Notifying players when events are coming?

I'm having a hard time finding a plugin that tells the next time events occur. I've seen it on many servers, commands like /cargo, /heli, /chinook that give an exact until they arrive. i.e.

Input: /heli

Output: Heli arrives in 0:32.

I'm just looking for a link or name of the mod, thanks!

I'm looking for something that tells players the time when it comes out beforehand, not just at the time of event. Thanks tho!
You could easily call the events yourself and send notifications beforehand using plugins such as Timed Execute or Timed Events.