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PostPosted: Sun Mar 11, 2018 11:33 am 
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Hi guys,

today I wanted to go for a nice flight with my Comanche over Germany. Just a quick sightseeing trip to the Zugspitze and then for a nice coffee to the Lake of Constance.

So I did my pre-flight check and everything looked fine. Enough oil and fuel and the last 50h check was only 16h before. I hopped in the cockpit and started the engine. It fire up immediately. Checked the oil pressure, fine. After a brief warm up I taxied to the run-up area. When I got there the engine was not quite warm enough for the run-up check so I let her idle at 800rpm while I was doing my takeoff briefing and looked at the planned route. The big flat six was purring like a kitten when I suddenly noticed a drop in rpm of maybe 50-100 rounds. I had the mixture leaned out to avoid spark plug fouling and it was a nice and rather dry day. So I was surprised at the rpm drop since I didn't expect any icing or fouling. So I checked the engine instruments and the oil pressure gauge read dead nothing :shock: Shock! I immediately pulled the mixture and turned off the magnetos.

The plane needed to be towed back to the hangar. The mechanic then told me that the crankshaft bearings were shot and the compression was down to the high 50s low 60s on all six cylinders. Basically a dead engine. It looks like the oil pump failed since there were still 9 quarts of oil in the engine and the oil pump was reported as a failed part by my mechanic too. So with all the damage on the engine I decided it was time for a complete overhaul.

I guess it was lucky that the oil pump failed on the ground and not during the takeoff run since there would not have been many options on a only 1600ft long runway with a seized engine.

Anyways I just thought I'd share my experience with you guys. Gotta love Accusim for keeping you on your toes!

Back to flying though since I have a new engine to break in :wink:

PS: I hope the next engine lasts a bit longer than 816h (not all put on by me).

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B377&COTS, J3 Cub, B-17G, Spitfire, P-40, P-51D, C172, C182, Pa28, Pa24, T-6 Texan, L-049&COTS


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PostPosted: Sun Mar 11, 2018 1:03 pm 
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Location: Arendal, Norway
Cool story!

Not all failures happen during takeoff when there is no runway left or altitude enough to turn, sometimes they just happen when you have all the time in the world.

I had something similar happen to the Cherokee around 60 hours after I got it. It happened during back-taxi to the runway, so relatively close call, but not dramatic. It could have been deadly - the runway was 21 at Kjevik, Norway (ENCN). It leads directly to water, with no options other than return to the field.

Now, with an Accusim twin, we'd all be hoping for that blue-line practice, I'm sure. May a twin-trainer be in the works and ready for release yesterday! :)

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Erik Haugan Aasland,

Arendal, Norway
(Homebase: Kristiansand Lufthavn, Kjevik (ENCN)

All the Accusim-planes are in my hangar, but they aren't sitting long enough for their engines to cool much before next flight!


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PostPosted: Sun Mar 11, 2018 2:39 pm 
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Thanks Erik. Yes you’re right not all accidents happen during takeoff. Mostly failures to the core engine will happen most likely during takeoff in my opinion due to the high loads on pistons valves and so on.

I actually couldn’t resist to take advantage of a simulator and try to see what would have happenend if I would have continued. So I fired the Comanche back up and the engine seized and stopped completely before I even got on the runway. So if I wouldn’t have caught the non existing oil pressure I would not have made it of the ground. :|

Happy flying
Sebastian

Edit: fixed typo

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B377&COTS, J3 Cub, B-17G, Spitfire, P-40, P-51D, C172, C182, Pa28, Pa24, T-6 Texan, L-049&COTS


Last edited by Piper_EEWL on Mon Mar 12, 2018 1:21 am, edited 1 time in total.

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PostPosted: Sun Mar 11, 2018 5:11 pm 
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Hi,

Great experience Sebastian, thanks for sharing with us! I have one question to you and Erik.
Did you guys receive any indication in the hangar, that what you experienced was about to happen? Usually it should be a warning from the mechanic and a colored in yellow part, right? I only experienced sudden part failure in the B-17, where a cylinder got blown during flight in one of the engines.

Cheerz,
Will

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PostPosted: Sun Mar 11, 2018 5:19 pm 
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Thanks Will,

For the last two or three scheduled checks the mechanic was reporting metal in the oil and was saying that we need to keep an eye on the crank shaft. But no indication that the oil pump would fail. The oil pressure was building quickly after startup and it was very stable even with a hot engine. So I wouldn’t have suspected something to go so wrong.

But I actually know of a RL Mooney 252TLS that had a catastrophic oil pump failure during flight. So it doesn’t seem to be unheard of.

Happy flying

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B377&COTS, J3 Cub, B-17G, Spitfire, P-40, P-51D, C172, C182, Pa28, Pa24, T-6 Texan, L-049&COTS


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PostPosted: Sun Mar 11, 2018 8:13 pm 
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LZ-WIL wrote:
Hi,

Great experience Sebastian, thanks for sharing with us! I have one question to you and Erik.
Did you guys receive any indication in the hangar, that what you experienced was about to happen? Usually it should be a warning from the mechanic and a colored in yellow part, right? I only experienced sudden part failure in the B-17, where a cylinder got blown during flight in one of the engines.

Cheerz,
Will


Oh, but this question reveals a bias towards checking the hangar before flying. I never do that. I only fly to airport with the relevant service center (for example Long Beach in SoCal is the place for my Cessna 172 at the moment) for the regular services, so I never ever open the hangar as per normal procedures. I rely on preflights, flying by the book, and knowing how the airplane is supposed to perform and thus noticing deviations.

Try it! It demands rigorous self control to not open the hangar to take a peak, but it is extremely rewarding to not have the warnings from a mechanic.

_________________
Erik Haugan Aasland,

Arendal, Norway
(Homebase: Kristiansand Lufthavn, Kjevik (ENCN)

All the Accusim-planes are in my hangar, but they aren't sitting long enough for their engines to cool much before next flight!


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PostPosted: Mon Mar 12, 2018 1:25 am 
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I do the same thing with the GA fleet. I only check the hangar for scheduled maintenance or if I get a indication that something is seriously wrong either during the pre-flight checks or during operation. I try to keep it as close as possible to real world operations.

And yes Erik you’re correct. It is very satisfying when you actually catch a issue just from noticing what’s different other than the mechanic telling you what’s wrong.

Happy flying

_________________
B377&COTS, J3 Cub, B-17G, Spitfire, P-40, P-51D, C172, C182, Pa28, Pa24, T-6 Texan, L-049&COTS


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PostPosted: Mon Mar 12, 2018 2:07 am 
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Medtner wrote:

Oh, but this question reveals a bias towards checking the hangar before flying. I never do that. I only fly to airport with the relevant service center (for example Long Beach in SoCal is the place for my Cessna 172 at the moment) for the regular services, so I never ever open the hangar as per normal procedures. I rely on preflights, flying by the book, and knowing how the airplane is supposed to perform and thus noticing deviations.

Try it! It demands rigorous self control to not open the hangar to take a peak, but it is extremely rewarding to not have the warnings from a mechanic.


Hello Erik and Sebastian,

Given your explanation, yes I do check the hangar more than you do, but not on every flight. I check it only on airports, like Erik said where it could be checked and every fifth or sixth flight for a given aircraft. I will take Erik's advise and check it more seldom. :wink:

Thanks,
Will

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PostPosted: Mon Mar 12, 2018 4:01 am 
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Just pretend like you have to pay the mechanic and you’ll automatically will check the hangar less often :wink: :D

Happy flying

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PostPosted: Mon Mar 12, 2018 4:16 am 
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Piper_EEWL wrote:
Just pretend like you have to pay the mechanic and you’ll automatically will check the hangar less often :wink: :D

Happy flying


Sure, will do. :)

:mrgreen:
Will

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