Crankshaft Seal Blowout In Flight and Emergency Landing

[Gash]

Serious question...were you truly unaware of the need for regular inspection and cleaning, and the simple precaution of installing a relief valve?

Dan, on your first question, yes. Truly unaware. I think I read here a long time ago about this being a problem on RV-10s due to the long length of the exhaust pipe and potential cooling of exhaust gas into a temperature range that promotes carbon build up. But it didn't seem to be an issue with the shorter exhaust run on a 4-cylinder engine. Obviously this incident proves otherwise.

As for the relief valve, again I was unaware. Please direct me to a link where I can buy one. If none are available, then I'll fabricate one for myself. I don't know which was worse, figuring out how to land the airplane, or spending an entire day cleaning up the mess. I don't ever want this to happen again, so if there are further mechanical precautions that I can implement, then I'm going to do it.

[Ironflight]

Let me add my congratulations on a great job of handling the emergency - well done! Check your PM's Gash - I sent you a message.

This problem with coking up of the valve on the Anti-Spalt systems has been getting notice the past few months, and while Anti-Splat has maintained that it is only an RV-10 problem, we have had written reports right here on VAF of it happening in other models as well. Anti-Splat has ignored this - and now it nearly could have cost an airplane and a pilot.

I have talked with old-timers in the experimental airplane world who said that tried similar exhaust suction systems decades ago, and the valves coked up and seals blew out, so they decided the risk wasn't worth it - there is not much new under the sun, and designers who choose to ignore history are doomed to repeat it.

Based on the reports I have seen, I strongly urge anyone with one of these systems to install a relief valve (at the very least) right away. I too have dumped all the oil from an engine (due to a hose rupture, not a seal blow-out) - it is NOT a fun experience, and if you don't have an airport underneath you, it can end very badly.

Paul

[Gash]

Originally Posted by pierre smith

That's one reason that I have my blowby tube open...I'd rather clean the belly occasionally.

Pierre, that's certainly a valid point and a reasonable choice to make. The way I look at it now is that there's no free lunch here. I'm either going to clean the belly occasionally, or I'm going to clean out the valve fitting occasionally.

I also acknowledge that a dirty belly won't break an airplane, but a plugged valve could. I will accept that risk and take all precautions to mitigate it. I now understand that the oil separator is not an install-and-forget item. It will require regular inspection and cleaning, which I will now do without fail.

The big issue here is that I really did not know this was necessary, and I'm sure the manufacturer did not know either, else he would send out a service bulletin. I left him a message and I'm sure we will be in touch today to go over it. Allan is a super guy and I have no hard feelings whatsoever. My goal is to identify what installation and operating conditions cause risk, then to find a way to mitigate the risk, and finally to communicate this as widely as possible to the experimental aviation community.

[DavidBurton]

Congratulations on getting back on the ground safely. Kind of a Lindbergh landing huh? (He had no front window at all in the Spirit of St. Louis). Lindbergh would slip to final while looking out the side window.

My father had a similar experience in a Corsair. He was airborne from an aircraft carrier when a broken hose completely covered his windscreen with oil. His only option, other than to ditch in the water, was put it down on the carrier. He could see the ship by sticking his head out the open canopy, but couldn't reach the rudder pedals while doing that. He obviously made it, obviously because this was a couple of years before I was born...

[C. Brenden]

Great job on flying the airplane first! This is a great lesson for all of us to keep what's most important job one. FLY THE AIRPLANE! Good SRM lesson too. Use whatever resources available to you to solve the problem. Glad you are ok and be sure to say hi on frequency next time you talk to ABQ center!

[russ-e]

Hi, Great story glad it worked out for the best. I had a thought about the seal installation.
It seems to me that I have seen some with retaining plates for the seals using the 6 bolt holes in the front of the case. It would be easy to make some unless there is some reason not to, Just a thought?

Russ Emick,Jr.
Building RV-8

[BillL]

This is a little off the OP, but it goes to the issue of communications. While it is certainly the role of a responsible vendor to be aware of, and notify customers of potential safety issues, can it be done another way?

The huge convenience, instant accessibility, and participation of subject matter experts of VAF has overshadowed other communication paths. Vans can not be the center of this, too much liability. What if a white paper on this failure mode was written, how would some one find it buried in a thread under layers of comments?

Is there a way to post these things here negating all the legal pitfalls? Some way that a percentage of flyers can "agree" or otherwise respond with a collection of endorsing experts?

Recall a post by John Thocker about the Dynon freezing pitot? Even Dynon took their time in responding (12+ months?) but finally documented the issue properly.

Even if these reports, at best, become an awareness tool, isn't it better than leaving thousands of pilots in thousands of hours to rudely rediscover this on their own? Can EAA serve this function - those in the management of VAF and EAA - can you help us understand this?

OK, maybe not so short. Sorry.

[Sig600]

If you want to keep oil off your belly, buy a Lycon built motor.

Nice job Gash, I would not want to try and land my 8 "Spirit of St Louis" style under the gun for the first time.

[mburch]

Originally Posted by Gash

I also acknowledge that a dirty belly won't break an airplane, but a plugged valve could. I will accept that risk and take all precautions to mitigate it. I now understand that the oil separator is not an install-and-forget item. It will require regular inspection and cleaning, which I will now do without fail.

Just to be clear - the oil separator itself is not to blame in this case, just the valve that plumbs the breather into the exhaust, correct?

mcb

[russ-e]

Hi, I looked it up and Lycoming parts book show`s retaining plates #73952 take`s 2 oil seal retaining plates. With no bolt holes it takes seal part # 77377

Russ Emick,Jr.