Crankshaft failure in flight, lost propeller, no injuries
Posted: Wed Nov 15, 2023 12:46 pm
by Ethanm
The saga continues…
After spending 4 days stuck in Ohio facing ignition and vapor lock problems (both resolved thanks to the help of some A and Ps and these forums), I departed solo on my way back home to Maine. In the final 20 mile stretch flying from KPOV to KOLE I started experiencing some minor vibrations. I tried adjusting mixture and power settings, and running on either ignition to no avail. Within 2 minutes the vibrations had increased to the point that the entire instrument panel was unreadable. At this point I switched to 121.5 and my propeller, spinner and, flange completely departed the aircraft. The engine spooled up after this and ran fine. I declared an emergency and glided to a road underneath me. Luckily landed safely with no damage to the airframe or anything on the ground. Crankshaft cracked right at the front main seal. Prop bolts had been retorqued ~20 flight hours before. The engine had the older model of crankshaft, was not an aerovee 2.1. Unsure if this potentially is related to the crankshaft failure. Very glad to have had a long straight road right underneath me, and that this resulted in the safest possible outcome. Bummed the plane will be down for the foreseeable future 
Images after landing:
https://postimg.cc/gallery/nBwXgpj
Some news articles:
https://www.oleantimesherald.com/news/f … e9e0d.html
https://wellsvillesun.com/blog/2023/11/ … us-county/
https://www.nyspnews.com/emergency-land … te-417.htm
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Wed Nov 15, 2023 9:13 pm
by BobDz
I am so glad that you are safe!
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Wed Nov 15, 2023 9:19 pm
by tps8903
Glad you landed safe. I could have swore that was a low time engine despite being older. Strange to me the crank broke. Was there a prop strike or something in the history?
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Wed Nov 15, 2023 10:39 pm
by Bryan Cotton
Wow! And great job!
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Thu Nov 16, 2023 9:05 am
by kmacht
Great job in walking away from that one. There were a few crank failures on aerovees years ago. I believe that they all had either a prop strike or someone improperly assembñed or disassembled the shrink fit hub to the crank. As you are finding out, the groove in the crank right behind the back of the hub is a weak spot. If you ever locate the prop and hub you will probabñy find the crack initiated around the keyway and progressed back to that groove. If you decide to stick with a vw take a look at the force 1 prop hub and crank. You may be able to salvage the case when it’s machined for the large bearing that hub uses. Great Plains sells the crank and hub and I had hummell do the case machining for me on motor.
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Thu Nov 16, 2023 9:26 am
by DCASonex
Glad you are okay.
I have a Sonex, but with a A CAMit 3300 not an Aerovee, in a hangar at KOLE, (Cattaraugus Co / Olean Airport) and a decent workshop in there. My hangar is a new one but non-insulated steel so not the best for working in winter, but the main hangar there has space and is heated. Also have a flat bed trailer outfitted to haul a tail dragger Sonex. and a well equipped home shop a few miles from there. Can TEXT (not voice) me at seven one six- 498-one five seven zero if I can be of help.
David A.
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Thu Nov 16, 2023 9:30 am
by bvolcko38
Very well done!!!
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Thu Nov 16, 2023 9:38 am
by Tony4aro
Glad you are safe… the rest can be fixed
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Thu Nov 16, 2023 10:51 am
by builderflyer
Ethan…what a once in a lifetime trip you’ve had and at such a young age. Congratulations on doing what was needed to get the plane on the ground safely. With all that’s happened on this trip, I think you’ve probably learned firsthand why flying some of these airplanes at night or in IFR conditions is not such a good idea. Again, great job. I wish you good success going forward.
Art,Sonex taildragger #95,Jabiru 3300 #261
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Thu Nov 16, 2023 11:11 am
by Bryan Cotton
I have not heard of crankshaft failures recently. I remember there was at least one discussed on the forum years ago. Seems the new cranks or hubs are better. I sprung for the assembled crank rather than pressing on my own hub, though I’m sure I could do it.
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Thu Nov 16, 2023 11:21 am
by Dave Wolfe
Congrats on a safe outcome!
How many hours were on the engine?
The 2.1 crankshaft and hub use a smaller diameter bolt so crankshaft failure is less likely. Failures originate with cracks between the keyway and inner diameter of the prop hub main bolt.
This page shows the two different crankshafts:
https://onex-svingenb.blogspot.com/p/pr … s.html?m=1
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Thu Nov 16, 2023 12:10 pm
by jerryhain
As a flight instructor, I would like to congratulate you on maintaining your cool and keeping your situational awareness. Very few pilots get to experience a true emergency. Out of curiosity, do you happen to be a glider pilot as well?
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Thu Nov 16, 2023 7:32 pm
by peter anson
jerryhain wrote:Out of curiosity, do you happen to be a glider pilot as well?
If he wasn’t before, he is now.
Congratulations on getting down safely in what was obviously challenging conditions.
Peter
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Thu Nov 16, 2023 10:43 pm
by tps8903
peter anson wrote:
jerryhain wrote:Out of curiosity, do you happen to be a glider pilot as well?
If he wasn’t before, he is now.
Congratulations on getting down safely in what was obviously challenging conditions.
Peter
Involuntary glider pilot life achievement unlocked.
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Thu Nov 16, 2023 11:05 pm
by Weatherpilot
Nice job getting her down. Any idea where the prop/spinner/crank ended up?
Again - great aviating. My hat’s off to you.
Greg.
Re: Crankshaft failure in flight, lost propeller, no injurie
Posted: Fri Nov 17, 2023 12:54 am
by karmarepair
Please take pictures of the fracture surface of what’s left of the crank, both from a bit of a distance, and from as close as possible. The fine scale details of the fracture surface can tell a LOT about how the failure started.