I just want to warn everyone of the practices that are going on in silent at Hartzell, aimed at forcing you to upgrade your hubs and props out of sheer greed.

Hartzell have been issuing frequent Service Bulletins and convinced FAA to issue AD's. They lobby hard that every SB shall become an AD with FAA, so as to force the matter even upon part 91 operators. More are to come. The MO is very simple - they start with the props and hubs that have the least support and base - and where it can be reasonably safe to assume the owners won't put up too much of a stink. Quite similar to the Cessna SID debacle. Bit like your garden variety school bully, really. Pick on the smallest you can find.

Many Hartzell props and hubs have recurring AD's. That's normal. But the newly issued SB's, forces the overhaul shops that do Hartzell props to comply with a bulletin preventing them from servicing hubs and props in a multiude of series. Now, a SB is not mandatory under part 91 (private use), but it is advisable and often mandatory for commercial use and will probably become an AD sooner rather than later. The SB is not based on any safety issues, as there have been no blade separations recorded, it's just a way to force new sales. Case in point:

My HC-83V20 hubs and props have a 250hr AD and a 500hr AD on them. In April Hartzell published a SB saying that the V and X hubs are no longer serviceable and need to be upgraded to MV hubs. At a cost of about $50-70K for a twin! This affects most Twin Bonanzas, most older Commanders, most Grumman Widgeons, most Navions, most Helio Couriers, most Pilatus P-3's, Saab Safirs, Queen Air's etc. This new hub has a shank removed, so would arguably be more susceptible to blade separation than the earlier ones with two shanks. Now, an SB, as mentioned, doesn't need to be complied with if you find a prop shop that isn't too affiliated with Hartzell - fully legal under FAA. The problem comes when one day it fails inspection. But the real problem comes elsewhere in the world - how are people going to comply in EASA land where everything from the manufacturer is treated as law and gospel? It's a bit like the Cessna SID's - a mild pain for many on the N reg, but an absolute aircraft-ending disaster in EASA land.

Don't feed the monster. There are alternatives out there who don't treat their customers like dumb walking cash machines. Use them if you can.

This has been going onfor years.

It's one of the main reasons I switched to MT props.

MTV

So is a MT Prop immune from this in the future? What kind of longeviety can be expected from MT Props? They are basically a wood core prop from what I understand, but their website claims they are "all weather". I'm having a hard time seeing how a wood prop will last longer than a metal prop.

Any thoughts

Same practice at Slick. Only they went after Bendix. Hartzell devours it's young, Slick devours your young.

EB

Lawleraero wrote:So is a MT Prop immune from this in the future? What kind of longeviety can be expected from MT Props? They are basically a wood core prop from what I understand, but their website claims they are "all weather". I'm having a hard time seeing how a wood prop will last longer than a metal prop.

Any thoughts

They hold up just fine. The vast majority of damage to a propeller occurs to the leading edge. The metal props incur such damage, from stones, rain, snow, etc. and at inspection time your mechanic treats that damage by filing off some of that precious metal leading edge.

The MT props have a stainless steel leading edge. That edge may incur a little damage, but it's a LOT harder than aluminum, so it will go a long time and you never have to dress out nicks. When it gets REALLY ugly you have a new leading edge bonded onto your prop and it's like new.

With a metal prop, every time it's dressed, it gets smaller, less performance, and eventually, new blades.

Damage to the face or back of an MT prop is easily fixed with some epoxy to seal it.

Worst case scenario, you stuff your pride and joys nose in the dirt,that MT is MUCH less likely to damage your very expensive engine internals.

MTV

Sorry for your pain Adam. Hartzell has been at this game for a while and the GA community is taking note. I would explore any option available to not put one nickel in their pocket, when the time comes.

Dear Backcountry Pilot Members:

After coming upon this post by Stratobee recently, I was concerned about the level of inaccuracy with respect to the history of this issue and Hartzell’s response to it, including our support philosophy. As the Executive Vice President of Hartzell Propeller, I appreciate the opportunity to respond.

For context, Hartzell introduced model HC-83X20-2 propellers in 1954, later modified to model HC-83V20-2 – the subject of Stratobee’s posting. These propeller types utilized a “double-shoulder” blade retention system and a solid bearing/split retainer design. Over the years, Hartzell developed several variants of the “double-shoulder” design and this “double-shoulder” style of propeller was provided on an OEM basis for a variety of aircraft models. Although Hartzell stopped shipping the HC-83X20-2 propeller on an OEM basis in 1966, we continued to provide service, support and select parts for over 55 years.

In 1997, with many of these “double-shoulder” propellers having been in service for over 40 years, a variety of field reports indicated that, after multiple decades of use, blade cracking could occur on double-shoulder blades. Since 1995, there had been a growing number of cracked parts, including reports of 37 cracked blades, 4 cracked clamps, and 5 total blade separations from hub fatigue cracks, all on this “double-shoulder” style propeller. These cracks were discovered on several blade models, indicating that the issue was not aircraft specific. Our evaluation determined that a variety of factors could induce cracks, including corrosion, uneven shoulder wear, and inconsistent rework of the blade shank during overhaul. Given the potential severity of an in-flight blade separation, we took action and issued Hartzell Service Bulletin 217. The FAA followed up shortly thereafter with Airworthiness Directive 97-18-02 in August 1997. This A.D. required an initial dye penetrant inspection, then repetitive disassembly and inspection of hubs every 250 hours, and blades/clamps every 500 hours. The propeller inspections done pursuant to SB 217 and AD 97-18-02 resulted in the discovery of additional cracked components. There is no doubt the Hartzell SB and FAA AD were necessary and that they clearly targeted a flight-safety issue.

Here is a link to an article from the May/June 1997 issue of the Navioneer which readers might find useful as they form their own opinion: http://www.hartzellprop.com/notes/AboutSB217.pdf.

In March 1998, Hartzell Service Bulletin 232 was released, introducing the “MV” propeller. “MV” propellers are a single-shoulder blade design which by its nature eliminates the double-shoulder system. The single-shoulder configuration eliminated the possibility of uneven load sharing between double-shoulders, and subsequent potential double-shoulder blade cracking. In addition to introducing the “MV” propeller, in April 1998, Hartzell released Service Bulletin 233 which both permitted - and provided instructions for - conversion of older double-shoulder propellers into the “MV” type, accomplished through blade modification and replacement of certain parts which changed the configuration to a single shoulder style. With this improved design and upgrade path available, owners of affected propellers would now have the option to opt out of the repetitive inspections by pursuing the “MV” conversion.

In order to both encourage owners to comply with the Service Bulletin and AD and to consider the “MV” upgrade path to an improved design, we undertook a variety of activities, including restarting production of components that had not been manufactured since the 1960’s, offering, at 50% off regular list price, various parts as well as complete “MV” propellers and applicable “Top Prop” STC replacement propellers, both of which provided a path to remove the requirement for repetitive inspections. This half-price parts/propeller program began with the issuance of Service Bulletin 217 in August 1997, and continued for approximately 2 ½ years until December 31, 1999, a date well past the AD compliance deadline of September 30, 1999.

While some Hartzell customers took advantage of the 50% off offer to upgrade their propellers to the “MV” configuration or a “Top Prop” option, others did not, instead purchasing only the parts needed to pass the inspection of their older double-shoulder designs. These propellers were still subject to repetitive inspections under AD 97-18-02.

Over the last 13 years of repetitive inspections, Hartzell has received additional reports of cracked components used in the 1 and 8 style components. So, after supporting these 1 and 8 style hub propellers for over 50 years, we made a decision to stop our support and drive migration to improved design options. On March 14, 2012, Hartzell released Service Bulletin 331, alerting owners that we would stop making parts or maintaining technical publications, such as overhaul manuals, for these 1950’s vintage 1 and 8 style designs. We understood that this action would require owners of these 1 and 8 hub style propellers to ultimately upgrade to an improved design. However, we believe that requiring the upgrade to these improved designs is merited.

This summary brings me back to Stratobee’s original post. He likens our company to the devil, a bully whose actions are driven by greed, not safety, “because there have been no blade separations recorded.” He also asserts that we have been doing all this silently (though he cites the Service Bulletins that we publish that publicly outline what we are doing and why). On all fronts, we vigorously disagree. We provided ongoing parts and technical support for over 5 decades. In the face of data identifying a safety issue, we developed multiple paths for owners to take to enhance flight safety. With no requirement to do so, we went back into production on a variety of components and propellers and offered them at special pricing for two and a half years, extending the pricing beyond the SB/AD compliance period. We think our actions have been thoughtful, prudent and fully consistent with our motto: Built on Honor.

Sincerely,

Jim Brown III
Executive Vice President
Hartzell Propeller Inc.
PH: 937-778-4267
E-mail: [email protected]

With that kind of honor, y'all need to start making me some Rotax blades!

While you're on the horn, can you confirm something? It is Ohio lore that a guy named Chafin hand carves your propellers from a solid block of metal. He can do it in total darkness by feel. He beat Beelzebub himself in a 24 hour Etch-a-Sketch competition back in the 70's and also flies some plane made of irrigation pipe he calls an S7.

Fact or fiction?

I have a question too. Is it true that those double shoulder Hartzell propeller parts that you reference crack the same whether they are sitting on the shelf or in service?

I've always been puzzled as to why at least one AD on the Mooney M20C propeller was not hour but year activated. I also wonder if the new series of props are hour or year rated for overhaul. I really don't know. I'm just asking.

EB

Beelzeprop?

Mr. Jim Brown III 's response notwithstanding, it appears Hartzell may have a PR problem on their hands as I've heard similar complaints from other sources over a number of years. Note that I have no experience with Hartzell myself, as none of my aircraft have Harzell propellers (McCauley, MT, and Schleicher) - - Oh wait, I do have an old wood Hartzell fixed pitch prop hanging on the wall in my living room. Made in the early 40's from what I can tell and still looks airworthy - - I had it on my previously owned Aeronca 7AC for a time and it worked just fine. 70 years old, I'd say it was "built on honor".

MTV outlined some of the MT prop's wear characteristics. Also consider that MT's composite over wood construction is significantly lighter than a typical metal prop, this results in much lower centrifugal stress to hub and blade shank as well as lower gyroscopic loads while manuevering. The wood blade core also helps absorb engine power pulses and this results in a smoother feeling prop. Wood has no fatigue life limit.

Disclaimer: Not associated with any prop mfg. just a happy MT customer.

bumper

It is really hard to analyze SB & AD's from a sample of a few cases. Being in the "biz" myself, I have had to pay for quite a few service bulletins. I do also own a fairly large repair station and see hundreds of aircraft annually for repairs and checks. We do find a large number of the service bulletins justified. There are loads of prop bulletins against nearly every manufacturer and when you actually condemn a prop, before it goes to overhaul, it does get your attention., like red dye leaking out of cracks in Skymaster props. I especially love it when the customer blames you for finding it.

I have had items fail on me, and I ask, "why isn't there a bulletin on these?" Hard to answer, occasionally it comes down to political influence. I am embroiled in a larger lawsuit against a turbine blade manufacture and the overhaul facility. Had a blade separate on landing and caused a major fire on the aircraft (5 hours out of overhaul!). Yet with 25 failures on the same part number blade, including 8 fatalities, there is no bulletin.

So if your aircraft looked like this, would you prefer to have a bulletin, or continue to take your chances? You can look up the pics yourself, and the accident,it is in the database, N208JW. I'm sorry when people feel the economic hardship of aircraft ownership. I also have had the hard reality slammed home to me. In the military I wasted, could say crashed, 3 aircraft. One burned al the way to a sliding down the runway shedding parts end. Just last week I had to glide to land due to a fresh governor failure. I thank all the deities out there I was still within gliding distance of the field. Some of us had had a truckload of failures and don't say the manufacturer is trying to feed off us, and some manufacturers seem to get a pass, so they can continue to push junk:

Many of the ADs out there are well justified, no doubt, as dog pilot says.

My point is this...why not build a better product from the git-go, or learn from your mistakes? Hartzell's mistakes caught me twice on compact hubs. I won't buy another Hartzell, not necessarily because of the ADs, but because I don't trust the quality of their products.

Personal opinion, and we all know what those are worth.

MTV

Dear Hartzell company response,
I can appreciate the fact that you have made efforts to offer reduced price upgrades for older prop hub designs. What I have a problem with is the service bulletin being issued and/or any promotion of it becoming an AD. If a part is out of limits, or cracking lets replace it on a case by case basis.. the VERY frequent inspections already imposed are bad enough without forcing us to comply with an AD so that you can sell updated models. Its legal action against your customers that leaves a bad taste in our mouths. We are regulated enough..
My Suggestion:
Design and sell a product that is such a big improvement on your former product that the consumer is enticed to buy it vountarily. It would seem from the reponses here that your compettitor is headed in that direction.