Lost a prop governor in-flight today...

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mtuomi

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This is turning out to be a great trip...

Flying from KIWS to KMEM, and somewhere in the absolutely middle of nowhere, TX, engine suddenly surges to redline. Prop lever does pretty much nothing so to prevent it from overspeeding had to drop power down to around 18 inches, which barely kept us in the air.
Closest diversion was ab 50 miles away, so turned towards it and started getting slightly nervous when oil pressure started dropping. Anything above around 17-18 inches would redline the prop.

Landed, had just over 3qts of oil left (was at 6 when we left). Nothing obvious that I could see, but didnt take the cowling out yet.

Any guesses what it would be? (Arrow II)

Getting good abnormal situation practice on this trip!
 
Art VanDelay said:
Failed prop governor ?
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Yep I think thats what it was. Will be interesting to learn what the damage mechanism is.
Will try to find a mechanic in middleofnowhere, TX (KLFK) and see what happens tomorrow. Now I deserve a beer or fifteen.
 
Didn't you just have a mag fail catastrophicly on you too? You might want to reconsider the maintenance of the operation you're renting from.
 
Brad Z said:
Didn't you just have a mag fail catastrophicly on you too? You might want to reconsider the maintenance of the operation you're renting from.
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Mag didnt fail, it just sort of fell off :)

But yes - same plane, same trip, ab 5 hours flying between these events. Fun...
 
Brad Z said:
Didn't you just have a mag fail catastrophicly on you too? You might want to reconsider the maintenance of the operation you're renting from.
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That.

Sounds like you're burning through your nine lives rather fast.
 
also consider you might have run too low on oil to keep the prop governor fed...
If you don't find an obvious problem (cockpit control unhooked, broken feed line, ect.) put oil in it and try to cycle the prop. If it works OK ground the plane until the cause and effect(s) of the missing oil are determined.


Chris
 
Hiperbiper said:
also consider you might have run too low on oil to keep the prop governor fed...
If you don't find an obvious problem (cockpit control unhooked, broken feed line, ect.) put oil in it and try to cycle the prop. If it works OK ground the plane until the cause and effect(s) of the missing oil are determined.


Chris
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Thats another possibility, but I would have expected this to cause rpm creep, not a sudden surge as what I experienced?
 
write-stuff said:
First thing that came to my mind, too.
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Me too. Lack of sufficient oil in the system can result in governor failure.

I would look into why the oil was so low first. Once that has been addressed, see if the governor is still not functioning.

In a single engine, a loss of oil pressure will drive the blades to flat/fine pitch which will result in the overspeeding you saw. You get the opposite effect in a twin.
 
How did you get down to 3 quarts of oil? How much did you take off with? How long were you flying?
 
mtuomi said:
Thats another possibility, but I would have expected this to cause rpm creep, not a sudden surge as what I experienced?
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Nope, once it catches air and cavitation, it "loses traction" and the spring or counterweights drive it hard.

Where did the oil go? Was it never refilled after the mag?
 
Henning said:
Nope, once it catches air and cavitation, it "loses traction" and the spring or counterweights drive it hard.

Where did the oil go? Was it never refilled after the mag?
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In the OP, he said he had six when he left.
 
John221us said:
In the OP, he said he had six when he left.
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Ok, where did three quarts go in how long? The prop surge got you to the ground before the engine toasted, now figure out why the engine almost toasted. Pull the prop through all 4 or six cylinders and see if they all have the same basic resistance. Look at the belly, it it coated?
 
mtuomi said:
I know, I already had that much out once during this trip :)

Nothing visible, which is sort of worrying.
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Look at the belly? Dry? Pull the prop through an look for any significant difference in compression resistance. Is the exhaust pipe residue dry or oily? 3qts in 1.5 would look like you had 'smoke on'.
 
mtuomi said:
Yep, had six, now have 3, maybe 1.5hrs flying.
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Consider yourself lucky. That CS prop saved you.

A few years ago we took off with 6 qts in an O360 and 15 min's later the engine failed due to insufficient oil. For some reason, the oil decided to take residence on the outside of the engine rather than the inside and since we had a fixed pitch prop, the first we noticed were extreme CHT's and Oil Temp and diminished oil pressure and power; quickly followed by extreme banging and knocking and then complete silence as the prop came to a stunning and instant halt. We had to put her down on a highway between power lines and a drainage ditch during rush hour. My wife did a great job on that landing with less than 100 hrs logged up till then.

We never did find out what happened because the engine was grabbed by the inspectors and we never saw it again. But I am sure we had good maintenance.

Assuming you are renting, I believe I would call the owners of the plane and tell them where they can find it. I hope you didn't pay in advance.
 
JOhnH said:
Consider yourself lucky. That CS prop saved you.

A few years ago we took off with 6 qts in an O360 and 15 min's later the engine failed due to insufficient oil. For some reason, the oil decided to take residence on the outside of the engine rather than the inside and since we had a fixed pitch prop, the first we noticed were extreme CHT's and Oil Temp and diminished oil pressure and power; quickly followed by extreme banging and knocking and then complete silence as the prop came to a stunning and instant halt. We had to put her down on a highway between power lines and a drainage ditch during rush hour. My wife did a great job on that landing with less than 100 hrs logged up till then.

We never did find out what happened because the engine was grabbed by the inspectors and we never saw it again. But I am sure we had good maintenance.

Assuming you are renting, I believe I would call the owners of the plane and tell them where they can find it. I hope you didn't pay in advance.
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You have to love how engines always disappear so you have no evidence to sue with. They end up right in the hands of the manufacturer.
 
Henning said:
You have to love how engines always disappear so you have no evidence to sue with. They end up right in the hands of the manufacturer.
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NO kiddin.....

Personally I would retain ownership of the ruined motor till I had time to document what the hell happened.... Then , if the inspectors and insurance company wanted it... I would gladly release custody of the entire mess..
 
He'll find the control disconnected. There's a spring on the governor lever that takes it to full RPM, and he said that working the control made no difference after the failure. I'd suspect that if the mags were loose, the control connection wasn't safetied either. Better have a look over that whole engine. Maybe the whole airplane.

Dan
 
Dan Thomas said:
He'll find the control disconnected. There's a spring on the governor lever that takes it to full RPM, and he said that working the control made no difference after the failure. I'd suspect that if the mags were loose, the control connection wasn't safetied either. Better have a look over that whole engine. Maybe the whole airplane.

Dan
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Had that in the Lake Bucaneer on my CSES/SEL check ride. I had a cotter pin in my pocket and fixed it floating there on the lake. He waived one of the checkride fees for that.:D
 
Dan Thomas said:
He'll find the control disconnected. There's a spring on the governor lever that takes it to full RPM, and he said that working the control made no difference after the failure. I'd suspect that if the mags were loose, the control connection wasn't safetied either. Better have a look over that whole engine. Maybe the whole airplane.

Dan
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Possible, but how do you explain the loss of oil at the same time? Low oil and consequently oil pressure will also drive the prop blades to flat pitch in a single and a lack of sufficient oil pressure would also result in failure of the prop lever to do anything.
 
Controls etc are connected. My strongest guess at the moment is low oil pressure, even though it was within the green arc.

The worrying thing is - where is the oil going?
 
mtuomi said:
Controls etc are connected. My strongest guess at the moment is low oil pressure, even though it was within the green arc.

The worrying thing is - where is the oil going?
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Interesting that you experienced that with the oil pressure still within the green.
 
Did you pull the prop through two full revolutions to do a rough judgement of compression? Unless oil is dripping off the engine or the belly, you have it going out the exhaust valve. Find the oil, it's either in the cowl, on the belly, or in the exhaust pipe.
 
Fearless Tower said:
Interesting that you experienced that with the oil pressure still within the green.
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Yep, and during the previous incident the oil level got much lower and gov still was working.

Manual doesnt specify anything apart from the 2qrt min safe oil, I assume this should be enough for the governor to operate correctly too. And its never been anywhere nearly that low.
 
Me thinks you need to find a better place to rent!

This is one of those times it is good to NOT be the owner.
 
mtuomi said:
Yep, and during the previous incident the oil level got much lower and gov still was working.

Manual doesnt specify anything apart from the 2qrt min safe oil, I assume this should be enough for the governor to operate correctly too. And its never been anywhere nearly that low.
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It all depends if it got a slug of air in turbulence or not. Did you ever try cycling the prop after it went flat pitch?
 
Henning said:
It all depends if it got a slug of air in turbulence or not. Did you ever try cycling the prop after it went flat pitch?
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I spent ab 20 minutes trying just about every trick in the book. The blue lever was dead. Now after refilling the oil it seems working. Will test more...
 
mtuomi said:
I spent ab 20 minutes trying just about every trick in the book. The blue lever was dead. Now after refilling the oil it seems working. Will test more...
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Sometimes those systems just bleed funny. The question is, where did the oil go? Have you found it yet, or have you abandoned the plane? :lol: That is the thing about rental, you call them up, "your plane is broke."
 
Governor failure, will be replaced tomorrow.
 
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