A few weeks back I lost my electrified Great Planes Giant Scale Reactor airplane... went in hard with no control what so ever. Some at the field said they never saw balsa bounce that high ever!
So what happened you asked?... Simply, a Deans connector failed due to excessive current and carbon build-up from sparks/arcing. What appeared to have happen was during its last flight, I pulled over 100 amps of current through a measly Deans connector a few times during one flight, so much current that the Deans connector heated up, the internal spring pressing the connections together got weak and the contacts began separating, causing arcing and carbon buildup... enough build up that the contacts eventually opened up (no power, no control of plane).
The attached picture indicates this arcing that occurred... luckily I salvaged all electronics including the brushless system and was able to pull the data off my Castle Creations ESC logger, allowing me to view V & I data postmortem...
Ths plane only had 9-10 flights on it and I never downloaded the data to view performance... else had I done so, I would had noticed the excessive current it was all pulling, prompting me to change over to better connectors (like the large Anderson Power Poles I use on my large electrics).
So... lesson learned...
Always take measurements and check your performance parameters before pushing the airplane.