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Really scary day

frankh

frankh

Well Known Member
Did some IFR training today...Things were going great then the weather closed in behind us an I got to learn what an "Alternate" was for.....so over the mountains we go to land at a seaside town called Newport Oregon.

Did some ground instruction, weather lifted back home and we're on our way...OK it was a lot more time than we would have liked but oh well.

On the way back over the mountains we get to within 30 miles of home and by now we're VFR on top of nice fluffy clouds when the engine temps went way high...Like i pulled the power so I was maintianing 90kts and just holding altitude at redline oil temp and #4 CHT just under redline.

two options, shoot the approach or return to our alternate over very unhospitible terrain.

we shot the approach (500 foot overcast) and landed safely.

so OK why hi oil temp and all the CHT's high?...esecially #4 (my hottest usually anyway)...expecting to find a dead rat stuffed between my #4 pot and oil cooler inlet, we pull the cowl and plenum...Nothing, all the baffles where they should be, good compression on all 4 cylinders.

For the life of me I can't see a connection between the high CHT and redline oil temps.

The only thing it could be is the Dynon engine monitor...and we did notice a couple of jumpy tach readings in flight.

So does anyone have any thoughts?

The one thing it taught me is IMC is serious stuff, I felt very fourtunate to have the CFI to manage the navigation while I flew the engine monitor...Of course if it was me alone (with much more experience) I think I would have gotten to the "Screw the engine, fly the plane and hope it don't blow up" mode as there were very few options to be honest.

Frank...My hands have stopped shaking now!
 
Bad engine block ground? Anyway, glad you are OK. Always revert to that screw the engine mode if engine "data" comes between you and flying the plane. Always remember, Aviate, Navigate, Communicate... In that order.
 
very scary indeed

I've got a 7A coming by Friday of next week and planned to use the Dynon as my EMS system. FrankH..... I read your post with great interest. It really seems to me that with the other insturmentation quirks you noticed, you may have had a moniter problem. What's the common denominator here, I don't know. It does make me think that if you had had a basic old standby type oil temp gauge which had a normal reading on it, you'd have felt more comfortable about proceeding. Kinda making me think I might put one in now. GLAD YOU AND YOUR CFI AND THE PLANE ARE SAFE!!! What are your thoughts on haveing the basic back up instrument???

Paul Gray
RV 7A QB
Foley, Alabama
 
Whooo

When I am IFR on one engine by my self, that's an emergency, because it means one engine has failed and the first officer has passed out. :D Nice to have back-up. Let us know what you find out with the high CHT/Oil Temp readings. It sounds like instrument failure? Unless the rats where flying flew in and blocked both cowl inlets.
 
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Sounds like grounding to me, too

Stephen said it. When lots of things get goofy at once, think grounds. If your sensors rely on engine ground instead of dedicated wires, it makes sense. You should have redundant ground braids from engine to system ground if you are using electronic instrumentation.

Sounds like you guys did just fine, managed the problem and used each other to effect a solution to the problem. Good aviating!

BTW If you find out what caused the issue, post it. I would be most interested.

John
 
frankh said:
.......when the engine temps went way high...Like i pulled the power so I was maintianing 90kts and just holding altitude at redline oil temp and #4 CHT just under redline.

For the life of me I can't see a connection between the high CHT and redline oil temps.

So does anyone have any thoughts?
Click to expand...

Frank,

Do not write it off as an indication problem just yet. Lycoming engines have an endearing quality of giving an early warning when something is not quite right.

Forgive my ignorance if this observation is off the page, but isn't the oil cooler located near the #4 cylinder? You could have a major problem with the #4 jug which caused the high oil temperature which in turn caused the other CHT's rise.

Some time ago, I was flying with a friend in his TriPacer and we noticed an unusual oil pressure indication that appeared out of the blue. In fact, we landed at an airport not at home, pulled the cowl to check things over, found nothing amiss, plenty of oil, took off and flew home. The oil pressure remained low but it was well off the peg.

The next day the oil screen was found it full of metal. The cylinders were pulled one at at time and there it was. One piston pin plug was missing and in its place was a large beat up hole where it formerly resided. It is amazing the engine ran as well as it did, but it probably would not have gone much longer before the piston self distructed inside the cylinder.

Good job flying the airplane. That always comes first.

dd
 
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Wierd guage readings

Flying back from the Redneck Riviera a while back, I noticed high readings on my Van's guages. Pulled the power back and began to divert to the nearest airport. About then my Dynon D-10A died. Looking around at various readings, I noticed on my portable GPS that the Bus voltage was just over 9 volts. Started checking circuit breakers and noticed that the alternator circuit breaker had somehow been turned off. Radio was still on so I turned the Avionics master off, switched on the alternator CB, turned the Avionics back on and everything was back to normal.

In my case the high readings were due to low voltage. Poor grounding can cause the same problems.

Can't say enough about the Oddysey 680. It had started the engine (I0-360)and run the entire system for well over an hour at this point. It's nearly 4 years old and did all my avionics testing. No idea how many times it's been recharged with a wall charger during this time.

Mannan Thomason
RV-8 N161RL
49.7 hrs and still grinnin!!!!!!!!!!
 
Frank It Doesn't Ever Get to be Fun for Me

The common opinion is the Instrument Rating is the most difficult and most important to get if you are going to travel. A chance demonstration by FAA an accident prevention specialist (me blindfolded in a spinning chair) at a McDonnell Douglas Flying Club Christmas Party prevented four people getting killed by me ala JFK JR. a couple of months later on a return trip from Tucson. With a little over 100 hours total time I flew into unseen clouds, in a left turn, over the ocean at night off the coast between Corona Del Mar and Laguna Beach. When I rolled out on the right heading for Orange County Airport I knew my attitude indicator had failed and I was rolling off into a right turn. The need to roll back left was overwhelming and I know as my airspeed would have increased and the altitude decreased I would have pulled back on the yoke ... The FAA guy and his demonstration was all that intervened. After some agonizing time we popped out in the clear on the other side. I am strictly a private pilot and my log shows 1123 instrument approaches, don't like it at all but I got the rating and maintain it because I like to travel. In my case at least it is never something I look forward to in my RV but being able to deal with it is essential to reasonably safe travel. The Tru Trac altitude hold (Altrac) course control Pictorial Pilot are WONDERFUL additions to my airplane. Some fear during the training phase is not a bad thing I think. It helps to emphasize the importance of learning your IFR skills.

Bob Axsom
 
Having problems with oil temp readings on Dynon ems as well.Even after the updates the oil temp differs up to 40 gedrees in similar flight conditions.Checked the sensor. maybe the bypass valve is sticky, I really dont know.
 
Bob Axsom said:
The Tru Trac altitude hold (Altrac) course control Pictorial Pilot are WONDERFUL additions to my airplane.



Bob Axsom
Click to expand...

Bob,
I'm close to buying a Tru Trak pictorial pilot and replacing my Sigmatek AH and DG with it. Does it supply pitch info as well as bank? If so, is it as accurate as a vacuum gyro?
Regards,
 
No Pitch Info with Pictorial Pilot

pierre smith said:
Bob,
I'm close to buying a Tru Trak pictorial pilot and replacing my Sigmatek AH and DG with it. Does it supply pitch info as well as bank? If so, is it as accurate as a vacuum gyro?
Regards,
Click to expand...

It is very acurrate (amazingly so) but if you turn the autopilot function OFF but leave it powered on just to read the course display, and bank over into even a standard rate turn it stops the display until you roll out on your new heading. It requires the serial output of a GPS as one of the inputs but I have never seen the design so I do not know how the signal processing is done or how it is used. I am reasonably sure that it contains a solid state gyro as well. I have read about Jim Younkin's partner and found that he has an extensive software background so I am sure there is a significant amount of digital processing running continuously. It takes time to process all of the serial start bits, stop bits, data bits, sync bits, error detection, and handling for input/output in addition to all of the internal data management and processing so even though display changes appear real time in near steady state flight it would not be surprising to learn that the input to display time lag during a major turn falls behind and the display is blank until the turn stops and the processing catches up and good information is verified. Pictorial Pilot is intended to replace the turn coordinator and it does this very well rate of turn display is constant and if you buy the ~3" model it includes the inclinometer (ball).

Pictorial Pilot provides no pitch information but the company developed a unit after I bought my Pictorial Pilot that is intended to replace the Attitude Indicator+ And you may want to look at that. The Pictorial Pilot and Altrak have made my RV-6A a pleasure to fly in mild IMC. The newer system sounds even better.

Bob Axsom
 
Funny you should mention that

Paul 5r4 said:
I've got a 7A coming by Friday of next week and planned to use the Dynon as my EMS system. FrankH..... I read your post with great interest. It really seems to me that with the other insturmentation quirks you noticed, you may have had a moniter problem. What's the common denominator here, I don't know. It does make me think that if you had had a basic old standby type oil temp gauge which had a normal reading on it, you'd have felt more comfortable about proceeding. Kinda making me think I might put one in now. GLAD YOU AND YOUR CFI AND THE PLANE ARE SAFE!!! What are your thoughts on haveing the basic back up instrument???

Paul Gray
RV 7A QB
Foley, Alabama
Click to expand...

Never occured to me prior to yesterdy to have backup engine instrumentation, but it sure did as I was looking at the top of the cloud layer coming up, everything at redline and we hadn't been cleared for the approach yet.

I would have paid good money yesterday to have been able to flip a switch to checked oil temp on a seperate guage and wonder if there is a simple oil temp/oil pressure guage that could be wired thru a switch to read from the same sensors.

The DYNON seems to be the only common denominator here, could be a bad ground but it was reading battery volts as normal....Unless something really bad has happened to the engine but I would have expected to find something else, like low compression due to a holed piston, half the oil blown out the sump, running bad etc.

Sure makes me nervous about strapping myself into it before I got it figured out.



Frank
 
frankh said:
I would have paid good money yesterday to have been able to flip a switch to checked oil temp on a seperate guage and wonder if there is a simple oil temp/oil pressure guage that could be wired thru a switch to read from the same sensors.
Frank
Click to expand...

Van's has a low oil pressure switch that is tapped into your engine oil pressure gallery that has a couple of wires that goes to an idiot light in your panel that will tell you if your oil pressure is getting low. I think it is set around 25-30psi setting? Another nice thing about the idiot light is that when the engine is shut down the light is ON reminding you to shut the master off and not run the battery down. I installed one on my -6 because I lost my Vision Mycrosystem panel one time and I lost everything. I know how you feel when your engine monitor goes on the blink. No oil pressure and the prop quits turning. Redline oil or CHT temps with oil pressure and the engine should run until you get on the ground safely.
Summit Racing, Jegs or Speedway motors also has oil temp sendors in various temps, 220F, 230F, 240f that will light up an idiot light if the oil temps reachs that peak. I know this is not what you were looking for to tie into your current probes but it's an idea and it's seperate than the system you have. Good luck and hope you find the problem.
 
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Call me old fashioned but I do not want to put all my trust in something electrical when it comes to oil pressure. I have a VM-1000C and a backup mechanical oil pressure gauge which is connected by 1/8" copper tube into the side port of the VA-168 transducer manifold on the firewall (the electric transducer is in the port on the front of the VA-168).
Fin
9A
Australia
 
Finley Atherton said:
Call me old fashioned but I do not want to put all my trust in something electrical when it comes to oil pressure. I have a VM-1000C and a backup mechanical oil pressure gauge which is connected by 1/8" copper tube into the side port of the VA-168 transducer manifold on the firewall (the electric transducer is in the port on the front of the VA-168).
Fin
9A
Australia
Click to expand...

Ditto on that, Fin.

I had the VM-1000 in my Cozy and its transducer failed one day - really caused some pucker time. A backup steam gage was installed after that event with its own sender. Oil pressure is one item we need to know about and a backup light or another gage is a good move.

dd
 
The Dynon has a well-known oil-temp indication issue if the ground from the instrument to the engine block isn't just perfect. The resistive OT sender is running very close to ground, so any difference in ground potential between the instrument and the engine shows up in inaccurate (and varying) OT indications. Just ask me how I know...

Now, for the EGT and CHT, that's a different deal. These probes are internally referenced, so they're not subject to the grounding errors.

If ALL temps go up wickedly, I'd suspect an internal problem with the Dynon. FYI, when I was fighting the OT indications, my EGTs and CHTs were fine.

--Marc
 
After a little checkout

This is what I found...NOTHING!

Wiggled all the ground wires and everything seems to be as it should. Mahlon suggested I borescope the motor as it may have lost its timing and caused pre-ignition. A fair idea but I reasoned if the motor had thrown a wobbly that it would 1) run like a bag of nails 2) It would stay broke...i.e would not be normal again 3) didn't account for the other spurious readings in the tach or EGT signals...Of course I didn't tell him about #3...:)

I was also slightly nervous cus this happened part way thru my second ever fill up mogas..Uh oh?

So it seemed to me the prudent thing (being as we had a rare evening of VFR weather) was to fly the thing and see what happened after a thorough run up.

Well guess what, it ran beautifully...No problems at all. Flew the same flight profile...high power climb, pull back to LOP...Flew for 40 minutes or so...No problem.

I think we can safely discount the engine unless somehow the Emag/Pmag went nuts with the timing....But then it ran smooth the whole time.

So now what?...Thinking I might remake all the ground lead from the EMS direct to the battery and engine block...i.e a 14Ga dedicated ground.

Other than that I don't know what to do except if it does it again to send the unit back to Dynon for testing.

Weired and I don't like it.

Frank
 
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