Hi. Do you have a date field in one of your sheets? You'll need to convert this to a SUMIFS, and include the date field as part of your calculation.

Let's say your Flight Activity Report looks like this:

On your summary sheet, where you are calculating flight time in last 30 days, you can use this formula:

=SUMIFS({Flight Activity Report Flight Minutes}, {Flight Activity Report Pilot}, Pilot@row, {Flight Activity Report Flight Date}, >=TODAY(-30))

Placing this formula in the "Minutes Flown in Last 30 Days" column will calculate the total flight time for each pilot in the Pilot column for the past 30 days.

You can alter this to suit whatever columns you're working, but I encourage your to name your cross-reference ranges instead of using Smartsheet's default values of "Range 1", "Range 2", etc. That way, you can more easily find errors in your formulas and you can visually track the logic of them later.