Nearly had one.....see attached pictures.
The aircraft is a Piper PA46-Jetprop. For those who aren't familiar this is a stock piston PA46 that is STC'd by Rocket Engineering in Spokane, Washington State. The piston engine is removed and replaced with a PT6 - in our case a PT6A-35. The best aircraft I have ever owned - built for 310HP and now had just shy of 570 SHP. Just crazy performance....
For those who maybe haven't flown a PA46 the CB panels are on the L hand sidewall by the P1 position. There are two banks of CB's - an upper half and a lower half.
Well - flying along one day we started to get this kind of gentle 'fried insulation' smell. No smoke, no fire - just a smell. And not that much of it either - and it went away. Then it came back on another flight and I just started to get a bit concerned. So when we got home we unscrewed the top CB panel and took a look behind. Yikes....
The large cables you see are the main power supply cables from the battery master solenoid all the aircraft systems. They are held on to the bus bar by one screw - the crosshead screw you can see. This had come loose over time and had created a high resistance environment.
The bus bar handles all electrical systems (bar the starter generator) and there are a lot of electrical systems on a PA46 - including the windshield heating (20 amps) the prop and inlet lip heating, etc, etc. The starter-generator can push out 200 amps and with everything turned on then one can see 80 amps plus on the displays.
Not good.
This had to be totally rebuilt and needed quite a few new CB's that had cooked themselves.
Paul
View attachment 31965