ORIGINAL: Flypaper 2
Did you have the throttle failsafe set to shut off?
Having the BEC of the ESC go out would cause exactly the given problem. I have burned out the BEC on Speed controls by exceeding the recommended 2-3 microservos specified. I had a plane - Paramount Sport conversion - and maidened it in February last year. I flew it for about 2 months, then retired it to fly another plane. I resurected it in July and using everything the same, it was kind of slugginsh, and erratic. The batteries were coming down hotter than usual, but not real bad. In Late July on a particullarly hot day, it suddenly locked up and crashed. The Speed control was fried. I suspect that the hotter day, caused the speed control to overheat and burn out.
The only other explanation would be a complete flooding of the entire Spread Spectrum band with an extremely strong signal. I understand this can happen if you fly withn 2-5 miles of an airport using a certain type of radar package. That's only something I heard in passing, and not sure of.