Hartzell aluminium prop tip repair

[yhuubert]

Looking for advice on repair of a Hartzell prop tip repair. One of my leading edge blade tips has a small nick. Can we repair it ourselves or does it need to go to authorized repair shop? What would constitute a FAA minor repair that my A&P/IA can do in this case?

I've read the Hartzell manual 115N and 202A, as well as FAA propeller maintenance AC, but still unsure on the minor repair limits for a corner tip. The FAA AC says: "An individual edge repair should not exceed a depth of 3/16-inch (4,7625 mm)" but I've not found where Hartzell says anything.

Hub: HC-C2YR-4AF
Blade: F7666A-2

Thanks for any advice!

 

[Doc Holliday]

Call a shop and get it correctly repaired.

 

[Clip4]

That’s significant damage and I would not fly the airplane. Your first step is to have an AP mechanic evaluate the damage and determine what needs to be done.

For what it’s worth, whatever caused that damage was visible to you on the surface during taxi and you fly a tailwheel aircraft that has a lot of prop clearance. I suspect the damage was from a wheel chock. Situational awareness.

 

[timrb]

Hypothetically, how would a shop repair damage like that? My first thought is weld on a bit of aluminum (TIG?) and reshape.

Tim

 

[Magman]

Tim
Most props are made from 2025 aluminum and are non- weldable.

Lycoming has a SB and AD ( US) that requires pulling the Accessory Case
in the event of a Prop Strike. Mandatory if prop must be removed for repair.
This plus dial the Crank would be a minimum action.

I suggest you get creative with pix and camera and contact a prop shop.
Airworthiness is not always determined by depth but by metal remaining after repair. A “Blade Drawing” is used is verify Minimum Chord at various
blade stations.

I have a C-152 that didn’t make it. It’s possible the may be able to
reprofile your tips.

 

[Brad Smith]

Propeller nicks are not owner allowed maintenance but falls under a repair that only an A&P/AI or the manufacturer can accomplish under 43.13. Depth of damage isn't a factor, must be repaired by certified mechanic.

 

[Ed Haywood]

That crack in the final photo is alarming. I would not fly without an A&P looking at it. Hartzell publishes repair standards.

TBH that does not look like debris damage, it looks like a prop strike from a wheel landing where the gear legs flexed too much. Is there similar erosion on the other blade?

 

[yhuubert]

Propeller nicks are not owner allowed maintenance but falls under a repair that only an A&P/AI or the manufacturer can accomplish under 43.13. Depth of damage isn't a factor, must be repaired by certified mechanic.

That for sure, done by my A&P/IA. Just not sure about the limits and minor vs major repair. As I understand from 8.73 b, shortening a blade is a major repair for sure. It does not say anything about tip corners though or where does leading edge transition to it. I've for sure seen some corner filing of leading edge being done as minor repairs. AC, 43.13, Hartzell docs all are kind of vague as for the exact limits.

 

[Bell206]

Can we repair it ourselves or does it need to go to authorized repair shop?

First, is your aircraft N-registered or is it Estonian registered? If its not N-reg, nothing here will directly apply to your situation. Second, have these blades been previously repaired? And do these blades have a life-limit? But for discussion I’ll answer your questions. Yes, your mechanic can repair it depending on the depth and width of damage. If the damage is within the minor repair limits, then yes, and your owner’s manual should give you the guidance for filing, etc. or reference another guidance document AC 43.13 -1B, Chap 8, Sect 4.

What would constitute a FAA minor repair that my A&P/IA can do in this case?

Your A&P would make that determination once he obtains the blade service limits. There should be a section in your owner’s manual where that is stated but generally it is in the Prop Component Maintenance or Overhaul manual. If you don’t have access to those manuals, perhaps contact Hartzell technical support for those limits. Regardless, the owner’s manual and overhaul manuals are written in a way to give leeway to your mechanic to determine what is a minor vs a major repair.

Can we just file it off - and in such case, must it be done the same amount on the other blade for balancing?

No, on filing the other blade. If you are removing that much metal, I doubt it is a minor repair.

Second question: can I continue flying in current state? Guess since it exceeds 0.79mm it must be repaired before

I would not recommend it. The prop is the most stressed component on the aircraft. And if you ever saw how much that prop physically bends in flight, you’ll fully understand why they state to repair any damage beyond .79mm. If in the end you must remove the prop for repair, perhaps inquire with the shop if they offer loaner props or have a good exchange program as an option to not lose your flying season?

 

[Ed Haywood]

No wheel landings or even bigger bounces. Always nicely on three points. The other blade tip is fine, just minor wear from years back.

I also wonder about the shape of the deformation. Very strange shape.

Hopefully Hartzell will also answer back with some guidance which docs exactly apply and what the limits are.

Have you checked the maintenance practices chapter of your Hartzell owners manual?

In the absence of separate guidance for tips, IMO the leading edge guidance would apply.

A CRS prop shop would know. They deal with this on a daily basis.

 

[Magman]

It seems to me the elephant in the hangar is being ignored.

The ENGINE is where the real cost & time kick in.

There is a very recent post; “ Prop Strike Inspection & reasonable

turnaround” that obviously addresses this topic. Time to re-read with

this scenario in mind?

OP has pix that can be used with Tech or shop to determine if they

should plan to arrive on scene to remove a prop or an engine.

Verdict?

 

[Dan Thomas]

Lycoming requires internal engine inspection if there is a sudden RPM drop. Picking up a stone won't do that.

 

[Lindberg]

It seems to me the elephant in the hangar is being ignored.

The ENGINE is where the real cost & time kick in.

There is a very recent post; “ Prop Strike Inspection & reasonable

turnaround” that obviously addresses this topic. Time to re-read with

this scenario in mind?

OP has pix that can be used with Tech or shop to determine if they

should plan to arrive on scene to remove a prop or an engine.

Verdict?

A prop strike in a taildragger is unlikely to be unnoticed.

 

[Magman]

Per AD Lycoming requires pulling the Accessory Case and addressing the

Crank Gear if the prop has to to be removed for a repair. Even if the

damage is caused by closing the hangar door. The Insurance folks just

loved that!

 

[Ed Haywood]

A prop strike in a taildragger is unlikely to be unnoticed.

Not necessarily. Plant a wheel landing a little too firmly on a grass strip and the tips can graze the surface such that you don't realize it until the next time you check the prop. Seen it.

 

[Ed Haywood]

Per AD Lycoming requires pulling the Accessory Case and addressing the

Crank Gear if the prop has to to be removed for a repair.

But not for inspection. So if the prop is pulled off but the prop shop says it does not need to be repaired, then no engine work is required. Got that from my engine shop.

 

[Clip4]

Couldn't have been any bigger object while taxing. Nothing near the hangar. But it's a grass runway and taxiways. My assumption is pebbles or stones when landing or taking off, or pulling something into the prop even when starting up or doing the runup checks.

I think I would walk your runway and runup area to see if these stones are present.

 

[Lindberg]

Not necessarily. Plant a wheel landing a little too firmly on a grass strip and the tips can graze the surface such that you don't realize it until the next time you check the prop. Seen it.

I said unlikely, not impossible. I think even in your scenario, there'd be indications. And I think that be a pretty soft field and a pretty firm landing.

 

[WDD]

In the US, an A&P can do minor prop repair, such as dressing up small nicks, but cannot do major work. The reason is that props are extremely critical and highly stressed during operation, and a specialized shop is needed. You have damage that doesn't look like a small nick that can be filed / dressed out.

Agree with previous comments 1) don't fly as it is, 2) get a proper propeller repair shop to fix or replace that blade.

 

[Ed Haywood]

And I think that be a pretty soft field and a pretty firm landing.

If you bounce a wheel landing and try to force it back down instead of going around or changing to a 3 point landing, it can easily happen. I have seen it numerous times.

 

[Skymac]

There would be absolutely zero concerned for the engine in my eyes. Absolutely believe it was just a rock or similar piece of debris, seen it many times before but this one just dinged the edge and my guess is the crack formed afterwards fairly fast from stress. That said without measuring it, it’s hard to say but I think it would definitely need to be profiled by a shop, my guess is the blade is trashed, I’d ferry it but that’s it.

 

[Magman]

But not for inspection. So if the prop is pulled off but the prop shop says it does not need to be repaired, then no engine work is required. Got that from my engine shop.

It seems the prop shop is saying; “ have it overhauled rather than repaired

and then you don’t have to do the AD”. A hangar door hitting a non-

operating engine and you have to do the AD. Maybe someone can explain

the concern? I’ve had that happen and one insurance company would

not cover in spite of the AD. Another occasion a very light strike and

the prop and mount were sent out, engine torn down with no problem

from a different company.

 

[yhuubert]

Talked to Hartzell factory senior technical representative and they said that damage is considered minor to to them, can be repaired per the 115N repair criteria.