Originally Posted by Lon More
Waiting until they were only 15 miles apart was leaving it much too late. If another a/c had made acall he'd have lost separation anyway.
The cause of the separation loss had nothing to do with waiting too long. It had to do with call sign confusion and subsequently instructing one aircraft to climb into the other's path.
This is a nasty combination of callsign confusion and expectation bias.
If he wouldn't have asked CLX749 to climb just a minute ago, his mind would not have been preoccupied and he'd probably would not have confused the two or at least verified the call sign.
In my opinion this could happen again to any other controller. Firing the guy does not help safety at all.
Instead they should showcase this incident to airlines to stress the importance of avoiding call sign similarities.
If anyone from an airline's flight planning office reads this, you might want to read
this link.