my sk450 through a wobbler today and crashed HELP

[stevestoys]

Took my quad out today and fine tuned my kk2 board a bit. About 4 mins into the fpv flight I was impressed how I had kept it low and was not struggling to control it then it just flipped and came down. I use an frsky system and had no bleeps so not range or interference. Was only about 50 yards away but I heard the motor speed up and it flipped over. Any ideas. No damage only 4 props. The video didn't come out for some reason. Could have been the upside down landing that did it. Shane as it was going so well. Was on my second battery and have a lipo alarm which didn't bleep either. Strange HELP

[tdmodels]

Were any of the prop nuts loose afterwards?  Or perhaps could one of the props disintegrated on flight?

[stevestoys]

Just checked and one was very loose. How good are you lol. Cheers bud I'm happy now

[Hubsanman]

I'm always checking all bolts and prop nuts on my quad, the vibration gets to em.