Delta plane's emergency slide falls off during flight

[SoCal Mac]

https://news.yahoo.com/delta-planes-emergency-slide-falls-193700396.html

More bad news for Boeing.

Makes me wonder if the flight crew even bothered to do a walk around before take-off.

[DaveReid]

Needless to say, it was one of the overwing slides (there is no way a door slide could depart the aircraft without the door first opening).

I very much doubt there would have been any signs of the incipient failure visible on the walkround.  Pilots aren't normally expected to climb up on the wing.