Is the attached what you are looking for (sheet4) ?
Simply calculate the In Air with the SUM of
when 'D' then 1
when 'A' then -1
and create a filter
[DATETIME] <= [FIXDATE] and keep the true values
Plain Test ed mc.twbx 22.3 KB
Thank you Michel!
Indeed sheet 4 calculates what I wanted in a very elegant way. It was very helpful.