K forced landing GA with injuries 5/20/21

[mike_elliott]

Thanks, Anik and I have communicated. The Mooney Summit, Inc will be reaching out to Leon and Sharon. I know this injury well.

[aviatoreb]

4 hours ago, Anik said:

Aloha All!  I’m Anik, the pilot Leon Huffman’s daughter, and Sports Medicine Physician.  

Aloha Anik- thank you for the update and I am very grateful your family is recovering.  All the best and I will definitely reach out.

[RobertGary1]

On 5/22/2021 at 7:13 PM, A64Pilot said:

The thing that struck me about that photo was the rod was completely separated from the crankshaft, and I’ve not seen that before, usually a rod will break in the middle somewhere.

Makes me wonder if a rod bolt broke. 

When my IO-360 failed the rod separated from the crank.

-Robert

[1980Mooney]

Final is out.  Mechanic/Maintainer failure.  Cotter pin missing on #4 connecting rod.  Nut came off - was found in crankcase oil pan.  @A64Pilot is correct that it broke in the middle  -see Docket..Engine had been overhauled 28 years before the accident.  

Edited July 22, 2023 by 1980Mooney

[hubcap]

I wonder how many revolutions that engine had turned before it came out?

[MikeOH]

2 hours ago, hubcap said:

I wonder how many revolutions that engine had turned before it came out?

1240 hours SMOH X 60 min/hour X 2500 rpm = 186 million 

[hubcap]

2 hours ago, MikeOH said:

1240 hours SMOH X 60 min/hour X 2500 rpm = 186 million 

I know…right? I did the math and it’s a significant number.

[hais]

On 7/22/2023 at 2:49 PM, MikeOH said:

1240 hours SMOH X 60 min/hour X 2500 rpm = 186 million 

Those are too many hours to count as infant morality...would the issue be detectable via oil analysis? 

[A64Pilot]

I ascribe to the likelyhood that the pin came out myself or even possibly broke and came out from being re-used, but the report seemed to postulate it was never installed. I assume because the remains weren’t found? I’d like to think it wasn’t missed.

In fact it’s not common for rod bolt nuts to be cotter pinned, and yet it’s extraordinarily uncommon for a nut to fall off, just like the cylinder stud nuts don’t have cotter pins.

Engines have always had me wondering, pretty much all the bolts are course thread while everything thing else on an aircraft is fine thread, because fine thread is better?, and only odd ball things have safeties but things like spark plugs, ignition harnesses, the intake and exhaust, magneto’s etc don’t?

I believe it’s only the smaller and older Continentals that have cotter pins on rod bolts and the newer and bigger motors don’t? Do any Lycomings have cotter pins?

I believe thread pitch difference may be why and I’m not abdicating leaving cotter pins out, just it’s interesting is all.

[Pinecone]

Isn't there a service bulletin about installing the rod end cotter pins, that if they are not installed properly, they hit something inside the engine and are broken?

[Fly Boomer]

4 hours ago, M20Doc said:

Cotter pin remains might have been found in the oil suction screen, but many don’t clean them or know they exist.  Sadly the one in your 550 isn’t accessible during normal maintenance.

Also I think not on the TSIO-360 in the K.

[A64Pilot]

Are the rod bolts in a 550 cotter pinned?

[A64Pilot]

On 7/24/2023 at 4:02 AM, hais said:

.would the issue be detectable via oil analysis? 

Very unlikely, in other words in my opinion, no.

This kind of thing is what chip detectors were made for.

However I don’t think your 550 has cotter pins in the rod bolts

Edited July 30, 2023 by A64Pilot