Vertical Separation.
 

Can anyone help, please? I'm not in the "Biz", just a dedicated enthusiast.
This afternoon, I was watching two airliners, in a beautiful clear blue sky, flying over me, and directly away from me.
At first, it seamt that they were flying parallel to each other, and they were abreast of each other.
In fact, their paths converged, until one passed directly over the other one. I know that they were not really close to each other, and the angle I was then viewing them at exaggerated the fact.
What I would like to know is, what would their vertical separation have been? (Quadrantal rule?)
Thanks. N.Z.

2000' minimum going the same way.

Thanks for that, Notso.
Regs. N.Z.

Noah,

Here in Dunnunda minumum separation would be

• 1000' if below Flight Level 290 (FL290),
• 1000' if above FL290 and both aircraft were RVSM approved (Reduced Vertical Separation Minimum)
• 2000' if above FL290 and either one or both aircraft were not RVSM approved.

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2000' minimum going the same way.

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Not necessarily. They could have been 1000ft apart waiting for the cross to continue further climb.