Author Topic: Bodhi, A&P questions for ya  (Read 637 times)

Offline Wolfala

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Bodhi, A&P questions for ya
« Reply #15 on: February 14, 2008, 05:38:38 PM »
Well,


Lets give the update while I can still think somewhat clearly. In addition to the the cylinders #3 and #2 which were diagnosed with Valve and Piston Ring problems - over the last few days during test runs at the maintenance facility and evaluating the data:

We have the TCM Valve Disease on Cylinders 1, 3, 5, 6 where it did not exist before the engine run on 1/30. The classic tell tale signs before you get failed compressions are EGT jitters such as the one below showing Cylinder #1 EGT. Notice how it looks like an EKG.

#1 also has elevated CHT levels and low EGT on a couple of runs. If I had a place to post the files I would, but picture hanger appears down. I'll post up what I can on other sites.



The first image is what you are seeing in flight. That is the tell tale signs of a valve which isn't closing completely and is leaking. Now this is the #1 cylinder and it passed compression during the examination. But this is the beginnings of valve failure when you begin to see the jitters.



The second image is a little bit different, but just as serious. It is called "Morning Sickness" and though it more often seen in Lycoming engines - basically what it means is the exhaust valve is either stuck in the OPEN position or the CLOSED position. You can't really tell, but when the engine starts it shows its sign by usually having a rough ride the first 30-45 seconds and then smoothing out. When viewing the data section, you can see EGT #5 and #6 with temperatures underneath them of 144, and 168. Those temps are more then likely a result of the compression taking place inside the cylinder, but the cylinder is not firing yet. Between 26:54 and 27:06 none of them are firing, but after that you can see the temperatures slowly come up as the valve unsticks itself until the temperatures have more or less equalized themselves about 30 seconds after start. Open or closed - they are both bad for a couple of reasons. If open, the piston runs the risk of striking the valve and bending things that shouldn't ever be bent.

So, with 5 out of 6 cylinders showing problems that were not there prior to the run on 1/30, it looks like a Top Overhaul is most likely going to be the future for this engine.

I spoke with Bill Cunningham of Powermaster Engines out in Tulsa - he's done a couple of rebuilds for a few friends of mine - when the old jugs come off we'll inspect the Lifters and Cam lobes for signs of spalling. If that shows up - well, I think I'll just have another drink and send the bill to insurance.

Thats the news from this side of the world. I think the JPI has more then paid for itself at this point.

Wolf

P.S.  If anyone is interested in getting more indepth analysis on this, you can download the analysis software for free at http://www.jpitech.com/Downloads/EzTrends_setup.exe

I can then send you the data files and you can have a see for yourself.
« Last Edit: February 14, 2008, 05:49:25 PM by Wolfala »


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Offline LePaul

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Bodhi, A&P questions for ya
« Reply #16 on: February 15, 2008, 12:07:50 AM »
Was the renter not aware of how to properly fly the airplane?

It really looks like his one jaunt did a heck of a lot of damage to your plane  

Any recourse thru the renter insurance?

Offline Wolfala

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Bodhi, A&P questions for ya
« Reply #17 on: February 15, 2008, 12:24:40 AM »
The short answer to your question is - as a leaseback owner, I have commercial insurance which covers the aircraft (myself) - not the pilot flying it. In a case of negligence, or careless and reckless operation, the insurance company would look for evidence that they were operating the equipment in an improper manner (which we have data), and the end results of that operation (more data, hours and hours), and results of inspections and other means of inspection (DATA in this case). The irony of it is, the borescope and compression test inspections found problems with 2 cylinders. It took further running of the engine and recording of its operational parameters to pickup on the other 4 cylinders that were dying slowly. What that means in legalese, is the pilot - if he does not have renters insurance - after my insurance gets done settling with me the damage claim - they would subrogate and sue him to recover the damages they have paid out. If he has renters insurance, the amount he would be getting sued for could theoretically be covered. If not - they will sue him and go after his assets.

Various screen caps from other events found through the process of discovery.









the best cure for "wife ack" is to deploy chaff:    $...$$....$....$$$.....$ .....$$$.....$ ....$$

Offline Wolfala

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Bodhi, A&P questions for ya
« Reply #18 on: February 15, 2008, 12:26:00 AM »








These caps are valves in various states of failure.


the best cure for "wife ack" is to deploy chaff:    $...$$....$....$$$.....$ .....$$$.....$ ....$$