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Old 10-27-2014, 12:50 AM
Gash's Avatar
Gash Gash is offline
Join Date: Aug 2009
Location: Goodyear, Arizona
Posts: 963
Default Crankshaft Seal Blowout In Flight and Emergency Landing

Last Thursday while flying from Goodyear, Arizona to Boulder City, Nevada the crankshaft seal on my IO-375 blew out. The windscreen on my RV-8 became completely covered in oil in about 10 seconds and I was unable to see anything out the front. Oil pressure remained in the green, but at the rate oil was coming out the front of the airplane, I knew it wouldn't last long.

I was approximately 13 miles west of Kingman, Arizona at 6,500? MSL when this happened. I made a right turn to east and began a descent to the Kingman airport. At the same time, I selected ?Nearest? airport on my Dynon Skyview map display to give me a magenta line to follow since the only thing I could see from 10 to 2 o?clock was thick brown.

I got a Southwest Airlines crew overhead to relay my position and situation to Los Angeles Center in case I didn't make it to the airport for some reason. Out in this part of the desert, 6,500? is sometimes too low to communicate directly with ATC, and sure enough, I could hear LA Center, but they couldn't hear me.

Winds were calm at Kingman, so I chose Runway 21 due to its 150 ft width. I made a quick call on Kingman CTAF to see if there were any other aircraft up that I could do a formation landing with, but nobody else was around. For the first time in 30 years of flying, I was seriously concerned about my chances of getting the airplane on the ground safely. Nothing focuses the attention and heightens the senses like oil gushing over the windscreen and not knowing when it will run out.

I flew slightly south of the airport and set up for a left downwind. I could see alright out the side of the plane, just not out front. After turning final, the Skyview runway picture on my primary flight display really helped out with blind flying. I put the flight path marker on the numbers and drove it in. Of course, the tricky part was the landing. I descended very slowly and looked out left and right repeatedly to make sure I was approximately equidistant from the runway edges on either side. Touchdown was uneventful, and oil pressure was still good so I exited the runway and shut down on the ramp.

A download of my Skyview flight data shows that from the first indication of a problem until touchdown at Kingman was 5 minutes 30 seconds. A post flight check of the oil quantity showed 3 quarts remaining. I started the flight with 6 quarts. So I was leaking oil at about a half a quart a minute. If the crankshaft seal had blown out somewhere else over the Arizona desert where airports are few and far between, there is no way I would have made it to a runway, so I was quite lucky.

The next day, Air?Zona Aircraft Services at Kingman repaired the blown crankshaft seal and helped to troubleshoot the cause. I have an Anti Splat Aero oil separator that uses a crankcase vacuum valve attached to an exhaust pipe. I am very happy with the oil separator and it has always worked exactly as advertised. The inside of the fitting that connects the valve to the exhaust had heavy carbon deposits and was restricted to about 1/8? diameter, certainly enough to cause crankcase over pressure. The fitting has been installed for 24 months and has never been internally inspected. There were no other blockages in the oil separator or hoses to and from the engine. I will now clean out the valve fitting at each oil change. I believe there has been some discussion on this potential problem here.

The risk of crankshaft seal failure caused by carbon buildup inside the vacuum valve fitting should be reemphasized. That?s really the big lesson learned from this episode. I always run lean of peak and my EGTs are typically around 1200 F. I would be interested to know if there is a correlation between exhaust temperature and a tendency for carbon deposits to form inside a valve-to-pipe fitting.

The other point to ponder here is about maintaining aircraft control. I will not patronize the readers here with the oft-quoted platitudes on the subject. However, I will say that for the several seconds during which I had not yet formed a plan for getting my pink butt on the ground, it was comforting to know that I was at least pointed at the nearest airport, and I was at least flying the airplane. The rest of the particulars of how to land rubber side down eventually worked themselves out.

Karl, Goodyear, Arizona (KGYR) ATP, CFII
Yak 50 Red Thunder Airshows
=VAF= donor 2022
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Old 10-27-2014, 01:00 AM
SebsRV7A SebsRV7A is offline
Join Date: Jul 2005
Location: Henderson, NV (KBVU)
Posts: 129
Default Well Done!

Great report. Great reminder to keep flying the airplane!
Seb Trost
Boulder City, NV
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Old 10-27-2014, 01:00 AM
erich weaver's Avatar
erich weaver erich weaver is offline
Join Date: Aug 2006
Location: santa barbara, CA
Posts: 1,762

Wow. That is gnarly. Sounds like you kept a cool head. Great job getting her on the ground safe and sound.
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Old 10-27-2014, 01:01 AM
Mike S's Avatar
Mike S Mike S is offline
Senior Curmudgeon
Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 16,167

Karl, glad you kept your head, and got it on the ground safely.
Mike Starkey
VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
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Old 10-27-2014, 01:07 AM
rvmills's Avatar
rvmills rvmills is offline
Join Date: Nov 2007
Location: Georgetown, TX
Posts: 2,156

Nice job Gash! Well done bro!

Bob Mills
RV-S6 "Rocket Six" N49VM
Cross Country-Marshall Field (07TS)
Georgetown, TX
President/Sport 49, Sport Class Air Racing
Trustee, Formation Flying Inc (FFI)
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Old 10-27-2014, 02:26 AM
rhill rhill is offline
Join Date: Feb 2006
Location: Valley Forge, Pa
Posts: 671

Glad you got down in one piece.I see retaining plates for the front seal on ebay from time to time,something to consider.
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Old 10-27-2014, 03:40 AM
Bevan Bevan is offline
Join Date: Sep 2007
Location: BC
Posts: 1,722

Good job on flying the plane.

Question: Is the seal glued in or just pressed in? If you landed off in the middle of no where, could the seal be pushed back in by hand and flown back to civilization (assuming the vent blockage was identified and cleared and you had some replacement oil to add) , or is the seal damaged in some way?

RV7A Flying since 2015
O-360-A1F6 (parallel valve) 180HP
Dual P-mags
Precision F.I. with AP purge valve
Vinyl Wrapped Exterior
Grand Rapids EFIS
Located in western Canada
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Old 10-27-2014, 04:47 AM
rwtalbot rwtalbot is offline
Join Date: Feb 2006
Location: Sydney, Australia
Posts: 256

Well don't getting it down. That's a great result.

You're obviously a calm guy. If I had that experience caused by an aftermarket part I might removing it for good.
Richard Talbot
Sydney, Australia
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Old 10-27-2014, 05:51 AM
pierre smith's Avatar
pierre smith pierre smith is offline
Join Date: Jan 2005
Location: Louisville, Ga
Posts: 7,912

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

Rv10 Sold
46 years ag pilot/CFI
Air Tractor 502/PT-6
Building RV-12, Wings, fuse, emp complete. FWF in progress.
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Old 10-27-2014, 05:59 AM
Steve Melton's Avatar
Steve Melton Steve Melton is online now
Join Date: Apr 2011
Location: Cincinnati, OH
Posts: 3,587
Default cleaning the belly

I was cleaning the belly last night thinking about a better way. I think I'll keep cleaning the belly.

Good write up and pictures and above all good flying!
Steve Melton
Cincinnati, OH
RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 900+ for all

Simplicity is the art in design.
I was born an airplane nut. I have no explanation for it.
My Artwork is freely given and published and cannot be patented.
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