according to ICAO, a landing aircraft cann't be directed to cross the threshold of the runway until the preceding departure one has crossed the end of runway. How to apply this rule?
The version of doc. 4444 that was available last year,when I prepared something
,
had such possibilities.
I can't now give you more precise answer but glimpse at new version of document and you will see it. also it is clear stated that such procedures(reduced separation between dep/arr and other combinations) must be approved by appropriate ATS authority .
Practically it means there is no reduction in separation in many countries around the world. As you may know DCAs and similar institutions aren't usually informed about problems and possibly solutions
Also I believe that set of technical devices should be employed for such procedures and that means:new procedures,tenders,corruptions, approvals....
It wouldn't work....