Angels good and bad; some lost their positions of authority, some did not

Jude 1:6 And the angels who did not keep their positions of authority but abandoned their proper dwelling - these he has kept in darkness, bound with everlasting chains for judgment on the great Day.

2 Peter 2:4 For if God did not spare angels when they sinned, but sent them to hell, putting them in chains of darkness to be held for judgment; 

Some angels are good and some are bad, the demons or devils. They are described here as those who sinned and so did not keep their positions of authority but abandoned their proper dwelling (heaven?) and were sent to hell. God has kept them in darkness, bound with everlasting chains for judgment on the great Day. They may seem unchained but they are not really. When were they actually hurled down to hell? Probably when Christ died on the cross.