forced landing-smoke in the cockpit

[Jerrytex]

I had a forced landing today due to smoke in the cockpit. Fortuanetly I was nearby the airport and landed safely after shutting down all the electrical. After removing the foam donuts that my butt cut out of the seat pads, I started troubleshooting. I found that one of the wires from the coils/alternator where it goes into the regulator was fried. Is there a way to test the Ducati regulator? Any ideas on what is going on? I heard a loud squealing in my headset when the smoke got real thick so I wonder if the problem is in the alternator part or in the regulator. Any help is appreciated. Now I am going to have a stiff drink.

Jerry

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[Dorsal]

Glad you made it down safely, looks like possibly a problem with the crimp? Do you have signs of extreme heat anywhere else?

[Jerrytex]

That's the weird part, it is only burnt on the end where it plugs in. I know that loose connections will do strange things, but this connection seems tight and clean. It would seem that if the Regulator all of a sudden switched to ground, it would have burned the entire wire not just an inch. After I landed, I turned everything on and it worked. Even ran the engine at idle and the wire didn't burn further. I am tempted to cut off the damaged part, solder a new end on and try again but it took 10 hours in phase one for this problem to surface. I don't want make it a habit of emergency landings!

[kmach]

Hi,
my experience with regulators is , if they burn out it is real noticeable. the back of them melt.

They don't do anything once burnt and you will not have any charging , but this is just my experience on one regulator.

From your pictures it looks like a loose connection, though, as you said it seemed tight. I think the same as you, repair the wire, ensure it is connected good , and retry.

[cap01]

jerry , do you have a crowbar installed in the system ?

[Jerrytex]

Not sure what a crow bar is? I am thinking about putting a switch between the "alternator" outputs and the regulator. That way I can turn off the output before the regulator in case I run into this again. I have a Hot box but it hooks in after the regulator. It's strange that there is no fuse or safeguard before the regulator. Maybe that's what the crow bar is? I am a pretty mechanical person and experience is pointing towards a bad connection but...damn, all that smoke was a little spooky especially for a new pilot like me. I would like to do everything possible to make sure I have whatever is wrong fixed before I continue on.

[Monocock]

Glad it ended safely.

[Jerrytex]

Thanks everyone for the input. When this happened, all that was on was the radio and intercom so no big load. However, up until this day, I have done mostly touch and goes, stalls, etc. so the engine never ran for more than 10-15 minutes or so a full throttle. This day I was out messing around a river so I was at 5500 rpm for over 20-30 minutes so the alternator was putting out full power longer than any other time. I am kind of wondering if this gave the bad connection enough time to to get enough resistance to melt the insulation?

I think my game plan now is to re-do the connector. I think I am going to solder them to make sure the connection is good. This part of the electrical was done by another builder so I didn't have any input other than checking it to make sure it was right according to the manual.

The one thing I noticed now is it seems there should be a switch to turn the output from the alternator off. Kind of like a "crow bar" but something I could turn off in case this happens. I always thought that when the master is turned off, it shut all the electrical off but now I realize this is not the case since the alternator is still powering the regulator. After I saw the smoke, I shut the master off and reduced my rpm. The smoke subsided and most blew out during my 2000 fpm slip to the runway. The crazy thing is, in theory, turning the master off did not stop the alternator output so the wire should have continued to burn. I am wondering if reducing the throttle thus reducing the alternator output is what stopped the smoke? Has anyone put a switch in? If that is not a option, is the crow bar just a circuit breaker that I could buy at an auto parts store? I guess a panel mounted C/B would essentially be a switch. If this ever happened again, I could kill the master and pull the breaker. This might be a better option?

[Dorsal]

Shutting the master off should remove the load from the Alt, the load at the time of your event may have been charging the Batt. The only place I have seen a switch recommended is after the regulator to disconnect it from the system if it looses it's cookies (also what a crowbar can do). The Alt will not put out much current if there is no load on the Regulator.

[Jerrytex]

Interesting. That makes sense. I guess with the load turned off there really would be no need to put switches in.