KOXR Mooney blade failure

[ragedracer1977]

I bet was exciting.  All I know is pilot reported engine failure and landed safely.

 

 

[Bartman]

Wow !

We always check the prop for nicks that can propagate, but I don't see anything on the closeup.  

[ragedracer1977]

I realized that’s an L.  Porsche Mooney. Wonder if it’s converted to an io-550

[bluehighwayflyer]

Yes.  If it is an L it has definitely been converted.  The original L cowling looked totally different.

”Props” to the pilot.  Well done, Sir.  
 

 

[aviatoreb]

WOW - scary!

[MikeOH]

Isn’t that the new 2 1/2 blade STC for those that can’t decide between 2 and 3 blades?

I understand they’re not quite as smooth, however

[201er]

I thought 2 blade is supposed to be faster

[Hank]

11 minutes ago, 201er said:

I thought 2 blade is supposed to be faster

My C has a 3-blade Hartzell, and I seem to cruise between book and book+5 mph. 

The extra blade helps with climb, and makes a good airbrake when I come into the pattern too fast, just push it full forward--i can hear and feel it working.

[Coachella Bravo]

Its a new prototype, 3 blade for takeoff and climb, 2 blades for HS cruise.

;-)

[Schllc]

I can’t even imagine the vibration/oscillation that engine was going through. I always wondered what would happen if you lost a blade in cruise. 
it probably wasn’t as bad with the heavy half staying on the plane. 
im dying to know if he shut down the engine to land. I’ve always thought you would have to…

[WilliamR]

So very lucky from what I assume was very quick action to shut the engine down. I was acquainted with two pilots in separate similar incidents that perished. Both on takeoff. One was a partial blade separation and the other was a full blade separation. Neither plane traveled more than 0.5 miles before crashing. First was fatigue on a fixed pitch prop. The second was improper prop maintenance on a constant speed. 

William

[201er]

Interesting that there doesn't appear to be any damage to the airframe. Where did the blade go? Lucky that it didn't go through the windshield!

[Schllc]

2 hours ago, 201er said:

Interesting that there doesn't appear to be any damage to the airframe. Where did the blade go? Lucky that it didn't go through the windshield!

I’m pretty sure that centrifugal force would preclude it from coming even close to the airplane.  I would think vibration damage could be bad enough to rip the engine from the plane. 

[Bartman]

On 3/8/2025 at 2:09 PM, Schllc said:

I can’t even imagine the vibration/oscillation that engine was going through. I always wondered what would happen if you lost a blade in cruise. 
it probably wasn’t as bad with the heavy half staying on the plane. 
im dying to know if he shut down the engine to land. I’ve always thought you would have to…

Look at the misalignment between the cowl and the spinner.  I would think the engine mount and Lord shock mounts took a beating in the few seconds she was at full RPM.  That is one lucky pilot.

[exM20K]

On another forum, a pilot friend of the mishap pilot reported that (paraphrasing): the mishap pilot thought he lost a cylinder at 3500’, was astonished at the vibration, and immediately shut it down.  He dead sticked it to that landing. Well done.

Along that route, it looks like the prop picked the best available time and place to depart. I’m not a socal flyer, but from ForeFlight, the coast looks pretty inhospitable for a forced landing.

-dan

[Schllc]

That blade looks like a casting in that picture. I always thought they were machined out of billet for this reason. 
it is possible the billet had a defect but it’s a whole lot rarer than it is with cast aluminum. 
defects from porosity in casting is very easy, and once that corrosion starts its inexorable. 
wonder if McCauley is going to replace it so they can analyze. 

[DXB]

I imagine this requires crank  inspection like a prop strike?  The asymmetric loads must be enormous 

[MikeOH]

7 hours ago, DXB said:

I imagine this requires crank  inspection like a prop strike?  The asymmetric loads must be enormous 

I'm typically not one for 'overkill' solutions, but I'd NEVER trust that engine again, even after a complete overhaul. I can't imagine the over stress placed on EVERYTHING, engine cases included.

[MikeOH]

15 hours ago, Schllc said:

That blade looks like a casting in that picture. I always thought they were machined out of billet for this reason. 
it is possible the billet had a defect but it’s a whole lot rarer than it is with cast aluminum. 
defects from porosity in casting is very easy, and once that corrosion starts its inexorable. 
wonder if McCauley is going to replace it so they can analyze. 

How is an aluminum billet made?  Doesn't it have to be 'cast' as well?

Also, isn't that 'rough' appearance typical of any metallic fracture type failure? I.e., I wouldn't expect a 'smooth' surface.

[Marc_B]

16 minutes ago, MikeOH said:

I'm typically not one for 'overkill' solutions, but I'd NEVER trust that engine again, even after a complete overhaul. I can't imagine the over stress placed on EVERYTHING, engine cases included.

Makes me wonder...what happens to engines with catastrophic failures or that were involved in incidents such as this?  Does this get returned as a "core" with a purchase of a new/reman engine and go back into the pool of parts?  I'm not sure I completely understand the testing process for reman engine parts to begin with...

[MikeOH]

1 minute ago, Marc_B said:

Makes me wonder...what happens to engines with catastrophic failures or that were involved in incidents such as this?  Does this get returned as a "core" with a purchase of a new/reman engine and go back into the pool of parts?  I'm not sure I completely understand the testing process for reman engine parts to begin with...

Yeah, the 'pedigree' of the parts has been something that's bothered me with a 'factory' overhaul.  Honestly, I'd rather have my engine overhauled by a good shop and get as many of my parts back!  At least I know their history.

[PT20J]

[NickG]

Looks like a composite blade and not a single piece of forged aluminum.

[Hank]

7 minutes ago, NickG said:

Looks like a composite blade and not a single piece of forged aluminum.

Looks to me like an internal flaws in lone with the McCauley logo, you can see the darker color and smooth curved area. The darker part at the right edge is a typical break at 45°, from overstress.

[EricJ]

20 hours ago, MikeOH said:

I'm typically not one for 'overkill' solutions, but I'd NEVER trust that engine again, even after a complete overhaul. I can't imagine the over stress placed on EVERYTHING, engine cases included.

I had an injector clog at full throttle just after takeoff and I thought the engine was going to come off the airplane it shook so hard.  Four-cylinder motors aren't happy when a cylinder stops making power but still has full compression.  I had to keep it at full throttle to maintain about 100 fpm climb to get around the pattern and land, so it did that for a lot more than a few seconds.   I've put over 900 hours on it since then.