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Didn't fly, airplane problem


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Was going to take a short trip at lunchtime today, start was normal as warmup, taxi, going thru the checklist.  Runup was routine, mag drop was about 75 each, as was carb heat, prop cycle, etc.  Tower clearance, turning onto the runway, it felt like a flat tire, or rumble strips on the highway.  I let it roll on the runway a little, fed a little power, the engine shook, ran rough, backfired a couple times.  Pulled power, told tower there was a problem and was going back to parking.  Stopped along the way, ran it up a little, yes it was plenty rough.  right mag was smooth, left mag wouldn't run.  It would cause a backfire about once a second or so, but otherwise the left mag wasn't going to run the engine.  It was working great until it wasn't.  I'm expecting to find some nylon gear teeth sheared inside the mag.

I was planning an annual at AGL end of the month, was going to ask Lynn a few questions about the SureFly SIM.  I guess this hastens that conversation.  In the meanwhile, I need to get the plane up there.  Anyone have a spare, useable, shower of sparks Bendix mag they could loan/rent me for 6 weeks?

Over the years I can only think of a few aborted trips due to problems found on the ground.  Two vacuum pumps dead on startup.  One, maybe two alternator/regulator/wiring not supplying power on startup.  A flat main strut on the Bonanza. After having a SB done on the Bonanza interior door handle, I found myself locked in the airplane after taxi to the fuel pump (mechanic got a 5 AM wakeup call).  That's it, all remembered.  Not bad for 43 years flying nearly every week. A whole bunch of stuff broke while flying, a few more things were found after a trip like a big puddle of oil in front of the hangar, coming out of my engine right then.  What mechanical surprise has stopped your trip before getting started? 

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I had a very similar event a couple months or less ago, wouldn’t fly it to the MSC had a mechanic fly in, had lead in one bottom plug. Cleaned all plugs checked gaps now runs like a champ where I expected to spend a few grand it was a couple hundred but if I cleaned them myself it’d only be time. At least I got to use my plug blaster again.

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See if Lyn has one on the shelf...

It sure would make the return of the hardware easy... :)

 

My prior to take off failure was a prop gov not working correctly...

The crankshaft seal allowed the oil pressure to leak back into the case... and not operate the prop...

The gov was fine, prop was on the fine limits...

So the gov check failed...

Best regards,

-a-

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I had a very similar event a couple months or less ago, wouldn’t fly it to the MSC had a mechanic fly in, had lead in one bottom plug. Cleaned all plugs checked gaps now runs like a champ where I expected to spend a few grand it was a couple hundred but if I cleaned them myself it’d only be time. At least I got to use my plug blaster again.

Standard operating procedure when engine run up is not quite perfect, run up engine to 1500 RPMs or so and lean it until it drops to 1100 or less. It sounds awful but 30-60 seconds will clear any lead build up.
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46 minutes ago, David Lloyd said:

What mechanical surprise has stopped your trip before getting started? 

Doing the "controls free and clear" check found an errant wire bundle caught in the controls under the panel.   Only took a few minutes back at the hangar to zip-tie it back out of the way.   I've no idea what changed under there that it had never been a problem and suddenly was.

Luggage hatch popped open on take-off roll once after I got distracted getting in the airplane and didn't latch it.   I aborted the take-off in time and there was no damage, but it was one of those things that'll get your attention in a hurry.   I've since sorted out that my minor mod to add an interior release also provides a means for me to see whether it's fully latched or not by looking from the pilot's seat during pre-start checklist.

I caught my prop governor failure during runup over two flights.  On one flight it seemed like was a bit lazier than usual, and on the next it took way longer to cycle than usual, enough that it was obvious something wasn't normal I wasn't comfortable flying it.  So far that's been the only one where it couldn't be fixed in a few minutes and actually cancelled the flight.

 

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Many years ago I had sold my 20-F and bought a 1954 Bonanza V-tail with an old style electric variable pitch prop.  My wife and I had it all tested, fueled, loaded up and ready to fly from central Florida to Vermont.  I had filed a flight plan for a 3.5 hour leg, opened my flight plan, taxied to the the of the runway, and did my final run up before calling the tower.  Uh oh.  The pitch on the prop was badly out of adjustment, for some strange reason, and we had to call the flight off.  Would not build RPM.

We had already taken the time off at work and had paid for a cabin in Vermont, so we ended up driving.  And driving.  Oh, and driving home.  No fun.  

When we got back home 8 days and MANY miles later, I put the V-tail in the shop. They had a mechanic that had worked on an electric Bonanza prop several years earlier, and ours needed a moderate adjustment.  That’s when I realized I wasn’t going to be able to depend on that airplane.  It’s one of the reasons I sold that old hunk of junk and bought a Mooney 20J eighteen months later- which we flew to Vermont a few years ago.  

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1 hour ago, ArtVandelay said:


Standard operating procedure when engine run up is not quite perfect, run up engine to 1500 RPMs or so and lean it until it drops to 1100 or less. It sounds awful but 30-60 seconds will clear any lead build up.

Or sometimes you have to get more aggressive with it. Although at that point I’d probably just take the plugs home and run them through a sand blaster. 

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1 hour ago, RobertGary1 said:

Or sometimes you have to get more aggressive with it. Although at that point I’d probably just take the plugs home and run them through a sand blaster. 

Can't do that with the fine wires, which do get lead fouled occasionally.   They seem to respond well to getting them hot during a runup, though.

 

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My issue 3 months ago.......left mag failure in flight.  

Engine suddenly ran rough.  Switched from “both” through R and L positions..... wowie! L mag would not operate engine.  Backfires, spitting and coughing.  

Ok, got it, yikes, don’t even think about returning to left mag or both.

Switched to right mag and headed back to airport.

Per Aero Accessories (Van Nuys, CA), capacitor failure.  No charge to diagnose and replace.

All is well once more.  :)

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Left word for Lynn just after getting home.  I plan to ask if he has a spare to use to get the plane to MRN.  Swapping out a mag isn't a big deal, just frustrating with a several busy months just begining.

 

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20 minutes ago, David Lloyd said:

Left word for Lynn just after getting home.  I plan to ask if he has a spare to use to get the plane to MRN.  Swapping out a mag isn't a big deal, just frustrating with a several busy months just begining.

 

Hi David,

You might message Hammdo as I put a SureFly on the left mag position before delivering the airplane to him. He has a left shower of sparks mag on the shelf. 
It’s worth asking.

Thanks,

David

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Yep I have a left one. If you need it, I’ll be happy to send it to you so you can get to where you need to. Call if you like 214.675.5092...

 

-Don

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3 hours ago, MooneyMitch said:

My issue 3 months ago.......left mag failure in flight.  

Engine suddenly ran rough.  Switched from “both” through R and L positions..... wowie! L mag would not operate engine.  Backfires, spitting and coughing.  

Ok, got it, yikes, don’t even think about returning to left mag or both.

Switched to right mag and headed back to airport.

Per Aero Accessories (Van Nuys, CA), capacitor failure.  No charge to diagnose and replace.

All is well once more.  :)

When my left mag died in flight, the EGT was wonky. It kept rising and I kept richening--until I looked diwn and it was above redline. Then I thought, Huh. I should test the mags. Moved the switch from Both to Left, the engine noises stopped and the nose pitched down to maintain 145 mphi at 9500 msl. Got my wife's full and complete attention, too, but I was concentrating on troubleshooting and can't say I really noticed it in any detail. When the key hit Right, it got noisy again and leveled off, so I left the key alone, releaned, climbed slowly back to 9500 then started paying attention to the other non-engine sounds in my headset.

I did learn, though, to discuss strange happenings in the cockpit before fiddling with controls that may kill the engine. Obviously the flight ended successfully, except for the pain of an out-of-town magneto repair. I still don't understand why repairs cost so much more when you're away from home. But my hearing may have been damaged that night, so please repeat the explanation . . . .

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My AOG before I left the G was a few months ago. Details in a different post. But 0 EGT indicated on #1. Thought it was a sensor issue but then it was rough running on power settings above 1000 rpm. Turned out to be a loose intake valve seat that had the intake stuck open. Glad it happened on the ground!

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Even at idle speeds, the EGT was higher than normal, and doing a dance when on both mags.  Dropped like a rock any time the left mag only was selected. Always lean on the ground and do not have a problem with fouled plugs.  Will phone Hammdo Monday, swap mags and send mine for evaluation. Thanks all.

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Ran up the airplane, everything seemed fine, cleared for takeoff and the engine stumbled as I advanced the throttle.  I aborted the takeoff and exited the runway, the engine didn't want to idle. I managed to taxi back to the hangar.  After some troubleshooting, I found that fuel was dripping out of the airbox when I ran the fuel pump.  The failure to idle and the stumbling was caused by an excessively rich mixture from the extra fuel being introduced into system. 

I drained the carb and found a bit of fine debris in it.  I filled and drained the bowl a few times until clear, checked the fuel screens finding nothing.  This solved the issue and the engine ran fine, but this took a few hours figure out and I ended up having to take my trip the next day instead.

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Why not go straight to the SureFly now? Save yourself a couple of hundred dollars labor and postage on the loaner mag. SureFly will overnight it to you if you want.

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14 hours ago, EricJ said:

Can't do that with the fine wires, which do get lead fouled occasionally.   They seem to respond well to getting them hot during a runup, though.

 

Tempest suggest using crushed walnuts blast at low pressure at very short intervals, glass beads have a good chance of lodging in the plugs and melting at temp leaving a film which impairs the spark. 

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1 hour ago, kmyfm20s said:

Why not go straight to the SureFly now? Save yourself a couple of hundred dollars labor and postage on the loaner mag. SureFly will overnight it to you if you want.

Changed to another airport last year.  Even though I have dealt the shop owner at this airport in the past, the relationship is not good.  Last year a $350 oil change, and an upgrade that was scheduled months in advance.  An email Thanksgiving Day saying they would not be able to do my upgrade.  Not even a phone call.

Yes, if installing the SureFly now can be done, it will be.  Matter of logistics arranging for someone to do the work here.

 

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2 minutes ago, Browncbr1 said:

If you have 25 degree timing, make sure you have the correct mag drive gear if you order the surefly.  

I knew some people had difficulty with the drive gear from the original mag and not able to set the timing properly.  Is that the problem, 20 versus 25 degree timing?

But yes, mine is 25 degree.

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