Examples of closed loop control system?

A SYSTEM is any active device if left as open loop it will saturate one way or the other if the gain is ample. To control a system it must have some feedback to determine ts linear operating capabilities. As an example an airplane taking off at Las Vegas the cabin will be pressurised to -1000 feet from the ground and maintain a rate of climb to even 50.000 feet with a delta of 17 PSI The cabin pressure as a system will maintain this delta by close loop control otherwise we will need oxygen if flying. INTERESTING?