

 

Each time by a well-recommended prop shop.

 

Each time by a wrench who had been doing it since the inception of the AD. 

 

They told me that they had yet to find cracks in any of the hubs they scanned.

 

They told me that the AD was a colossal CYA by Hartzell after two planes collided in mid-air in the UK and they found mangled hubs in the wreckage (DUH!).

 

Two years, still no red dye.  

[jetdriven]

I love when facts trump dogma.

[flyntgr1]

If you want a B hub, there is prop with one for sale up on Barnstormers for under 3k. It has 72" blades, so won't work for us. But you can always get your prop shop to swap tour blades into it.

[Browncbr1]

I'm still learning... can someone please explain to me what the difference is for a Top Prop?  

I have a scimitar prop and I'm not sure what a top prop is.. the hartzell website doesn't seem to offer any detailed information... All I can see are the claimed benefits .. 

Is the Top Prop the same thing as the Scimitar prop?

[Cody Stallings]

Yes it is. Same props.