When testing my Ultimate 40S just before I was about to tear it apart again, it appears that everything still works fine. Although I am a bit puzzled about what happened during the test flight, I now feel that it must be some shutdown function of the Phoenix HV ESC. The pilot (Devin McGrath) properly tried to re-arm the ESC in flight and we also did it again on the ground without success. This was after a complete re-power up sequence as well.

My BalancePro HD DPM wasn't sounding the audible alarm after the crash but I will still disable it for the next flight test. I will also remeasure the current to see if perhaps the ESC hit an overcurrent shutdown. According to the Phoenix HV 45 instructions, either an overcurrent or undervoltage condition will cause a "soft" motor shutdown. I didn't see any mention of a re-arming procedure.