FlyTester

Hartzell Prop Hub AD - NEW Alternate Means of Compliance!

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I'm the proud, new owner of 1963 M20C, N6578U since yesterday. The prop is of the older Hartzell "non-suffix" hub with the 100 hr recurring AD for an eddy current inspection.

During the pre-purchase survey earlier this week at Advanced Aircraft Services, I had expressed interest in having the prop overhauled if I bought the airplane.

AAS' neighbors at Western Aircraft Propeller alerted me to a recent Aug 27, 2012 update to Hartzell service bulletin HC-SB-61-269 "Propeller - Hub Inspection."

The update is significant in that it adds an FAA-approved alternate means of compliance that effectively eliminates the eddy current inspection requirement WITHOUT a costly upgrade to the B-hub.

The service bulletin is updated to include an Optional Terminating Action for the hub inspection by "modification of the propeller hub to the oil-filled configuration in accordance with Hartzell Service Letter HC-SL-61-273."

According to SL 273, "Converting the propeller to an oil-filled configuration will provide a method for early detection of a possible crack in the hub. The hub cavity will be filled with oil that contains a red dye. If a crack in the hub occurs, the red dyed oil will provide a visual indication"

At ~$3300, the cost of an overhaul and incorporation of SL 273 kit falls about halfway between that of a prop over haul and that of a normal prop overhaul with upgrade to the B-hub.

Work on my airplane's prop overhaul and SL 273 incorporation commences next week.

Page from HC-SL-61-273.pdf

HC-SB-61-269.pdf

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Finally some good news for owners with the AD still in effect. Hadn't seen that new SB come out.

If your saying replacing to the correct hub to a "B" hub is going to run almost 7 amu's now, then that sounds like Hartzell is pricing that option out of the market. The Top Prop conversion (which I did this spring) is only another 1.5 amu's installed and provides a boost in performance. At least it did for me.

Brian

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Great for the guys who still have the old hub. I had commented against the AD after it was issued and had called Hartzell. As I recall, the AD was prompted by failure of one under maintained prop and FAA issued it as an emergency AD without the standard comment period. Talk about knee jerk reaction. There were numerous suggestions for alternate compliance. My old hub had only about 500 hours since new and as far as I know, went in the recylce bin. Sure wish I kept it. I didn't have a capable prop shop close enough so didn't want to fly every year (original compliance) at annual to a remote site.

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If your saying replacing to the correct hub to a "B" hub is going to run almost 7 amu's now, then that sounds like Hartzell is pricing that option out of the market.

No, that's not quite what I meant.

Based on quotes from several sources:

1. Normal OH ~$2000 (retains AD)

2. OH with new SL 273 incorporation: ~$3300

3. OH with B hub added: ~$4500

4. Top Prop ~$8500

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I'm cheap. At $200/inspection/year, I can go a long ways without this modification. Thanks.

I'd like to say economical and I'm that way too but if you are flying more than 100 hours a year don't you need to do the inspection more often? What about the logistics of getting the inspection done? Maybe you have a shop on the field that can handle it maybe not.

Of course my former plane had a new hub so I did not have to worry.

To me the annual inspection is more of a hassle than the cost unless you find something. Removing the hassle of needing to do something every year or 100 hours to me the $ become worth it a some point.

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Ok, I fly right at 100 hours per year and it costs me $200/yr. I fly from VT to CT (1 hour flight each way) to get it inspected. I help by taking off the spinner and reinstalling it. I like to fly so this is another excuse to go flying.

And I'm still CHEAP!

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Cheap gets expensive when the buyer of your airplane offers 7K less becaue they are going to make you pay for a new prop. You might as well enjoy the free 3 knots and easier to sell.

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Hi Brian, are you aware of the >24" at 2350-2550 rpm avoidance area for the Top-Prop.

greetings, Alex.

Kind of hard to miss the placard and markings on the tach. Not sure what your point is?

I don't get anywhere near 24" MP at the altitudes I normally fly cross country at, so it's a non factor. If I'm down low, I run at 25/2600 or pull it back for some low and slow sightseeing...again, no impact.

Cheers,

Brian

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I'm cheap. At $200/inspection/year, I can go a long ways without this modification. Thanks.

That is what I was doing up until an overhaul was required, so I bit the bullet and upgraded. I was saving in the mean time, so it came out of the MX funds... Nothing wrong with doing it that way.

Brian

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I picked up the airplane today. I also got to witness the hub being sealed with the dyed oil instead of grease. According to Hartzell, I have the very first Mooney with the new AD-eliminating service bulletin incorporated. The fix has been installed in a dozen or so Trinidads with fine results.

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Ite good this is available, since it will help others when thinking about the difference between long-term cheap and short-term cheap. I'm not much of a fan of spending money, but I went with the B hub when I needed an overhaul. The eddy current inspections were not available at my home field, and the closest capable shop charges ~$300. The new hub added $1700 to the prop overhaul I was in for. I figured six years and I'm money ahead and I'd save some hassle along the way. That was a bit over six years ago. If this new method adds only $1300 to the overhaul cost, it's worth considering if you need any prop work done.

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I spoke to Randy at East Coast propellor , He said the fix is not a great repair , He said that Macauley did this years ago and still have trouble keeping oil in the hubs .... As a former Macauley owner in my Beech , I did replace a prop for leaking red dye , The ECI inspections are cheap in the grand scheme of things, and I am doing the ECI inspections in my Mooney.... Also My mooney has less than 100 hours on the prop overhaul , So I will not redo the hub.... If someone trys to knock 7 k off for a B hub , They are not a real buyer , They are a tire kicker...

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The ECI inspection is not required for a "B" hub correct? I dont see any buyers subtracting for a "B" hub hartzell, but an AD hub is going to cost the seller.

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OK, so buyers will either have to deal with a pesky $200-500 AD due every 100 hours, or do the hub dye mod, which could turn into a prop overhaul for $3300-$7000. Or a B-hub conversion which is 7K, or a new BA prop for 8K. None of these are appealing to buyers, and they are going to adjust the cost of a seller's airplane for this. 7K deduction iis about right for a non-B hub, non-SB prop. Thats the market.

In our case, doing a 201 windshield or a panel freshen up (3K), and a Hartzell B-hub overhaul was right at ten grand, which was the cost difference between a M20F and a J. We skipped the F and bought a J.

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OK, so buyers will either have to deal with a pesky $200-500 AD due every 100 hours, or do the hub dye mod, which could turn into a prop overhaul for $3300-$7000. Or a B-hub conversion which is 7K, or a new BA prop for 8K. None of these are appealing to buyers, and they are going to adjust the cost of a seller's airplane for this. 7K deduction iis about right for a non-B hub, non-SB prop. Thats the market.

In our case, doing a 201 windshield or a panel freshen up (3K), and a Hartzell B-hub overhaul was right at ten grand, which was the cost difference between a M20F and a J. We skipped the F and bought a J.

I thought a B-hub add-on at overhaul time would bring the total cost to $4500. That's a lot less than 7K. Reference post #4. Somebody's got plain wrong numbers because 7-10K vs 4-5K is a big disparity in quotes.

Running a non-B hub until it needs replacement and then coughing up and additional 3AMUs at overhaul seems like a heck of a lot better deal, not discussing the non-economic personal valuations of time and feelings on taking the aircraft to the shop at 100hrs et al.

BTW, is anybody out there who has had a non-B hub actually fail the eddy current inspection? I know the non-suffix hub is not unique to Mooneys (Pipers got them too) and from my cursory read on this matter, it seems like the usual Airworthiness Directive Standard of "one failed among 9000 operating units, compliance is mandatory", which we call in the military: STANDARD, SNAFU. But I don't have the numbers. It doesn't sound like these things were failing en masse....

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I thought a B-hub add-on at overhaul time would bring the total cost to $4500. That's a lot less than 7K. Reference post #4. Somebody's got plain wrong numbers because 7-10K vs 4-5K is a big disparity in quotes.

Running a non-B hub until it needs replacement and then coughing up and additional 3AMUs at overhaul seems like a heck of a lot better deal, not discussing the non-economic personal valuations of time and feelings on taking the aircraft to the shop at 100hrs et al.

BTW, is anybody out there who has had a non-B hub actually fail the eddy current inspection? I know the non-suffix hub is not unique to Mooneys (Pipers got them too) and from my cursory read on this matter, it seems like the usual Airworthiness Directive Standard of "one failed among 9000 operating units, compliance is mandatory", which we call in the military: STANDARD, SNAFU. But I don't have the numbers. It doesn't sound like these things were failing en masse....

Fly Tester's quote for a B-hub upgrade on a hartzell prop for him was $4,500. Plus the cost R&R. plus the risk of the 500$/each blade clamps being condemned. Also consider the fact that if one blade does not pass thats an additional 2 grand right there. Then they convince you to buy a blade set for 3K because one is at limits and one is new, so you end up with a significant risk of a 7K hartzell prop when the dust settles. Many prop shops never met a prop that didn't need an OH.

From a buyer's perspective, any pre-J we looked at with a "non-B hub hartzell" was an automatic 7K deduction from "book" value. Not necessarily from asking price. But it was a pretty immediate cost incurred if buying that particular airplane, and it is something to consider as a seller if ypu own one of these planes. Byuers dont want a plane that has a 5$ an hour cost surcharge due every 100 hours. I think a hub-dye non-B hub prop fresh out of a shop would also be a "no deduction" same as a fresh "B-hub" prop, or a fresh -BA prop.

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BTW, is anybody out there who has had a non-B hub actually fail the eddy current inspection? I know the non-suffix hub is not unique to Mooneys (Pipers got them too) and from my cursory read on this matter, it seems like the usual Airworthiness Directive Standard of "one failed among 9000 operating units, compliance is mandatory", which we call in the military: STANDARD, SNAFU. But I don't have the numbers. It doesn't sound like these things were failing en masse....

Western Aircraft Propeller Svc (where I did my OH) claimed that in their several decades of business they had seen only 1 hartzell prop fail an eddy current inspection. That particular prop was on an aerobatic airplane performing almost daily on the airshow circuit. If I read it correctly, I think the Hub Dye SB fix is not applicable to installations on aerobatic airplanes.

...Also consider the fact that if one blade does not pass thats an additional 2 grand right there. Then they convince you to buy a blade set for 3K because one is at limits and one is new, so you end up with a significant risk of a 7K hartzell prop when the dust settles. Many prop shops never met a prop that didn't need an OH

I knew when I bought the airplane that the prop needed an overhaul and planned accordingly. On my budget I'm not sure if would have upgraded to the B-Hub. For just a few hundred dollars over the price of the nominal overhaul, I got rid of the AD. At the cost of EC inspections, the mod pays for itself in 3-4 years. Sure enough my blades measured too short. I lucked out though because the shop had a servicable pair in stock from another customer's prop upgrade. I traded my blades plus a little cash for the replacements. Total bill (including blade trade) came to $3600.

For roughly $40K, I now have an M20C with 92 SMOH (Penn Yan), a PowerFlow exhaust and a newly overhauled prop and get to test fly my own bird for a change. Not bad for a first airplane purchase. I'm tickled PINK!

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McCauley oil filled there threaded an a few models of the threadless propellers......These propellers were not designed to hold oil.... Everyone will leak at some point, the Hartzell will be the same way.... When sealing a prop, it's being done static on a table or upright.... Then you bolt it on a engine flange, spin it 2700 rpms....... The blades that weight around 13lbs each, are now up around 20 tons on the primary thrust bearing. The hub under those conditions flex... That's just the way it is with the cast-aluminum hub...

With the flexing, the oil will find its way out.....

We do the eddy current test at our shop, an have yet to find a hub srap with a internal crack. But on the other hand, the so called B hub is a much more robust assembly on the inside than the A suffix hub.

B hub is the way I would go, rather than the oil fill conversion. My 2 cents

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Welcome aboard Cody.

You have brought an interesting point to the annual hub challenge.

Best regards,

-a-

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Just to add fuel to the fire , Prop hub eci inspections are not a new thing , there are many planes requiring this , When I had mine done east coast coordinated with other shops in the area , and came out and did mine on the plane ... Boom 180 dollars and its done.......So the inconvienence factor is negated...

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Having to do an eddy-current inspection every 100 hours is a pretty major inconvenience. We would have had to do it three times last year. That's 400-500$ a year right there, plus the aircraft time to ferry it to the shop for the inspection (40$ a trip).

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