Backcountry Pilot • Broken crank on climb out

Broken crank on climb out

Lycoming, Continental, Hartzell, McCauley, or any broad spectrum drive system component used on multiple type.
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Broken crank on climb out

Had an interesting flight a couple of weeks ago, coming back from Arkansas - dropped into Newton City to clean a fouled plug, looked the engine over, did a good run up and took off. On departure got to about 900’ agl when I caught a faint odor of something burning… a few seconds later more smoke outside and then oil coming in through my heater vent near the rudder pedals. Bad noises commenced but the prop was still turning so eased around and slipped back to the runway. On roll out the prop stopped with a thump. No prop strike or any drama with the landing - just rolled out and pushed it off the runway. Additionally, noticed the oil filter adapter was sitting about 2” off the accessory case… wasn’t that way when we buttoned her up after swapping the plug.
Foreflight track shows 3 minutes, 28 seconds from takeoff to landing…

O320-A2B with about 500 hours smoh. Flown just over 150 hours since April.
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LuscombeRob offline
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Re: Broken crank on climb out

Good job getting down. I had similar extensive damage when the GO-300 in my 175 had a piston rod come loose at the piston and beat the engine to broken pieces like yours. The bad thing is that my insurance was for airplane damage and not engine damage. Like you I had no airplane damage. Landed on the highway near Santa Domingo Pueblo on the Rio Grande.
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Re: Broken crank on climb out

Wow, did the bolts on the adapter break or did they fall right out?
Good job on getting it down safely.
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Re: Broken crank on climb out

contactflying wrote:Good job getting down. I had similar extensive damage when the GO-300 in my 175 had a piston rod come loose at the piston and beat the engine to broken pieces like yours. The bad thing is that my insurance was for airplane damage and not engine damage. Like you I had no airplane damage. Landed on the highway near Santa Domingo Pueblo on the Rio Grande.


Thanks, I had the luxury of altitude, so it wasn’t too big a deal. Mainly I was thinking “Well now I have to fix this thing…”

Same for me re: insurance. Luckily had some good friends to lend a hand and trailer the bird home.
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Re: Broken crank on climb out

Well done sir!
That's nothing money can't fix!
MooseMeat offline
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Re: Broken crank on climb out

Ouch! But, good job handling a potentially ugly emergency! When/if you figure out what precipitated the destruction, let us know.

I had a crank fail in a C-185, NTSB took the engine, had it for almost two years and concluded that the crankshaft broke……not very helpful in understanding what happened.

I hope you can find an engine and get back in the air soon.

MTV
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Re: Broken crank on climb out

A1Skinner wrote:Wow, did the bolts on the adapter break or did they fall right out?
Good job on getting it down safely.


Those bolts just fell out… maybe all the vibration? But didn’t seem too bad at the time. Strange thing to me is that those were not safety wired, drilled bolts.
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Re: Broken crank on climb out

mtv wrote:Ouch! But, good job handling a potentially ugly emergency! When/if you figure out what precipitated the destruction, let us know.

I had a crank fail in a C-185, NTSB took the engine, had it for almost two years and concluded that the crankshaft broke……not very helpful in understanding what happened.

I hope you can find an engine and get back in the air soon.

MTV


That’s classic! Yep, so far it’s a mystery… externally everything looked a-ok (except for the oil filter adapter). It was a surprise to see all that carnage when we pulled the jug.

-Rob
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Re: Broken crank on climb out

LuscombeRob wrote:
A1Skinner wrote:Wow, did the bolts on the adapter break or did they fall right out?
Good job on getting it down safely.


Those bolts just fell out… maybe all the vibration? But didn’t seem too bad at the time. Strange thing to me is that those were not safety wired, drilled bolts.
I'd almost be willing to bet that those came out before this happened. If you were getting oil into the cabin before the loud bang when the crank broke, I'd bet the bolts were gone, then vibration caused the adapter to pop off the gasket, they usually stick on pretty hard, then the lack of oil is what caused caused rest of the carnage. Just my guess.
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Re: Broken crank on climb out

MooseMeat wrote:Well done sir!
That's nothing money can't fix!


Oh yeah, it’ll be a hit to the flying funds, but already sourced an overhauled O320!
Working on getting her back together…
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Trailering home from Kansas
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Friends helping reinstall the wings
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Pulling the “boat anchor”
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Re: Broken crank on climb out

A1Skinner wrote:

I'd almost be willing to bet that those came out before this happened. If you were getting oil into the cabin before the loud bang when the crank broke, I'd bet the bolts were gone, then vibration caused the adapter to pop off the gasket, they usually stick on pretty hard, then the lack of oil is what caused caused rest of the carnage. Just my guess.



That’s kinda the way we were leaning… My one glance at the oil pressure gauge showed all normal but then I was padlocked on flying the bird and honestly never went eyes in until I was on the runway.
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Re: Broken crank on climb out

I'm not a mechanic David (A1Skinner) but I think you are right. My piston rod came loose at the piston. Wrist pin, I think, is what the mechanic said. So I kept my oil and the engine kept running although very loud banging. I almost shut down, but was busy with the landing anyway. The engine was rebuilt. I think the case was replaced. It was $4,000 in the late 70s. A mechanic who sent it elsewhere for rebuild and I pulled the engine on a really cold and windy day and we both put it back on. I had to make the second forced landing. New plugs had evidently been dropped in rebuild he said.
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Re: Broken crank on climb out

LuscombeRob wrote:A1Skinner wrote:

I'd almost be willing to bet that those came out before this happened. If you were getting oil into the cabin before the loud bang when the crank broke, I'd bet the bolts were gone, then vibration caused the adapter to pop off the gasket, they usually stick on pretty hard, then the lack of oil is what caused caused rest of the carnage. Just my guess.



That’s kinda the way we were leaning… My one glance at the oil pressure gauge showed all normal but then I was padlocked on flying the bird and honestly never went eyes in until I was on the runway.
Yes I think at that point you did the right thing. Looking at the oil pressure guage would have just confirmed what you knew already.
On the topic of you saying you were surprised that those bolts weren't drilled for lock wire, keep in mind that many bolts on the engine aren't. The bolts holding the oil pan on, the case half bolts, and many other bolts don't. But they all have proper torque specs and have washers and lock washers on them. The filter adapter has the same washer stack up. I've never seen those bolts loosen up if new lock washers are used when they are removed and if the proper torque is used. Not to say it can't happen, but to have all 4 work there way out, I'd be a bit suspicious. There is a fair bit of thread engagement on those bolts.
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Re: Broken crank on climb out

Yes I think at that point you did the right thing. Looking at the oil pressure guage would have just confirmed what you knew already.
On the topic of you saying you were surprised that those bolts weren't drilled for lock wire, keep in mind that many bolts on the engine aren't. The bolts holding the oil pan on, the case half bolts, and many other bolts don't. But they all have proper torque specs and have washers and lock washers on them. The filter adapter has the same washer stack up. I've never seen those bolts loosen up if new lock washers are used when they are removed and if the proper torque is used. Not to say it can't happen, but to have all 4 work there way out, I'd be a bit suspicious. There is a fair bit of thread engagement on those bolts.


Yep, agreed… kind of suspect. I’m digging through past photos to see if I have anything that shows what it looked like prior to the failure.

-Rob
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Re: Broken crank on climb out

Wait a minute....why didn't you bail out? I thought that's what all we light aircraft pilots do when the motor quits? #-o
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Re: Broken crank on climb out

courierguy wrote:Wait a minute....why didn't you bail out? I thought that's what all we light aircraft pilots do when the motor quits? #-o


He got lucky, and his door didn't open. Otherwise he would have been sucked right out.
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Re: Broken crank on climb out

courierguy wrote:Wait a minute....why didn't you bail out? I thought that's what all we light aircraft pilots do when the motor quits? #-o



Haha I have a hard enough time climbing into that bird, much less climbing out!
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Re: Broken crank on climb out

Well done, very well done. Good reminder they can, and will quit too.

Look forward to hearing anything more you find on it.
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Re: Broken crank on climb out

Ardent wrote:Well done, very well done. Good reminder they can, and will quit too.

Look forward to hearing anything more you find on it.


Thanks… I don’t know if we’ll ever figure out why it blew up, but every time I look at it I’m impressed at the forces involved in tearing itself apart.

On the plus side, I’ve now got a zero time O320 hung on the motor mount and we’ll start getting everything reconnected.
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