Originally Posted by HSaxa
Of course, I am no expert on this, but maybe someone can tell me ways of knowing when close is too close? Meaning, I know the requirement is 1000ft or something like that, but what does that look like when you're staring out the window?
Too close is when you hear it.
If you got to less than 5 miles separation or 1000 feet, you would likely feel some effort (climb, turn, descent) to get separation. But yes, 1000 feet looks close. Head on the closure rate is 16 miles a minute or a mile every 3 seconds. By the time you process it, the other plane's about two miles away.